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Plant & Insect Clinic Advise

The Master Gardener Plant & Insect Clinic diagnosis team publishes short columns in the Master Gardener’s internal publication Sage Advice.  Some of their articles are general interest, some are nitty gritty science, and some address specific plant care.

The Diagnosis team shares this information with inquiring gardeners.
Contact the Plant & Insect Clinic for information on these or other topics.

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Bugs, Insects and Spiders

Good Bugs – 6/1/2016

Gardeners who bring bug problems to the clinic usually have only one question: How do I get rid of this pest? For many, all bugs are “bad”. While most are aware that ladybugs are good to have around, they don’t know of the many other beneficial insects that visit their gardens nor that 90% of insects are benign. Last month we reviewed six bugs that create problems for gardeners. This month we’ll look at how to encourage six species that are beneficial for our plants: damsel bug, ground beetle, lacewing, ladybug, praying mantis, and tachinid fly.

The damsel bugs are natural enemies of aphids and small caterpillars such as cutworms and tobacco budworms. They are light brown or tan, narrow-bodied insects with long legs and bulging eyes. They use their long snout to kill and eat their prey. They overwinter in leaf litter and grasses. To encourage their presence in your garden, plant low growing perennials and ground covers.

Beetles are some of my favorite insects. Ground beetles will devour, among other things, caterpillars, Colorado potato beetles, corn ear worms, cutworms, and slugs. They have a hard dark-colored shell and can grow up to 1 ½” long. They use their large mandibles to capture their prey. This mandible often worries gardeners who fear being pinched by them, but don’t let it stop you from encouraging their presence in your garden. Ground beetles feed at night, living under rocks, logs, and leaf litter during the day.

Lacewings are many peoples’ favorite insect for their delicate beauty: light green colored body, transparent wings, and golden eyes. Though only a ½ inch long, the larvae can eat up to 100 aphids per day! They also consume mealy bugs, spider mites, scale, and whiteflies, among other pests. The adults don’t feed on insects, but rather are pollen and nectar feeders. So to attract lacewings, grow plants such as coreopsis, cosmos, goldenrod, Queen Anne’s lace, and yarrow.

Most children can identify ladybugs, also known as ladybirds or lady beetles. They are amazing insects. Over 450 species are found in North America. Like lacewings, their larvae are voracious feeders, with the ability to consume 40 aphids per hour! Ladybugs at all stages of its life cycle can be seen on the same plant harvesting aphids. Adult ladybugs are pollen and nectar feeders as well as insectivores, so grow plants such as cilantro, coreopsis, dandelion, dill, fennel, and yarrow to attract them to your garden.

I remember being fascinated by praying mantids when I was a child. What I didn’t know then is that they can turn their heads 180 degrees, using their large eyes to find their prey. Sneaky insects, they lay in wait for their meals of aphids, caterpillars, Colorado potato beetles, squash bugs and others to come to them. One disadvantage is they eat other beneficial insects in addition to the pests you want gone. They lay their eggs on plants stems and branches, so grow sturdy-stemmed plants in your garden.

Although most of us find flies to be pests, the tachinid fly is our garden’s friend. They can be confused with small houseflies, but rather than hanging about on your screen and in your kitchen, you will find them pollinating flowers and settled on leaves. As parasitic insects, adults lay their eggs or live larvae on other insect hosts such as Colorado potato beetles, cutworms, earwigs, and squash bugs. The larvae feed on the host insects. Tachinid flies particularly like herbs, adding to the value of your culinary herb garden!

For more detailed information on these and other beneficials, Good Bug, Bad Bug: Who’s Who, What They Do, and How to Manage Them Organically by Jessica Walliser is a good resource and the one I used to write this article.
By Casey Leigh.

Hobo or House Spider? -10/1/2017

Of all the “bugs” brought into clinic, the ones that cause the most consternation are spiders. Although most of the insects we see can be hazardous to plants, they rarely bite humans or even work their way inside houses. Spiders’ reputations for causing painful bites, however, precede them. In reality, spiders as a whole are so beneficial that WSU extension does not recommend using pesticides on them.

One of the spiders found in our region that has been known to bite humans is the hobo spider, Tegenaria agrestis. Although studies have not demonstrated that hobo venom causes necrotic skin lesions, hobo spiders still create fear in peoples’ minds. Because hobo spiders look similar to harmless house spiders, they are often confused with the house spider. Although you can’t positively identify a hobo spider without a microscope, with practice you can learn to identify house spiders that are NOT hobos.

First, hobo spiders are outdoor spiders and are unable to live inside permanently. So the odds are slim that the “look alike” house spider is a hobo. The time you are most likely to encounter a hobo spider in the home is in August and September when the males are wandering in search of females. Hobo spiders make funnel webs, but that is not diagnostic as many other species also make funnel webs. Both house and hobo spiders are brown, so color alone also won’t help. While most hobo spiders have a chevron pattern on the abdomen, it is the most common markings on non-hobo spiders.

Now, disable that spider you are concerned about and get out your hand lens. Look at the sternum, the area sur-rounded by the legs on the spider’s underside. If you see 3 or 4 pairs of light spots on the sides of the sternum, your spider is not a hobo. Remember the saying: “If you see spots, then a hobo it’s not.” Next, look whether your spider has two dark longitudinal stripes on the main part of its body, the cephalothorax. If it does, you don’t have a hobo. Now look at the legs. Are there dark rings around them? Are they shiny, without fine hairs? If so, it’s not a hobo as they have fine-haired, uniformly colored, non-shiny legs. On to the reproductive organs. The male’s reproductive structure is called a palp, which is a swelled area on the end of the front feelers. If the palp is long and pointy, it is not a hobo.

To delve more into reproductive differences that will allow you to positively identify a hobo, you need a micro-scope and more detailed knowledge of arachnid anatomy. But for most of the spiders you will find in your house, the above techniques should eliminate the hobo from contention. If you are in doubt and your spider is still alive, capture it and move it outside. No more problem!

*Information for this article came from “Myths about “Dangerous” Spiders, www.; “How to Identify (and misidentify) the hobo spider”, PLS 116,; and “Hobo Spider”, Pest Note Publication 7488, University of California Agriculture and Natural Resources (May 2006, rev.),
By Casey Leigh.


Fruits and Vegetables

Clamping: Storing Veggies Underground – 11/1/2016

I grew up in a home that had a root cellar carved into a hillside. It smelled of earth and potatoes and carrots and cabbage and onions and was chilly year around. It was close enough to the house to walk through the snow to open the heavy wooden door and select the vegetables for dinner. Very few of us have root cellars anymore—and there is very little need to set aside food for the winter since grocery stores are numerous and close-by. But for a gardener wishing to prolong the pleasure of eating garden produce, storing vegetables during the winter is a joy—albeit, a bit of work.

So what would you want to store for winter treats- Potatoes, carrots, beets, onions, cabbage, turnips, parsnips? Select veggies that are not broken or cut or diseased. Do not wash them. Of course many gardeners also store their summer blooming bulbs and tubers in the same places they store the vegetables. Apples cannot be stored in the same place as the vegetables since the ethylene gas exuded by the fruit eventually will cause the vegetables to either sprout or rot.

The most important features of storage are temperature and humidity. That chilliness I recall from the root cellar was 40 degrees- pretty much the soil temperature below the frost line during the winter. This is the temperature that is ideal for vegetable storage. Some people have a basement that they can partition off to keep the storage area at a steady temperature – not more than 40 degrees and not less than 32 degrees. An outside wall on the north side of an unheated garage is also a possible site to store veggies and summer flowering bulbs. Most veggies need a bit of humidity. Onions and garlics need a dry environment.

For the last 20 years, I have stored potatoes, carrots, beets, parsnips and turnips in the garden during the winter. I read a book, A Very Small Garden. William Paul Winchester introduced me to the concept of clamping. Clamping is the process of digging a deep hole and storing vegetables in the bottom of the hole.
– Dig a wide three foot deep hole in your garden site where the soil is soft and readily dug.
– Place the veggies in net onion sacks or gunny sacks so that the tops of the sacks are covered with about 5 inches of soil.
– After you have placed the veggies in the hole, place a long pole or stake to mark where the hole is. Believe me, when the entire garden is covered with snow, it is really difficult to find the exact spot where the veggies are tucked away.
– Then on top of the soil over the hole, place 8-10 inches of chopped grass and leaf clippings. This mulch will prevent the surface of the ground from freezing.

On a frosty January night, I love to go out into the garden, push aside the snow, paw down through the mulch and reach into the soft, fragrant garden soil. The aroma is a reaffirmation that spring will come again. I take out the veggies I want to cook for dinner that night and maybe for one more day, and then seal up the hole with the soil and mulch and snow.

Clamping works until early March when the soil temperature starts to rise. At that point, the veggies will either start to grow or will rot. Ok. So this sounds like work. There is an easier way to store carrots, beets, turnips and parsnips. The easy way does not preserve the potatoes.
• Make sure the veggies are not poking out of the soil—if so, add soil around the tops of the veggies.
• Grind up leaves, mix them with straw and snuggle the mulch around the rows of veggies.
• Cover the veggies completely with the mulch. You need enough mulch so the surface of the soil does not freeze.
• Put a stake at the beginning and end of each row so you can find the row sleeping under the snow and mulch cover.
• The carrots, beets, turnips and parsnips are sweeter than in the summer, crisp and delicious.
Enjoy your garden all year around.
By Bonnie Orr.

Garden Soil Testing: An Important First Step – 4/1/2015

Soil tests offer up some valuable information that often explains patterns you may already be seeing within your garden. Have you ever planted beets in one location and watched them flourish and then planted them in a new location where they languish and refuse to size up? Beets are very sensitive to soil chemistry. Often a small Boron deficiency can be the difference between a successful crop and a near failure. Although through observation you can pose plausible guesses as to the problem (after reading a myriad of articles on the subject,) it is much wiser to throw down a little bit of money and have a professional soil analysis done. This is especially true if you intend to garden in the same place for an extended period of time.

Several forms of soil tests are available. Some are more intensive and offer up a broader zone of information on trace mineral content including Boron, Zinc and Arsenic. Some are more specific to the most common deficiencies such as Nitrogen, Phosphorus, Potassium, Percentage Organic Matter and Soluble Salt content. The soil test will tell you the amounts (often in parts per million) present in your garden soil. It will also clearly lay out if more of a specific nutrient should be added for optimal plant growth and will give a recommendation on how much remediation is needed to reach optimization. The broader of the tests is more expensive, but should be done at least once to understand the basic soil chemistry of your gardening soil.

Contact the WSU Chelan/Douglas Master Gardener Diagnosis Clinic for recommendations on where to have your soil test performed. There are several options. By Eron Drew.

How to Grow Strawberries – 5/1/2014

Strawberries bear best on 2 year old plants. With yearly division and replanting, your strawberry beds will remain highly productive. This type of planting requires some forethought and planning. Ideally, you have made space for one mature bed of strawberry plants (2 year old bed) and a second bed prepped out for spring transplanting of last year’s runners from the strawberries in your mature bed. The runners from last year can be clipped and separated from their parents and planted into this empty, spring bed. When creating a new strawberry bed, several factors are necessary for the success of the planting. The most important prep work is the thorough weeding and de-grassing of any new area that is being planted to berries. Strawberries are relatively resilient plants and can handle a minor amount of abuse and neglect but the one thing they cannot tolerate is competition with grass. Please take the time to remove all grass roots before planting your bed; you will be thankful for your attention to detail later on. If you are starting new beds and are removing sections of lawn to do so, the best approach is to dig out the section of lawn for planting a year in advance. The optimal time of year for killing grass is mid-summer. Step one is shutting off any irrigation to the site to be de-grassed. Once the irrigation has been turned off, the grass can be cut into strips and flipped over to bake in the sun using a flat bladed shovel. After several weeks, the grass should be brown and dry and the soil can be shook loose. The grass clods can then be moved to your yard waste bin. Weeding of this new bed should be done again in the spring before planting to remove any grass roots you may have missed the previous summer.

Since strawberries are heavy feeders, your bed should be properly fertilized before planting. In addition, fruit set cannot occur without regular and consistent irrigation. Simple irrigation can be created using ½ inch or 34 inch poly tubing with a dripper placed at each strawberry crown. Make it easy on yourself and hook the irrigation system up to a timer so that watering is predictable and regular. Happy Gardening!
By Eron Drew.

How to Mulch Your Garden – 12/1/2014

– Mulching is a year around project. Traditionally, we apply mulch in the fall to protect roots from frost heaving. Now it is done to protect plants from drying out. Our weather has changed in the last 25 years; we receive less precipitation in the winter. Until recently, NCW received the majority of its precipitation as snow. As you will recall, the last few winters have had relatively little snow and not very much rain. Most people who rely on irrigation water for their gardens do not apply water during the five months from October to April. That is a long time for no or very little moisture to be given to plants. Last year, we had only 2 inches of precipitation during the winter.

The soil dries out because conifers and other evergreen plants such as rhododendrons and laurels pull water from the soil for the needles and leaves. When the ground is not frozen, water evaporates from the soil on sunny days. As well, the surface of the soil is dried by the winds

Mulch applied about five inches thick will prevent the soil surface from drying out. It will also provide a bulky mass to absorb the available precipitation and release it slowly into the soil. Water generally runs off bare soil rather than soaking in. Mulch keeps the soil cool. It prevents the soil from warming prematurely. Warming might encourage the roots to think that spring is near and urge the plants to begin developing flower buds and leaves. And finally, mulch keeps the soil frozen once it freezes to prevent the cycle of freezing and thawing that can heave roots out of the soil and break them. Apply the mulch evenly over the flowerbeds. Keep mulches about four inches away from the trunks of trees and large shrubs to prevent mold or rot developing. Mulch protects the roots not the stems of plants, so the plants do not need a collar of mulch next to their bark.

Inorganic “mulches” are decorative substances such as rock, brick or landscape cloth. These are permanent mulches that are difficult to remove or alter without totally digging out the plants and the mulch. They are seldom applied deep enough to provide the protection of mulch.

Organic mulches do lovely things to the soil! During the growing season, mulch’s primary purpose is to cover the soil to prevent weed seed germination. Then it acts to slow soil water evaporation. It breaks down during the season to enrich the soil. What are organic mulching materials? They can vary as widely as a bunch of randomly placed conifer boughs (not very effective) to composted garden waste.

Most kinds of leaves can be mulched. English walnut leaves are a mulch material. Do not use black walnut tree leaves that contain a growth inhibitor. Rose leaves can be problematic because the thorns can take years to break down, and you want to avoid puncture wounds in the garden. During the summer, grass clippings can be spread out to dry and store to be mixed with chopped leaves in the fall. Most garden materials chopped up in a shredder can be used as mulch combined with other organic materials such as straw. It is best not to use hay since the grass seeds could germinate in the flowerbed

Large leaves, and leaves with waxy surfaces such as oak or sweet gum leaves, should be chopped up. Chopping leaves with the lawn mower makes the leaf surfaces smaller so they compost more rapidly. In addition the smaller particles of leaves do not form big, gooey mats and they do not blow around as large, entire leaves do.

Pine needles and cedar and fir needles are perfect mulch since they don’t matt down and leave air spaces that modify the soil temperature. And, no, they will not acidify your garden soil. The most important fact to remember is that depth is more critical than material. Mulch needs to be applied five inches deep to suppress weeds, maintain soil moisture and prevent frost heaving. Sometimes, the mulches break down rapidly and need to be reapplied during the season. Fortunately, last winter, I had stored extra mulch made of ground-up straw, leaves and grass clippings under a tarp. The weather last winter was warm, so the micro-organisms broke down the mulch. On a sunny February day, I re-applied the mulch back to its five-inch protective depth.
Happy plants means happy gardening!
By Bonnie Orr

Strange-looking Fruits and Veggies – 10/1/2021

– Every now and again our gardening eye is caught off guard: My, what is this? Mike Adams shared one of those moments with all of us when he emailed the strawberry picture here. Indeed, his strawberry did look other worldly. The phenomenon is known as vivipary (from the Latin, “live birth”). This happens when seeds germinate prematurely while they are still inside or attached to the parent plant. It is more com-mon in corn, tomatoes, peppers, pears and citrus fruit – rather rare in strawberries.

So why does this happen? Seeds contain a hormone that represses germination until conditions are favorable for the seed to germinate into a new plant. But sometimes the hormone is tricked into thinking conditions are right. And that’s what happened to Mike’s strawberry! He could have harvested and planted those seeds to see if a new plant would grow, then eaten the strawberry itself as its taste and texture were not likely affected.

Another interesting plant growth phenomenon is plant fasciation. The Pacific Northwest Pest Management Handbook describes fasciation as “a distortion of a plant caused by an injury or infection that results in thin, flattened, and sometimes curved shoots.” Abnormal flattening of the plant organs, usually stems, resulting in ribbon like, coiled or contorted tissue. The growing tip or apical meristem, which normally produces cylindrical tissue, be-comes elongated – oops plant mistake! According to Hortsense, leaf shape is not usually affected, although they may be smaller than normal.

Some suggested causes of fasciation include hormonal, genetic, bacterial, and environmental (physical injury). As long as the fasciation isn’t bacterial, trim it out and garden on. Or keep it as is as a unique plant form. If it is disease-based, proper sanitation protocols are called for.
Fasciation is fascinating! By Linda Sarratt

Successful Squash Plant Pollination – 7/1/2023

– Squash plants, a staple of home vegetable gardens, put forth many large, lovely flowers in early summer. But most of these flowers will never develop fruits because, for all their beauty, the flowers are botanically imperfect. Perfect flowers have both male and female parts. The male parts (anthers) produce pollen and the pistil (female part) receives pollen that fertilizes the ovule so fruit can develop. Tomatoes, peppers and eggplants have perfect flowers, so every flower can fertilize itself and produce a fruit.

The imperfect flowers of squash plants are either male or female. A male flower produces pollen which must be transported to a female flower for fertilization. Home gardeners often wonder why so many flowers on their squash plants die without producing fruit. While there may be a problem with lack of pollination or abortion due to excess heat, most likely the dying flowers are males that have already done their duty. Most squashes produce about 50% male flowers. Frequently they produce more males early in the season, frustrating impatient gardeners. Bees must do the work of pollinating squashes. Honeybees often visit squash blossoms, but native squash bees (Peponapis and Xenoglossa) are more efficient. They start early in the morning, before honeybees are active, and may get the job done before honeybees arrive. Before honeybees were introduced to the Americas, squash bees were the primary pollinators of squashes.

A close look will tell you if a flower is male or female. If the base of the flower is a straight stem, then it is male. Female flowers are usually larger than males and have a swollen base with a bulb that looks like it could develop into a squash fruit. If you look inside the flowers, you will see other differences. Inside the male flowers are several stamens that hold pollen. By contrast, inside the female flower is a large central structure which is the pistil. To be sure that squash flowers are pollinated, avoid using insecticides during the flowering period. Squashes are in the genus Cucurbita, which includes summer and winter squash, pumpkins, zucchini and gourds. All of the species in this genus can cross pollinate, so if you plan to save your squash seeds for planting in the future it is a good idea to hand pollinate your female flowers. Otherwise, the busy bees may cross your zucchini with a pumpkin, or your butternut squash with a gourd. You can use a small brush to move pollen from a male flower stamen to the tip of a female flower pistil, then cover the female flower with a fine mesh bag until the fruit has set. Squash blossoms are edible, so you can fry your early-season male flowers with chili and cheese if you don’t need them for pollination.
*Bush, Michael and Combe, A.K. Growing Squash in Home Gardens. WSU Extension Fact Sheet FS087E, 2013.
*Cane, Jim. Squash Bees. Pollinator of the Month. USDA Forest Service,
*Porter, John. Sex and the Single Squash. Garden Professors blog, 2018,
By Connie Mehmel

Systemic Pesticides in Fertilizer – A Cautionary Tale – 6/1/2022

In April during a planting demonstration at the CEG, concern was raised about the use of a fertilizer that contained a systemic pesticide and the effect it might have on pollinators, mainly bees. A similar issue arose in 2021 in the rose garden. These experiences prompted us to do some research on the problem.

Bees are important pollinators in home gardens and to the local fruit industry. Many factors have contributed to declines in the bee population. The main cause of this has been the Varroa mite (Varroa destructor) which was introduced to the U.S. in 1980’s. However, research has shown that use of systemic pesticides is also contributing to the decrease of these important pollinators.

Systemics are the most widely used pesticide because of their low toxicity to humans and animals and their ability to move through the plant. They are soluble in water, absorbed by a plant and moved around in its tissue. Because they are usually applied to the soil, some fertilizers also contain a systemic pesticide. Some systemics contain a group of chemicals called neonicotinoids (“neonics”). This group of chemicals affects the nervous system of insects that come in contact with them. In bees, high enough concentrations can cause death. They can also have sub-lethal effects such as affecting the bees’ ability to navigate back to their home, making it hard to groom themselves, increasing their susceptibility to disease and mites, and weakening their immune system. Of these chemicals, imidacloprid, thiamethoxam, clothianidin, and dinotefuran are very toxic to bees while acetamiprid and thiacloprid have a lower toxicity level for bees.
Since bees visit many different flowers throughout a day of foraging, they can be exposed to a combination of pesticides that may pose a varying degree of risk. Further research is being done to determine how these chemicals and/or combination of other pesticides are affecting our pollinators. One WSU publication suggests that although their re-search showed that the bee colonies they studied did not have chronic expo-sure to neonicotinoids, people should be careful when using them to avoid the risk of acute exposure. In addition, they should not be used when plants are flowering.

If a pesticide is necessary, use a systemic only if necessary and not on flowering plants. Check the la-bel on a fertilizer before purchasing it to see if it contains a pesticide. Use a product with the lowest toxicity to bees and follow all the instructions on the label. Spot spray the pesticide and never spray flowers or buds. Also look to see if beneficial insects are present and wait to see if they will control the problem pest. Spray when bees are not active such as at dusk or early morning and control drift. Consider adding native or eco-appropriate plants that are a good source of nectar and pollen for bees and do well without the need for pesticides. Regardless of the pest, remember to follow the principles of IPM.
By Diane Lee & Casey Leigh

Tips on Growing Blueberries – 5/1/2018

The plant clinic’s first berry questions of the season have been about blueberries– e.g., when to plant, whether to fertilize, types that grow well here, and light requirements. All are good questions, for which we had answers, plus a little extra advice!
Now is the time to set out the blueberries you bought at this year’s MG plant sale or acquired elsewhere. They do best planted in well-drained, porous, acidic soil in a sunny location, but will still produce berries if in partial shade. Blueberries should not be fertilized their first year. After that, fertilize once in the spring with a fertilizer designed for acid-loving plants. Add 4” of mulch around the plants (but not touching them) to protect the plants from our summer heat. The following advice is often the hardest to follow: Don’t let your plants set fruit for the first year so they can put their energy into healthy root development. To do this, pick the flowers when they appear. Failure to heed this advice will result in berries of lower quality and lesser quantity.
Many types of blueberries thrive in our area, e.g. ‘Berkeley’, ‘Blue crop’, ‘BlueRay’, ‘Elliot’, and ‘Jersey’. Select varieties that produce fruit early, mid-season and late season for treats all summer long. Be sure the plants fit into your landscape. Fortunately, blueberries come in many sizes: short, mid-sized, and tall.
Mature plants should be pruned in early spring to remove broken stems and to keep the plant’s structure open. As shallow-rooted plants, blueberries need the soil to be uniformly moist around the base. During our hot, dry summer months, they could need as much as 1-2” of water each week.
If taken care of, your blueberries will provide you a bounty of delicious fruit throughout the season and be-yond if you freeze them. If you feel the urge, bake some blueberry scones, or perhaps a pie, and drop them off at the plant clinic. I guarantee they won’t go to waste!
By Casey Leigh.

When and How to Harden-off Seedlings -5/1/2023

-You have put in the work to start your seeds and have trays of beautiful seedlings waiting to be planted in your garden. What next? You and your seedlings need to go through one more step — hardening off.
Hardening off is the process of toughing up your seedling so it’ll be able to adjust to life outdoors. Although it’s not difficult to do, it involves planning. You don’t want to start too early, or you will run the risk of cold temperatures damaging your plants. If you wait too long, your plants may suffer from becoming root bound.

Hardening off acclimates indoor-grown plants to outdoor conditions. The difference between indoor and outdoor temperatures is the primary reason for hardening off seedlings, but not the only reason. Wind is another natural phenomenon the seedlings need to be able to tolerate as well as full sunlight. Humidity levels also differ between indoor and outdoor areas.

An essential plant organ is the cuticle, the thick waxy outer layer that protects plants from harmful UV rays. The waterproof cuticle also helps the plant maintain its internal moisture levels. If you skip the hardening off period, you weaken the seedling’s ability to tolerate changes in temperature and withstand the sun’s UV rays, which results in less immunity to disease and pests.

Give your seedlings at least two weeks to make the transition to their new environment. Know when your average last frost date is and you can start transitioning the seedlings one week before that date. Find a lo-cation that is protected from animals, insects, and birds. An ideal location would be on an elevated location such as a table. Choose a location that offers dappled sun or partial shade. Then towards the end of the first week, expose your plant to full sunlight. Your seedling will need to acclimate to wind and airflow, also. If the day is particularly gusty, don’t put seedlings outside or use a wind block. Reduce the watering frequency to slow plant growth before transplanting. Get into the habit of watering deeply two to three times a week rather than daily. Allowing the soil to just barely dry out between watering will encourage a stronger root system and your plant will transplant better.

Begin thinking about hardening off once the plant has developed its second set of “true leaves.” As seedlings mature, they produce leaves that are typical of the species. These leaves usually come three to four weeks after germination. Once the true leaves appear, it is time to start the hardening off process. This process can take up to two weeks.

Step 1. Place seedling trays outside for a couple of hours with indirect sunlight. Bring back indoors before evening temperatures drop.
Step 2. Leave seedlings out a little longer each day, working up to six hours of direct sunlight and a light breeze.
Step 3. Leave plants outside overnight after risk of nighttime frost has passed.
Now plants are ready to transplant to their permanent locations.

For additional helpful information, read the WSU publication Propagating Plants from Seed
By Diane Lee

Winter Vegetable Gardening – 9/1/2013

It can be done without a lot of hassle, expensive equipment or taking up much space.

With a little protection such as cold frame or clear plastic hoop tunnel, cool season crops do just dandy when positioned for maximum sunshine with southern exposure. With a bit more warmth and protection, plants pretty much just take care of themselves–just about forget watering, hardly an insect around, little maintenance. Wow, a slower pace than summer gardening!
Emilie Fogle of East Wenatchee reports great results growing spinach, lettuce, kale, mustards and broccoli.
She made a compact hoop frame by pounding 1 foot pieces of rebar in the ground, spaced every 1 1/2 feet on the sides. Lengths of 1/2 or 3/4 inch somewhat flexible plastic pipe forms an arch and is anchored by pushing each end over the rebar. Fogle’s hoop house is five feet long, four feet across and only one and a half feet high. She covers it with a winter weight plastic row cover held secure with clips made for this purpose (clips were her largest expense for the entire project).
She also has a small cold frame…she says it was cheap and bends out of shape easily. She would invest in a stronger one if she were doing it again.

Sources for row covers, clips, cold frames and such include Territorial Seed Company, Grower’s Supply, Charlie’s Greenhouse and many other easily found on the Internet. Rebar and pipe are available locally from many sources.
Hurray to Fogle for keeping a detailed year to year journal, including planting and harvesting dates, soil and air temperatures, varieties planted and what was good or bad.
“I’ve always had great results with Bloomsdale spinach but any variety would do well. Same goes for kale and mustards,” she says. “I’ve planted Winter Red kale and Winter Density lettuce.”
“I like ‘Calabrese’–sprouting broccoli because it gives me numerous side shoots which allows me to use a few at a time in salads, etc.” says Fogle.
A freeze or two improves flavor of parsnips and carrots, as their starches change into sugar.

September is the time to set about preparing for overwintering vegetables. Our average frost date is mid-October, so count back from the days needed for your particular crop to mature, including seed germination time. Some plants will do best trans-planted rather than starting from seed.

Radishes are among the fastest to mature–30 days plus a week or so for seed germination, while broccoli and many brassica crops will germinate in a week or two but then require two to three months to grow enough before cold slows them down. Sprouting broccoli takes more time, also tolerates more cold, and must overwinter before forming a head in late winter. After the center is cut, side shoots just keep providing more broccoli.

Peppery arugula, hardy corn salad, mesclun — all are easy, dependable greens for winter months. Even a lettuce variety named Drunken Woman Frizzy Headed! Might be worth a try just because of its name!
By Mary Fran McClure



Best Bets for Houseplants -12/1/2016

– Bonnie Orr has compiled a list of houseplants in various categories that can help us make the best choices for our homes. Let’s start with flowering plants: Hoya, Lipstick, Christmas/Easter cactus, Peace lily, Begonia, Gardenia, Cyclamen, Hibiscus, African Violet, Citrus species, and Jasmine.
Next are the two lists I need most. First, easy plants: Sansevieria, Spider plant, Palm, Devil Ivy, Philodendron, Christmas/Easter cactus, Dieffenbachia, Shamrock, Wandering Jew, Peace lily, Aluminum Plant, Asparagus Fern, Grape Ivy, Swedish Ivy , Sedums, Cast Iron Plant, Begonia, Aralia, Prayer plant, Rubber tree, Velvet plant, Croton, Ti plant, Piggyback plant, Peperomia, Snakeskin, and Chinese evergreen. Note that some of these easy plants are also in the flowering plant list! Second, difficult plants: Ferns, Polka Dot , Fig, Norfolk Island Pine, Gardenia, Cyclamen, Hibiscus, Bougainvillea, Kalanchoe, African Violet, Mandevilla, Coleus, Caladium, and Copper Leaf. I like this category – messy plants: Ferns, Lipstick plant, Begonia, African Violet, Rosary Vine and Mother of Thousands. Fortunately this is a short list!
Finally, we have low-light plants: Chinese Evergreen, Aspidistra, Baby tears, Dracaena, Elephant ears, Iron Cross Begonia, Ivy, Maidenhair fern, Palms, Peace lily, Peperomia, Philodendron, Polka Dot plants, Devil’s Ivy, Rabbit-foot Fern, Sansevieria, and Ti plant. Enjoy your indoor plants! By Casey Leigh

How to Care for Your Christmas Cactus – 12/1/2015

Although not as common, questions about houseplants are brought to the Diagnosis Clinic. For this month’s article, we decided to give information about a houseplant that often appears in stores in the late fall: the Christmas cactus, a popular houseplant brought from Rio de Janeiro in 1840. Dozens of species exist, and they bloom at different times. A short description of the plant will help a home gardener grow this plant successfully. In Brazil, the cactus grows as an epiphyte—that is, it grows on the branches of trees solely for physical support, taking its nutritional needs from the air and rain. The plant produces profuse elaborate blooms based on the change in the number of hours of light. Because we are at the 47th parallel, we have a dramatic change in the number of hours of daylight. This makes for perfect timing for this plant to bloom for Thanksgiving or Christmas.
Christmas cactus suffers when the temperature is less than 55 degrees. In late May, I take this potted houseplant outside to a place with bright, indirect light on the northeast side of my house. Remember, this plant’s ancestors lived on the shady branches of trees in Brazil. Water and feed it regularly with a low nitrogen fertilizer. In September I bring it back into the house. If you purchase one from a store at this time of year, be sure to have the clerk wrap it securely in several plastic bags and hurry home with it. Or, propagate it yourself, as it is easy to do so. If you see a plant you like, ask your friend for two or three joints of the petiole. Let it dry for a day or so, then place it in seed starting planting soil. Water the soil well. Cover the pot with plastic wrap and place the pot in bright indirect light. Do not water it again until the plant shows signs of new growth. NOTE: You have made a commitment. The plants can grow for generations. I know people who have inherited them.
The traditional Thanksgiving cactus has little horns on the petiole (leaf). The Christmas cactus has smaller petioles that are smooth and rounded. The plant has been hybridized to produce huge, complex flowers. The color spectrum ranges from pale orange to vibrant pink to shocking red.
• How to get the plant to bloom. Stop watering the plant in September. As the light lessens, the plant will put out flower buds. Watch for them carefully; water the plant well when they first appear.
• Then water once a month. If you water too frequently, the flowers and the buds will fall off (Does this sound familiar?) It does not need very much water. Over watering is the main cause of this plant’s death.
• A 65-70 degree room is best for the plant.
• When the plant’s flowers have faded, water and fertilize lightly. Then continue to water once a month until it is time to take it outside again.
During these short days, the cheery blooms of these cacti are a welcome color. Enjoy yours as much as I enjoy mine. By Bonnie Orr

Low-light Houseplant Care – 12/1/2017

We have entered our low-light phase of the year—that means lots more time to curl up in front of the fire to read a good book. We will enjoy that—but our houseplants will not be as contented.
This week my portable houseplants returned from summer camp. Well not really, they just spent the summer in the fresh air on the north side of my house. They grew in natural light, and their leaves were regularly washed with the sprinkler. The venerable houseplants—mostly over 30 years old—are too big to move outside, but I moved them to a brighter window for the summer.
All the houseplants were fertilized once a month. The best time to fertilize is when they are growing rapidly in great conditions. The plants can utilize the fertilizer, and there is not accumulation of excess salts. More importantly, when the plant is growing in good conditions, the plant’s growth is vigorous and healthy. In low light conditions, growth forced by fertilizer is usually wimpy and succulent—just what the sucking insects ordered!
If your plants did not summer outside, a sane fertilizing schedule follows the seasons. For the spring equinox, provide fertilizer at ¼ strength (the water will barely be blue). For the summer solstice, fertilize at ½ strength, and for the autumnal equinox, fertilize at ¼ strength. Do not fertilize at the winter solstice since the inside light is barely strong enough to support plant growth. Of course, if you use grow light, you can fertilize at ½ strength for all the seasons.
This is the time of year to prune back unruly houseplants to get them ready to be admired by holiday guests. Get rid of dead leaves or long stringy growth. Then give you plants a shower—either in the bathroom or by placing plastic on the floor and gently squirting the tips of the leaves of large plants. We live in a windy, and often smoky, area, and you will be surprised how much dust is washed off the leaves of the plants. The plants need clean leaves for two rea-sons. First, light is essential for photosynthesis. A dirty surface reduces the amount of light that reaches the leaves. More importantly, dust is a hiding place for insects, especially red spider mites that love hiding the in the dust that provides anchors for their minute webs.
This is also the season for tough love. If one of your plants has been languishing for several seasons and has never regained its vigor, toss the plant out. I know this is hard. Twenty years ago I planted a coffee bean and have been nourishing my coffee tree, but it has become a magnet for scale insects which can rapidly infect every nearby plant. So I kissed it goodbye at the compost bin. It was difficult, but if I can do it, you can do it. One of my Christmas cactus has been limping along for the past year. The compost worms are enjoying that plant as well.
If you bathe your houseplants, fertilize moderately and eliminate the weakened plants that will become susceptible to insect infestations. Now you should have more time to sit back and read! By Bonnie Orr



Fall Lawn Thatching – 9/1/2017

While most people think of spring as the time to thatch a lawn, fall thatching is equally effective and has the advantage of reducing the spread of weeds with the upcoming winter cold. Thatch removal should not be done in late spring or during the summer.
What is thatch and why is it a problem? Thatch consists of both living and dead stems, roots, rhizomes and leaf sheafs. It is a normal process of lawn development and if not excessive, is beneficial. Healthy thatch is less than ¾ of an inch thick, protecting against soil compaction and the effects of excessive hot and dry weather on grass. Once thatch becomes too thick, it prevents the grass from being able to effectively take up water and nutrients needed for healthy growth and development. A weakened lawn makes it more susceptible to developing weeds and to insect damage. During the hottest part of summer, lawns with too much thatch develop dry spots.
If the thatch is less than two inches thick, it can be removed with a power rake or vertical mower, thereby saving you from having to replace your lawn. WSU has some helpful publications on the process of de-thatching if you choose to do so yourself rather than employing a professional landscaper. By Casey Leigh

How to Care for Your Lawn – 6/1/2014

I love lawns, green lawns; make that a beautiful expanse of a uniform emerald carpet. I like them manicured along the edges for a nice crisp look along a sidewalk and driveway. One problem—the Wenatchee Valley is not located in Ireland, where emerald green grass seems to grow without effort. So the question for each homeowner is: Do you want to make the effort for such a lawn? Or would you rather have a lawn that is a little more on the wild side? It really can be a matter of personal preference. It is possible to have either with a little planning and consistent applications of gardening principles.
All plants need three things to thrive—water, nutrients, and sunshine. All these things need to be in the right amounts for optimum plant health. So how do we get it right for lawn grasses in our area?
I received my first hint on watering in north-central Washington when I took the boy scouts camping in the early 1990’s at Sun Lakes State Park. The grass we camped on there looked great but I didn’t know when they would water with all the tents and camping equipment that I saw in the park. I asked the ranger when they watered and his reply surprised me, “Tuesdays.” That’s right, a place in the desert with summertime high temperatures near 100°. They water once per week deeply and the grass roots can get water all week long as they grow downward.
I went right home and changed my sprinklers from the 10 minutes every day setting I inherited when we bought our house. I set out empty tuna cans around my lawn and timed how long it took to fill them up. That is how much water a healthy lawn needs in a week. I set my timers for the new, longer watering cycle and changed to once/week. This will de-pend upon your soil texture. Some soils won’t absorb the water all at once and it may need to be applied in more than one cycle of your sprinklers. If water is running off your lawn it is watering something other than your lawn. I had to start this in the spring so it’s not too late to start this year.
Improper watering is a major cause of unsightly or damaged lawns. Light, frequent sprinklings encourage shallow rooting of turf grasses. Shallow rooted turf cannot withstand sudden changes in temperature or soil moisture. Overwatering can cause soggy conditions and may (1) leach plant nutrients, especially nitrogen; (2) encourage weeds such as speed-well, buttercup, and annual bluegrass; and (3) cause oxygen starvation of the grass roots.
Our soils in north-central Washington are typically adequate in levels for phosphorus and potassium and we usually only need to add nitrogen. Nitrogen is the first number of the three numbers found on every bag of fertilizer. Our turf grasses here need nutrients most in the spring and late summer/fall when they are most actively growing. Nitrogen pro-motes strong vigorous growth of grasses. Use a fertilizer with at least 30% slow release nitrogen, slow release fertilizer since it feeds the grass over time rather than all at once. (You’d rather eat every day than down your whole month’s calorie supply in one sitting, right?) Read fertilizer label thoroughly and apply at the rate recommended on the label.
Weeds don’t cause an unhealthy lawn. An unhealthy lawn causes weeds. Most common causes of unhealthy lawns—under or overwatering, mowing too short, not feeding. We mentioned watering earlier.
I learned some time ago that raising the mowing height promotes a much healthier lawn. The taller grass shades the soil and prevents many weeds from being able to grow. It keeps the soil cooler and that reduces evaporation and the need to water as often. It also keeps more of the green part of the plant that uses the sunshine (abundant in our area) to make food for the plant. It may surprise you that more than 90% of the weight of the grass plant is in the crown and roots. More leaf area means more root growth possible and healthier plants. I also use a mulching mower and leave the grass clippings on the lawn. As they break down they slowly release nutrients into the soil, helping to feed the lawn and keep it healthy. It can reduce fertilizer use by ¼, so you save money as well!
Applying these principles remarkably reduced the weeds in my lawn and now a little spot weeding is all that is needed. If you don’t mind a more varied lawn texture, there are some great seed mixes for lower maintenance lawns that are well adapted to our climate.
If you want more info on healthy lawn practices and options, please contact the Master Gardeners. By Rob Merrill

Lawn Care & Maintenance – 6/1/2021

The Clinic receives a myriad of lawn questions from spring through fall. In anticipation of that, I re-read WSU’s excellent “Home Lawns” publication (EB0482E). Here are some highlights.
First, what are the best turf grasses for our area? Kentucky Bluegrass works well here either as a monostand or in a mixture with other grasses. Four types of fescues are also appropriate, usually in mixes: red, Chewings, hard, and turftype tall.
Proper fertilization is key to a healthy lawn. A properly fertilized lawn cuts down on both disease and weeds. Nitrogen fertilizer is the most common need in eastern Washington. A soil test done every 3 years is the best way to find out what your lawn needs. WSU recommends that Washington lawns get 4 pounds of nitrogen per 1000 square feet per year, divided into four equal applications throughout the season. Fertilizers are labeled either quick release or slow release. Soil type, turf grass species, use and maintenance level are factors to consider when choosing which to use, or a combination of the two.
Keeping the blades on your lawn mower sharp and mowing at the correct height for the type of turf grass in your lawn are critical factors in lawn maintenance. Mowing your grass too close to the ground will stress your lawn, making it more susceptible to disease and insect damage. Check the recommended mowing height for the type turf you have.
A common lawn myth is that leaving the grass clippings on the lawn after mowing will cause thatch to accumulate. To the contrary, lawn clippings are good for the lawn by returning nutrients, as long as the amount of clippings isn’t excessive. For aesthetic purposes, WSU recommends mowing the lawn twice a week or more if you don’t re-move the clippings.
Two common lawn maintenance practices are thatching and aeration. Thatch is a layer of old roots and stems that accumulate between the zone of green vegetation and the lawn surface. When it becomes too thick, the lawn thins out. Special machines are available to remove thatch. For best results, thatch in late winter or early spring once the ground is no longer frozen, or in late August. It may be necessary to over-seed if your lawn has become too thin. Aeration is used when your lawn soil has become compacted. When done properly it allows for better water and air penetration. As with thatching, special tools are used for aeration.
By far the mistake we observe most often in clinic is improper watering. On average, turf needs about 1 1/2 inches of water per week or enough to moisten the soil to a depth of 4-6 inches. To measure this, we suggest the tuna can method, which lets you know how much time it takes for a measured volume of water to penetrate your lawn to 4-6 inches. Start by setting out several tuna cans in the spray pattern, then run your sprinkler until the cans have an average of one inch of water. Note the start and stop time. After 24 hours, measure how deep the root zone is moistened. If you run your sprinkler for 30 minutes and the sample you dig is only moistened three inches, then you need to water longer. Or if your soil is very sandy and the soil is moistened beyond the root zone, adjust your watering to less time and more often.
Following the above should result in a beautiful, healthy lawn. By Casey Leigh

Preemergence Herbicides– 3/1/2022

Ahh! March. A month to curl up by a warm fire, sip your favorite warming beverage, and look at seed catalogues as you dream about spring when you will be able to get out into the garden in person. But wait! As you dream about your garden of the future, do you also have nightmares about weeds? Give a weed in inch and they will take a yard. Weeds! Those pesky plants defy our efforts to wipe them out. What’s a gardener to do?
One answer is the use of preemergence herbicides. Preemergence herbicides prevent germinated weed seedlings from becoming established either by inhibiting the growth of the root, the shoot, or both. Preemergence herbicides do not kill the weed seeds themselves. They stay in the soil for a while and prevent the weed seedlings from becoming established. The use of preemergent herbicides may provide a foundation for season-long weed management, along with tilling and other good gardening practices.
The use of preemergence herbicides requires careful thought and planning. Dr. Rebecca Grubbs-Bowling, assistant professor and turfgrass specialist at Texas A & M University, says that timing is the secret. The soil temperature should be in the 50–55-degree range. Exactly when your soil is the right temperature will depend on your local climate, and what the weather is like this season (Bowling, Rebecca ( “Timing is Critical”). Dr. Grubbs-Bowling has published a helpful article entitled “A Homeowner’s Guide to Herbicide Selection for Warm-Season Turfgrass Lawns” that is available through Texas A&M Extension ( Soil moisture will also impact the success of a preemergent. Most preemergent herbicides must receive rainfall or irrigation to work well. In addition, understanding the life cycle of the target weed is a must in order to control the weed that is the bane of your existence. Careful selection of a preemergence product that is specific for the weeds you wish to eradicate is necessary. Preemergent herbicides used to kill weeds in lawns will be different than those used to control weeds in other parts of your garden. Preemergent herbicides that control grasses and a few broad-leaf weeds may injure many ornamental plants. Caution is needed when dealing with all herbicides!
Read the label of the preemergent herbicides carefully and follow the directions exactly. Most preemergence herbicides will last between 8 – 12 weeks. Reapplication may be necessary. Again, timing is the secret. It does no good to reapply a preemergence herbicide after the weed seed has already germinated and gained a ‘root-hold.’ There are many reputable publications focused on specific weeds and recommended methods of control in addition to pre-emergents. As always, be sure the information you turn to comes from reliable sources such as the extension services of schools of agriculture like Washington State, Oregon State, or Idaho State Universities. These extension services offer helpful publications on the control of specific weeds.
With spring only a few short weeks away, we will soon be in weed-tackling mode. Uses of preemergent herbicides can help lessen the burden of weeding later in the growing season. By Pat Beeman

Snow Mold– 2/1/2019

I first heard of snow mold when I was a kid and people with allergies were naming it as the cause for their symptoms. My most recent experience with it was at Rocky Reach Park in the late winter of 2017. It wasn’t widespread and seemed to occur where the snow was the deepest or took the longest to melt away from the lawn. We didn’t apply any treatment other than using the back-pack leaf blowers to “fluff” up the turf and expose the new shoots to the sun and air.
If we finally get a good covering of snow this year, we may get questions in the Plant Clinic about snow mold. Here is an overview that should help with correctly identifying and recommending preventive measures for it.
What is snow mold and what causes it?
Snow mold is a fungus. The two most com-mon are either pink snow mold (Microdocium nivale) or gray snow mold (Typhula incarnata, T. ishikariensis and T. idahoensis). They both like the cool, moist conditions found under deep snow. It is most prevalent when lawns have been fertilized late in the fall or where thatch is present and where snow is present for extended periods.
It presents itself as circular patches on turf grass. These can be irregular and can merge to cover quite large areas. The turf will be matted and when wet you may see the dense whiteish to pink threads (mycelium) for pink snow mold or blueish gray to almost black mycelium for gray snow mold. The following website has good photos of snow mold:
How do you treat snow mold?
The affected areas should be raked to expose the new growth to light and air. It should be noted that this disease rarely kills the grass.
How do you prevent snow mold?
To control these fungi, certain management practices can be followed in the fall that will normally be adequate. Mow as long into the fall as the grass is still growing and keep leaves and grass clippings raked off the turf. Don’t apply too much nitrogen fertilizer late in the fall. Good surface drainage and controlling thatch is also helpful.
Although there are fungicides that can be applied preventively in the fall, WSU does not recommend doing so on home lawns because turf usually recovers once the weather changes. By Venessa Martyn

Why Your Lawn Doesn’t Look so Good – 9/1/2018

It is mid-summer, and our lawns are not looking as good as they did in June. There are many reasons for this. First of all, we have had many days in the 90’s. It is another “cooler” summer because we have not experienced many temperatures in the 100’s; however, it has been really windy all spring and summer, and the relative humidity has hovered around 20 percent. The wind and the low humidity, more than the temperature, influence the evaporation rate. With the conditions we have experienced, some days the evaporation rate has been as high as ½ an inch. So, most likely, there are some dry spots in your lawn. What are the reasons besides Mother Nature?
The most likely reason is uneven water distribution from the sprinklers. It is not too late to put out the string of tuna cans to monitor exactly how much water in a variety of locations is being laid down each time you run your system. You can then adjust your sprinklers. Dry spots could be the result of shrubs or perennials growing in the spray line of a nozzle, so run the system and look for problem areas.
The next reason for a wan lawn is mowing practice. If you mow your lawn at less than 3 inches in height, the crowns of the grass plants can be burned by the hot summer sun. This causes brown patches in your lawn as well.
The most common cause of a weak summer lawn is the underlying soil. The effectiveness of watering and fertilizing your lawn depends on the soil it is growing in. In sandy soils, the water goes straight down and does not spread out to water adjacent areas of roots. So sandy soils can require water more frequently. Clay soils, on the other hand, allow the water to move sideways; however, clay soils may not readily release sufficient water from its reserves for use by the roots due to clay’s natural physical tendency to hold water.
So what other lawn issues have diagnosis clinicians talked about with clients this summer? The classic is crabgrass, which was not controlled with a pre-emergent applied at the correct time in the spring. But, hey, it is at least green! Creeping bent grass is harder to deal with. This invader that grows in tight circles and overwhelms the Kentucky blue-grass is nearly impossible to control unless you are willing to dig out each clump by hand. Interestingly, golfers seems to have more of this in their lawns because bent grass is used on golf courses, and the seeds are picked up in golfer’s shoes and equipment.
Sod web worms, doing their damage unseen at night, eat the roots of grass plants. This creates patches of dead turf that easily pull out of the soil. Sod web worms are larvae of the lawn moth. Hortsense suggests two types of non-chemical management. The presence of birds, ants, spiders, and predacious ground beetles, natural enemies of sod web worms, helps keep them in check. Also, keep your lawn thatched as sod webworms are attracted to thick thatch. Hortsense lists a few pesticides legal in Washington that can be applied at the larval stage to reduce populations.
Of course, the long days and the heat have caused the fescue grasses to go dormant and create some browning. The good news is that the fescue will regrow in September just as the Kentucky bluegrass is beginning to go dormant. September is the best time to put in a new seeded lawn. The soil will be warm enough for long enough for the grass roots to become established. And with the cooler September daytime temperatures, it will be easier to keep the germinating grass seeds moist enough to sprout. September is also time to rejuvenate your lawn by either thatching or aerating the turf.
By Bonnie Orr.


Pests and Diseases

Plan for the Attack of the Aphids – 4/1/2021

Spring is almost here! We can feel it in the air. While night-time temperatures are still cold, our days are beginning to warm up and as gardeners we are eager to get outside and GARDEN! But wait. It is much too early to be planting vegetables or flowering plants. What’s a gardener to DO? Plan for the Attack of the Aphids. While that may sound like a B-rated horror movie, aphids are horrible. Still, there are proactive steps to help protect our plants and gardens from these marauding insects.
Almost every plant has one or more aphid species that occasionally feeds on it. Low to moderate numbers of aphids aren’t usually damaging. However, large populations can quickly turn leaves yellow and stunt shoots. Aphids can also produce large quantities of a sticky substance known as honeydew. Honeydew often becomes the food source for a sooty mold fungus. Aphids may also transmit viruses from plant to plant on certain vegetable and ornamental plants.
Many aphid species are difficult to distinguish from one another; however, management of most aphid species is similar. Knowing the life cycle of aphids helps determine what needs to be done to take a proactive stance against these pests. Aphids have many generations a year. In our climate most aphids produce sexual forms that mate and produce eggs in fall or winter, producing a hardier stage that can survive harsh weather and the absence of foliage on deciduous plants. They survive winter by laying their eggs in the leaves and dead plant material that is under plants or the mulch used in gardens. Here is where the first step in a proactive attack against aphids starts. Clean up all dead material from around your plants and garden beds. Remove weeds, grass and plants that might be vulnerable to aphids. Preventing places where aphid eggs can be protected through the winter will go a long way to keep aphids from getting a foothold in your garden.
The adult females give birth to live offspring – often as many as 12 per day. In warm weather many species can develop from newborn nymph to reproducing adult in seven to eight days. Because each adult aphid can pro-duce up to 80 offspring in a matter of a week, aphid populations can increase with great speed. No wonder it can seem as if we suddenly have an aphid population explosion over night!
Once it is safe to plant vegetables and flowers outside, the second step to thwart aphids is to select plants that are least susceptible to aphids. Inspect plants that you buy carefully to make sure you aren’t bringing aphids home with you. Check the underside of the leaves where aphids will most likely be found. Keeping the number of aphids out of your garden and yard to a minimum is paramount. When there are only a few aphids present, it is easy to squish them gently against the stems or leaves with your fingers. Later in the season when plants are maturing, a sudden bloom of aphids usually can be knocked off plants with a spray of water. This may need to be done repeatedly over a period of time. Use of a mild soap and water spray can also help. If the aphid damage is on only a few leaves, pick off damaged leaves or prune to prevent further damage. To prevent rapid growth of soft, nitrogen rich tissue which is extremely attractive to aphids, do not over-fertilize with nitrogen fertilizer. Avoid over watering which can cause some plants to grow too rapidly. Protecting beneficial insects such as lady beetles, lacewing larva, soldier beetles, and certain species of parasitic wasps will go a long way to controlling aphid populations.
Most plants can survive a small infestation of aphids but if it becomes absolutely necessary to use insecticides do so very carefully. Use an insecticide that is specific for aphids. Follow the directions on the label. Remember that insecticides will also kill any beneficial insects which can provide natural control of aphids. If in doubt, don’t do it.
Or perhaps you notice a congregation of ladybugs on a rose stalk. Don’t invoke the old nursery saying and ask them to fly away home. Their house is not on fire. Your roses are, with aphids, which the ladybugs are feeding on – and you can bless yourself that they have come to your rescue.” Author: Eleanor Perenyi
By Pat Beeman

Why the World Isn’t Knee-Deep in Aphids 6/1/2023

In late spring, when the light lasts longer and the days and nights warm up, aphids begin to emerge from their eggs. These aphids are all females. Once they reach adulthood, they disperse and begin to reproduce parthenogenetically, cloning themselves without mating. They are viviparous, so instead of laying eggs, their offspring are “born” rather than hatched.
The job of these aphids is to start new colonies. They are very good at what they do! A female aphid can live for about a month, and when resources are plentiful, will produce between 50 and 100 wingless offspring in her lifetime. In warm weather, it only takes about a week for newborn nymphs to reach adulthood, at which point they will also start cloning themselves. Just one adult aphid, then, could spawn a population of billions.
That many aphids could do some serious damage. Aphids eat by plugging their straw-like mouthparts into a plant. They go for the phloem, where liquid sugars made through photosynthesis are under pressure in the plant’s vascular system. They need to ingest a lot of juice from a plant in order to glean enough amino acids and nitrogen to thrive. If enough aphids are present, they can siphon off too much sap from their host, causing new leaves to pucker and curl and reducing the plant’s vigor.
Fortunately for the aphids, they have internal overflow valves for releasing some of the abundance of sap that squirts out of the plant and into their digestive system. Unfortunately for gardeners, the extra plant sap which flows out of the aphids keeps flowing, right onto the leaves of the plant. This sticky mess is called honeydew. Unless you are an ant, honeydew is pretty unappealing in the garden. It can also be a medium for sooty black mold which can block light and prevent leaves from photosynthesizing. It’s a good thing, therefore, that not all of the offspring from those first spring aphids will survive. They are easy prey for a long list of predators. Aphids are wingless, in most cases, until the fall mating generations emerge. Because their mouthparts stay injected into the plant, they are not able to make a quick escape. Their best defense is to secrete a warning pheromone out their cornicles when they are attacked, alerting others nearby to danger. Lucky aphids can fall off a leaf to escape a predator, but they can’t fly, jump, or even run.
The most famous aphid-eater is the ladybug, whose aggressive black and red larvae look and act more like crocodiles than caterpillars. Other natural enemies of aphids include syrphid flies, snakeflies, green and brown lacewings, earwigs, big-eyed bugs, damsel bugs, rove beetles, soldier beetles, ground beetles, praying mantises, and many species of tiny parasitic wasps. Aphids are food for many other animals besides insects, too. Spiders, lizards, frogs, toads, and even small birds feed on them, keeping their population in check.
The main reason aphids reproduce rapidly is to counter the fact that so many animals rely upon them for food. The best way to keep aphid populations low is to provide a healthy habitat for their predators. Using pesticides to kill aphids actually can improve their ability to multiply, since pesticides will also reduce the populations of their natural enemies. Because they have so many offspring, it is much easier for aphids to achieve resistance to a pesticide than it is for other species. In small numbers, aphids do little damage to well watered, healthy plants. Their presence invites a rich diversity of life into our gardens and yards.
By Julie Banken
Resources: University of Kentucky, Aphids, in depth – Wisconsin Horticulture, The Bug Chicks

Earwigs 9/1/2019

In my favorite insect garden book, “Good Bug, Bad Bug”, earwigs are labelled as pests. When they created ragged holes or chew marks along the edges of some of my favorite plants, I tend to agree. But when they munch on my unwelcome aphids and mites, I am happy to see them. Based upon the number of complaints about earwigs that have come into clinic this summer, it seems they have been more of a problem than in some years.
Most of us are familiar with the ¾ inch reddish-brown earwigs with their telltale pincers on the rear end. Females reproduce one generation per year, laying clusters of up to 30 eggs under rocks in the soil. The female actively tends the eggs, cleaning fungi from them and actively guarding and protecting them. The female, along with her newly hatched young, emerge in the spring and start feeding. They feed at night and enjoy a smorgasbord of many of our plants, such as home tree fruits, flowers like marigolds, zinnias and dahlias, and the seedlings of lettuce, celery, beets, and carrots, among other vegetables. However, they can also be beneficial in our gardens, eating pests such as aphids and mites and scavenging dead bugs and plant debris. Earwigs can fly, but rarely do. During the day they rest in moist, shady places and beneath boards and stones.
When feeding, earwigs create ragged holes in a plant’s leaves as well as chew marks around the leaf margins. The damage is similar to that created by caterpillars and slugs so you have to go out at night to see if earwigs are the culprit. In addition, they bore shallow irregular areas into the surface of fruit. Shoot tips fed on by earwigs often fail to develop and can result in stunted growth.
Hortsense does not recommend chemical methods of control. Instead, they suggest keeping your garden free of their daytime hiding places. You can also place rolled newspapers, burlap bags, or flat boards beneath the affected plants for both monitoring and trapping earwigs, as well as purchase commercial traps. Pick the earwigs out from under your “traps”. You can shake earwigs off flowering plants into a box lid or something similar. Biological enemies of earwigs include frogs, toads, predator beetles and duff-scratching birds.
So, if you see what could be earwig damage in your garden and have a bout of insomnia, step out into your garden with a flashlight and see if earwigs have set up housekeeping.
By Casey Leigh

Elm Seed Bug or Elm Leaf Beetle? – 8/1/2018

“Do you know the two insects above? Do you know which one is simply a nuisance and which one damages plants? Or which one is the beetle in the Coleoptera order and which is the true bug in the Hemiptera order? Both of these have been brought into the clinic in the past few weeks by concerned home gardeners. This article will answer those questions and give you helpful information about them in case you encounter them in your home or garden.
The insect on the left is the elm seed bug, Arocatus melanocephalus, a native of south central Europe. Chances are many of you have encountered this diminutive member of the true bug (Hemiptera) order, particularly if elm trees grow nearby. As the name suggests, the primary food of both nymphs and adults is seeds of the elm tree. Adult elm seed bugs emerge in the spring to mate and lay eggs during an extended egg laying. The nymph stage includes several molts, with the wings developing more through each molt until adulthood.
Being seed eaters, the elm seed bug rarely poses a problem in our garden landscapes. However, in July and August they can appear in large numbers outside on decks and patios, eventually finding the way into homes to escape the heat of summer, becoming an “instant” nuisance. This pattern is repeated in the fall when the adults look for overwintering shelter, and again in the spring when they emerge to begin the life cycle anew.
What can be done to deal with this pesky bug? First, monitor for adults and nymphs on the house siding, decks, and patios, or on seeds in the trees or on the ground. When you find adults congregating, vacuum them up as soon as possible preferably with a shop vac rather than your home vacuum because they produce an unpleasant odor when disturbed or crushed. Placing sticky traps on your windowsills also helps. Check to see that crevices and cracks where they can sneak into your house are caulked. In the fall, rake and dispose of elm seeds around the outside of your house. If you or your neighbor has elm trees, be attentive and inspect boxes, pots, firewood and the like before bringing them in the house. A broad spectrum insecticide can be sprayed around the perimeter of the house and at suspected entry sites to try to keep them out of the home.
The other picture is of the more destructive elm leaf beetle, Xanthogaleruca luteola, a member of the order Coleoptera. Approximately ¼” long, their dark stripes against a yellow background are distinctive. Their yellow eggs can be found clustered on the underside of the elm leaves. Similar to the adults, elm leaf beetle larvae are yellowish with black lateral stripes. Both larvae and adults feed on the leaves. Evidence of the presence of larvae is skeletonized leaves, while adults create small holes in the leaves. Serious infestations can cause premature leaf loss, weakening the trees, which opens the way for attacks by elm bark beetles that in turn carry the Dutch elm disease fungus.
Like the elm seed bug, the elm leaf beetle can invade homes seeking a protected place to overwinter. In spring the adults lay their yellow eggs and begin feeding. After feeding for a time, the larvae migrate downward where they pupate on the ground or in crevices near the base of the tree. The second of the two generations emerges a week or two later.
Cultural control options include planting elm leaf beetle resistant elm cultivars or trees such as the Chinese elm and the elm-like zelkovas. (You can find an example of a zelkova, the Zelkova serrata ‘Schmidtlow’, in the utility friendly tree section of the CEG.) The PNW Handbook cautions, however, that many of the cultivars are highly susceptible to Dutch elm disease. Prune dead and dying branches in late fall or winter. Hortsense lists pesticides legal in Washington that can be used to control this beetle.
If you’d like to see examples of each of these insects, we have both in our entomology collection at clinic. If insect identification and control interests you, consider joining our diagnosis clinic team!
*Most of the information for this article came from
By Casey Leigh

It’s Time to Treat Scale Crawlers – 6/1/2019

In recent weeks, clinicians have helped gardeners identify and learn how to treat scale. These diminutive insects are a common problem for several species of plants, including pines, fruit trees, maples, willows, lilacs, dogwood, rhododendrons, camellias, and houseplants, among others. Because there are approximately 8,000 species of scale and they attack such a variety of plants, most gardeners either have had or will have to deal with scale infestations.
Scale are true bugs of the Hemiptera order of piercing and sucking insects. They progress through three life stages of egg, immature, and adult, with several generations possible in a single year. During a significant portion of their lives, the insects live under a scale-like covering (hence their common name) that contact insecticides are ineffective against. These telltale scales are usually the evidence gardeners notice on the leaves, twigs, stems and fruit of their plants. However, there is a short window of time when the immature, or crawlers, emerge from the eggs and begin feeding. This is when they are most susceptible to treatment. And now is the time they will be moving around unprotected.
So how best can you monitor your plants for appearance of the crawlers? Check WSU’s AgWeathernet for local Growing Degree Days. When the GDDs reaches 707 based on a 50 degree calculating point, the crawlers should be emerging. Use your hand lens to check plants you think may have scale. You can also place doublestick tapes in areas where you see the hard scale shells to trap them when they emerge. An interesting suggestion by WSU is to put n infested branch in water and leave it outdoors in a shady place where you can check the scale eggs every few days for a hatch. Regardless of the method you use, once you see them crawling it’s time to begin treatment.
The presence of certain beneficial insects in your garden will help prevent an infestation. Birds, lady beetle adults and larvae, mites, and green lacewing larvae feed on the crawlers. Certain minute wasps lay their eggs in and parasitize scale. Because of this, avoid using broad spectrum pesticides. Because we have several species of scale locally that attack different plants, check Hortsense for insecticides specific to the type of scale feeding on your plants.
By Casey Leigh

Keeping Track of Insects and Plant Development: Growing Degree Days – 4/1/2019

Most Chelan/Douglas County Master Gardeners have been to at least one presentation on Growing Degree Days (GDD)taught by Paula Dinius. This article is a refresher on GDDs to remind us how to use this tool to track the timing of plant development and concomitant appearance of insects in our gardens. This knowledge, in turn, can be used to help with garden insect pest management. With spring on the horizon, now is the time to put that information into practice as insects will soon be emerging from winter hibernation.

For many of our plants and insects (both beneficial and harmful), certain stages of life, such as the appearance of flowers or the hatching of eggs, are triggered by a certain number of GDDs. GDDs, a measure of accumulated heat, are defined by the National Phenology Network as “the number of degrees the average daily temperature exceeds a base temperature, or the temperature below which the organism will remain in dormancy.” The base temperature we use here is 50 degrees.

A specific formula is used to calculate GDDs: average daily temperature minus the baseline temperature equals growing degree days gained. For example, if the average daily temperature for April 1 is 52 degrees (high temperature minus the low temperature divided by 2) and the base temperature is 50 degrees, then the accumulation for April 1 would be 2 GDDs. If on April 2, the average high and low temperature is 48 degrees, no GDDs are accumulated so the total number of GDDs on April 2 is 2.
This calculation should be done every day, adding each day’s total to the total of all previous days. So with the above example, if on April 3 the average temperature is 62, 12 GDDs are added to the balance of 2 GDDs from April 2, making the total cumulative GDDs at 14. Fortunately for us, that’s not necessary as WSU’s AgWeatherNet website does so by county at Look for summary reports, then Growing Degree Days, then Chelan County. For 2019, the accumulated GGDs at the WSU Tree Fruit Research Center as of the date of this writing using 50 degrees as the base temperature are 0. By the time this article is published, it will be significantly more. Using a base temperature of 32, however, the GGDs during the same time period are 119.
So, how can we use the number of GGDs to predict the appearance of insect pests? At this early spring time of year, with GDDs ranging between 1 and 49, it’s time to be checking your plants for insects such as mites, adelgids, aphids, and mealybugs. Inspect leaves for the presence of overwintering stages and last season’s damage and treat with dormant oil as needed. In mid to late spring, when GGDs range from 300-399, the elm leaf beetle larvae will begin to appear. Look for 1/4 inch green or yellow larvae with black stripes and spots. If you see evidence of their presence, check Hortsense for treatment options.
As the winter snow gives way to the warmer temperatures of spring, now is the time to be on insect watch in our gardens. Growing Degree Days are a useful tool to use as a guide, but are not a substitute for being watchful.
By Casey Leigh

Leafhoppers and the Beet Curly Top Virus — 8/1/2019

A few of the plant samples brought into the clinic this week had been attacked by viruses. One that was identified on a tomato leaf was the beet curly top virus. Transmitted by the beet leafhopper, it can infect many of our garden vegetable plants, such as tomatoes, beets, cucumbers, peppers, beans, and squash.

If your plants’ leaves pucker with an upward rolling and twisting, followed by yellowing, you could be dealing with beet curly top. In addition to turning yellow, mature plants have stunted growth, the leaves thicken to either a brittle or leathery texture, and the veins can turn purple. Young plants are more likely to die from the virus than older ones.

Hortsense does not recommend any chemical treatments. Instead, it suggests destroying any infected plants. Shading plants when young can reduce the chances of a viral infection as leafhoppers don’t usually feed on shaded plants. Spinach and beets are hosts for the leafhopper and the virus. Unfortunately, control of leafhoppers is not an effective method for preventing an infection.

I recently read an article on cutting edge research of plant viruses being done at WSU. According to a June 2019 article in WSU’s Insider by Scott Weybright of the College of Agricultural, Human, and Natural Resource Sciences, recent research by a WSU team of scientists led by Dr. Hanu Pappu suggests that artificial intelligence (AI) has the potential to predict which plant proteins a virus will attack.

According to the article, “Viruses attack a small number of proteins in plants, but those attacks are enough to hijack an entire organ-ism. Predicting which protein a virus will attempt to hijack can help in building a defense against the attack. But plants make thousands of proteins, making this kind of prediction very difficult.”

With cotton plants for their experiment, the scientists were able to use AI to narrow the protein targets of the virus that causes cotton leaf curl disease from thousands to two likely ones. They then discovered that one of the critical plant proteins was the one that the virus attacks. By finding the proteins that viruses target within a plant, Dr. Pappu posits it may be possible to intervene and design defenses that would help plants resist viral attacks.

Perhaps in the future, thanks to the work of researchers such as Dr. Pappu, the beet curly top virus and others will no longer be a threat to the favorite vegetables we grow in our gardens.
by Casey Leigh

Meal Moth Control – 4/1/2017

Trivia question: What moth is the only species of the Plodia genus found in the US?
Answer: the pesky Indian meal moth, Plodia interpunctella. This half inch moth and its larvae are most often found in your pantry or kitchen – anywhere where plant based food products such as flour, oatmeal, nuts, bird seed, and chocolate are found. The moth was given its common name by a 19th century NY State entomologist after discovering the larvae in cornmeal, which at the time was known as “Indian meal”. We MGs in the plant clinic were called upon to identify this moth earlier this month.
The adult moth has a bicolored forewing – light gray and reddish-brown. It’s actually very pretty. The moth itself doesn’t do the damage, but does more than its fair share of harm by producing several generations of the larvae that can wreak havoc with your food stores each year. The larvae have a white/yellowish body and a head from yellow to reddish-brown. The larval stage of five instars can last from two weeks to 300 days, the time depending on temperature. At about ¾” long, the larvae work their way through the food, creating a silken web – the evidence of their presence. You may also see frass and pupal cases mixed in.
What do you do if you discover you have a meal moth problem? WSU does not recommend using chemicals to solve the problem. Rather, once you find evidence of their presence, throw out all food sources that are not in tightly sealed containers. Because the larva can eat through plastic bags and thin cardboard, they could be in unopened boxes of food. All stages of the moth are temperature sensitive so can be killed by freezing for a week or heating in the microwave or oven for a short period of time. After ridding the area of the infested and potentially infested food, scrub the area with a mixture of soap and water or vinegar. You can also set up pheromone traps to capture the adult moths.
*The information for this article came from;; and
By Casey Leigh

Pine Wilt Disease – 9/1/2021

One of the joys of being part of the plant clinic team is learning something new almost every time we meet. Our clients bring in some very interesting questions. For example, last week a client emailed a photo of a pine tree that was dead and asked what had happened. After discussion, the clinic team needed more information. We emailed the client asked for more information and photos, but one possibility we discussed is Pine Wilt Disease.
Pine wilt disease is a complex disease that is of concern not only to homeowners but to forest managers as well. It is a devastating disease that can kill a tree in as little as three weeks. One of the factors in the development of this disease is high summer temperatures. (We have certainly had that this summer!) In the past, pine wilt disease has not been a big problem in the Northwest. However, with climate change bringing high heat and ever hotter summers, it is feared that pine wilt disease will become a threat to our pine forests.
Pine wilt is caused by the pine wilt nematode (Bursaphelenchus xylophilus) or PWN, a microscopic roundworm. PWN causes rapid wilting and mortality in susceptible host trees, especially pines. The pine needles fade to gray-green or brown and wilt. The needles remain attached to the tree. Often just a branch appears to wilt, but eventually the whole tree wilts and dies.
The life cycle of PWN is complex and involves interactions between the microscopic nematode, its vector beetle, and the host pine. The PWN’s life cycle is short, developing from egg to adult in three to five days. In the early stages of pine wilt, pinewood nematodes feed on plant cells surrounding resin canals or water conducting (xylem) cells in pine trees. As nematode populations increase, they move throughout the tree and interfere with the flow of water and nutrients ultimately causing death of the tree.
Pine sawyer beetle is the vector beetle. Females chew a small hole in the bark of recently dead, dying, or declining pine trees and lay their eggs. Young larvae feed on the inner bark, cambium, and outer sapwood. Older larvae bore into the heartwood and then tunnel back toward the surface creating characteristic U-shaped tunnels. At the last stage of larval development, they form a pupal cell at the outer end of the tunnel near the surface of the wood. After pupation, the adult emerges by chewing a hole through the remaining wood and bark. As adult sawyer beetles emerge from the wood colonized by pinewood nematodes, the nematodes have already moved into the beetles’ respiratory openings and are carried in the tracheal system. Beetles become vectors for the nematodes as they visit healthy trees to feed on bark and introduce the nematodes to the tree through the feeding wounds.
There is no cure for pine wilt disease. The diseased tree must be removed as soon as possible and destroyed by burning, burying, or chipping. Stumps should be removed or ground and buried at least six inches deep. If pine sawyer beetles are thwarted, the PWN will not have a chance to enter trees.
(Much of this information came from the Cooperative Extension Services of Oklahoma State University and Colorado State University and can be found online.)
By Pat Beeman

Rose Galls – 1/1/2020

During the 2018 fall clean-up at the CEG we came across some interesting growths on the Rosa glauca in the Welcome Garden. Upon further inspection, these mossy looking balls on the branches were identified as galls. An easy solution to combat insect induced galls is to simply prune them off, and this is what we did. I placed the galls in a container with a fine mesh lid and tucked it away in an outdoor area protected from sun and moisture. I then promptly forgot all about them until this fall and decided it was time to investigate.
These particular galls were produced by the tiny wasp Diplolepis rosae. This wasp has several common names such as Bedeguar Wasp and Mossy Gall Wasp. Females lay eggs within unopened leaf axillary or terminal buds of several wild rose species in the spring or early summer. The ensuing larva begin to feed on the tissue, chemically inducing its distortion. The mossy galls contain several individual cells, each containing a single larva that feeds, grows, and molts. The larva overwinters in a pre-pupal stage and transforms into a pupa the following February or March. The Mossy Gall Wasp is parthenogenetic, meaning all these offspring will be female clones of their mother. These females will emerge from the previous year’s gall in May through August and begin this process once again.
The full story of the Mossy Gall Wasp is layered with a complex ecology of parasitoids, hyperparasitoids (parasitoids of parasitoids), and inquiline gall wasps (wasps that lay their eggs in the galls induced by D. rosae). Additionally, an endosymbiotic bacteria is likely the culprit behind D. rosae’s lack of (only 1-4%) male progeny. So what did I find in our very own Mossy Galls?
Dozens of Diplolepis rosae wasps littered the bottom of the container. As I sifted through them under the microscope, a couple small wasp figures caught my eye. They were the parasitic Ichneumonid wasp Orthopelma mediator. This means the eggs of this wasp were laid directly into the developing D. rosae larva and then they consumed their host. Specimens of the rose galls, D. rosae, and the parasitoid O. mediator have all been curated into the Plant Clinic collection.
Feel free to take a look the next time you stop by!
By Tawnee Melton

Sequoia Pitch Moth – 5/1/2019

Our article this month discusses an insect whose larvae found on the Hortsmann’s Silberlocke Korean Fir in the Welcome Garden of the CEG: the sequoia pitch moth. In this month’s “Lessons Learned” column you will learn about this discovery, the damage it caused, and options for dealing with the problem and the damage.
This article describes the life cycle of the sequoia pitch moth, trees that are susceptible, the signs and symptoms that alert you to the presence of the insect, and WSU recommended options for prevention and control.
The Sequoia Pitch Moth, Synthanthedon sequoiae, is in the Lepidoptera order. The adult moth is very similar in appearance to a yellow jacket wasp but with clear wings outlined in black. As with most insect pests the larva causes the damage. The larva is about an inch in length with a yellowish body and reddish- brown head. The adult moth, which is seldom seen, lays eggs from late June through July. Eggs are laid in bark crevices, junctions of limbs and boles, and in wounds caused by pruning or another abiotic cause. Larvae bore under the bark and enter the phloem and outer layers of the wood causing pitch masses to form at the site of entry. The pitch is creamy yellow to pink in color but hardens and looks whiter as it ages. The larva pupates for 2 years before emerging as an adult. Prior to emerging the pupa will push most of the way through the pitch, allowing the adult form to avoid the sticky pitch.
In addition to the Hortsman Korean fir, host plants include many pines such as ponderosa and mugo. Douglas fir and spruce are less commonly affected and sequoias are rarely a host. Trees planted on dry sunny slopes are more at risk. Damage is initially cosmetic and localized. However, the pitch can girdle a limb which can kill the branch. Entire trees can be girdled but this usually occurs only in smaller trees. Infestations can be confirmed by finding a larva or pupa within the pitch mass or the pupal skin in the pitch. Infested trees are usually stressed.
Prevention is the key to management. Avoid over- or underwatering plants. Timing of pruning is essential in this regard. Adult moths will be attracted to wounds in the tree caused by pruning. Since they are active June-July, pruning should not be done during this time.
Recommended time for pruning to avoid infestation is October-February.
Control is mainly through removal of the pitch mass. Be sure to dispose of them as they may contain the pupa. Removal will prevent girdling as well as keep the adult moth from being attracted back to the tree. Pheromone sticky traps can help with heavier infestations. WSU does not recommend any home chemical control.
In summary, this pest can be controlled by good IPM techniques including proper initial tree placement, watering and monitoring for signs of stress such as broken limbs and pitch masses.
For further information, here are the resources used for this article:
Pine (Pinus)-Sequoia pitch moth | Pacific Northwest Pest Management Handbooks (;;
By Casey Leigh

Sequoia Pitch Moth – 5/1/2022

Every so often a visitor to the plant clinic brings us a pine branch with a gummy substance adhered to it. What is attacking my pine tree? Fungus? Insect? The pitch mass does look pretty intimidating.
The culprit is a sequoia pitch moth (Synanthedon sequoia). The Sequoia pitch moth infests pines and select other conifers. The adult moth is clear winged with yellow and black markings resembling a yellow jacket wasp. The larvae that do the damage are about one inch long, yellow in color with a red-brown head.
The moth lays eggs beneath the bark or in branch or bark wounds. The larvae feed under the bark of the trunk or a branch. A large pinkish mass develops at the point of entry. As the pitch masses, the pink tinge disappears and it takes on a hard grey appearance.
The host plants are pines such as Austrian, ponderosa, mugho and shore pine. The moth can also attack Douglas fir and spruce. Feeding is local and damage is usually aesthetic. However, extensive damage to small trees can cause girdling and death of the tree.
Because WSU does not recommend chemical control, maintaining the overall health of the tree is key. Avoid stress from over- and under watering. Don’t prune from March to October as pitch from the wounds attracts the moth. When you see the pitch masses, where possible, remove them and dispose in the garbage as larvae in the pupal stage may be present within the mass.
(This article is based on information compiled by Orv Vanderlin in July 2008.).
By Linda Sarratt.

Six ‘Bad’ Insects and What to do About Them – 5/1/2016

An unseasonably warm spring has all of us out in our gardens early this year. As our thoughts turn to the beautiful blooms our flowers will produce and the bounty from our vegetable and herb gardens, they can’t help to turn also to the age-old question: How will we keep the “bad” insects from destroying all our hard work? And on the positive side, what can we do to encourage the presence of “beneficial” insects? It’s the classic “good bug/bad bug” dilemma. This month we will focus on the “bad bugs.” Next month we will look at the beneficials.
For this article, Keith and I have chosen 6 insects that we get the most inquiries about in the clinic: aphids, stink bugs, squash bugs, root weevils, scale, and spider mites. Let’s start with the aphids, those tiny, soft-bodied in-sects whose piercing, sucking mouths seek out the sap from your plants. Signs that you have an aphid problem are curling, distortion, and discoloring of stem tips and new leaves. You may also notice their “honeydew” excretions that accumulate on surfaces of the plant and attract ants who feed on it. Fortunately, many of our beneficial insects find aphids to be a tasty meal, including lacewings, ladybugs, parasitic wasps, and damsels bugs, among others. You can also flush them off your plants with a strong stream of water from a hose. For those of you who aren’t squeamish, you can hand pick them off if you don’t have a large infestation. Finally, pay attention to your use of fertilizers as high levels of nitrogen enhance aphid reproduction.
Next, the stink bugs, particularly the brown marmorated stink bug (BMSB) which, unfortunately, has made its way to our region. Like the aphids, they are sucking insects. Although they prefer fruit, seeds, and seed pods, BMSBs feed on stems and leaves of some plants. They make their presence known by causing deformities in the fruit, such as dimpling, pithiness, and discoloration. They have the classic stink bug triangular shape with brown and white checks around the wing covers. Adults overwinter in sheltered locations, including our houses! Therefore, keeping cracks in your house sealed is one way of disrupting their life cycle. You can also buy traps to catch them. Once you spot them in your garden, you can pick and destroy eggs, groups of nymphs, and the adults; this will be effective if your infestation is not too bad. You can also shake the plants over a drop cloth and flush them down your toilet.
One of the most common insects brought into the clinic for identification is the squash bug. This 5/8” long dark brown bug also belongs to the piercing/sucking group of insects. Adults lay brown to reddish eggs along the veins of new leaves. Both nymphs and adults like to feed on new leaves, leaving small yellow specks which cause the leaves to turn brown and die. Adults also attack the vines by injecting a toxin that turns the vines black and crispy. A good way to keep down your squash bug population is garden “house cleaning” in the fall as they overwinter in garden debris, as well as sheltered places. In addition, hand pick and destroy the adults, nymphs, and eggs. Check WSU’s Hortsense website for chemical management alternatives.
Root weevils are serious pests for landscape plants such as azaleas, rhododendrons, roses, and strawberries. Signs of weevil damage are notchings along the leaf margins. The larvae feed on roots and can girdle crowns and lower stems. Beneficial nematodes can be applied to kill the larvae once soil temperatures reach 53 degrees. In addition, consider planting root weevil resistant varieties when available.
Scale, which comes in many species, is another piercing/sucking insect that looks like raised bumps on many parts of your plants. They cause leaves to yellow and plants to be stunted. If the infestation is severe enough, they can weaken stems and branches. Like aphids, they produce a honeydew. Since their honeydew attracts wasps, yellow jackets and ants, presence of these insects around the plants can be indicative of a serious infestation. Lace-wings, ladybugs and parasitic wasps will attack the scale. You can clean scale off the plants using a cotton ball soaked in rubbing alcohol or hand squashing them. Once again, avoid over fertilizing as it assists in scale reproduction.
Lastly, the spider mite can become a serious problem for our ornamentals. Spider mites are not insects, but 8-legged arthropods with piercing mouth parts. They are less noticeable than other pests in that they are usually found on the underside of leaves where they create strands or mats of webbing. Damage shows up as yellow or bronze-colored stippling of leaves; dropped leaves indicate severe spider mite damage. Spider mites thrive in hot, dry conditions and high levels of nitrogen in the foliage. Like aphids, mites can be hosed off plants with a steady, strong stream of water. Predatory mites, ladybugs, and green lacewings are natural predators.
For more detailed information on these and other garden pests, WSU hosts two excellent websites: Hortsense and Pestsense. A handy reference I consult often is Good Bug, Bad Bug: Who’s Who, What They Do, and How to Manage Them Organically by Jessica Walliser.
By Casey Leigh.

Slugs – 3/1/2019

Have you ever said to yourself, “I feel like such a slug today.”? A slug, or sluggard, is defined at as “a person who is habitually inactive or lazy.” Although those adjectives may apply to a person, your garden slug is far from inactive or lazy once March rolls around. In fact, they are awake and active, searching for their first meal of the season.
Slugs belong to the class Gastropoda in the phylum Mollusca. The word “gastropod” is a combination of two Greek words meaning “stomach” and “foot”, earning the slug its reputation as a stomach moving on its foot along self-produced mucus, creating its diagnostic slime trail. Slugs, which feed on a wide variety of vegetables and herbs, as well as some of our favorite annuals and perennials, can eat several times their weight in food per day! Sexually, slugs are hermaphrodites, with both male and female reproductive organs. Mating occurs in fall and spring. A prolific species, one female can lay up to 500 small (1/4”) transparent, white, or golden colored eggs a year in clutches of 3-50.
The gray garden slug, the most prevalent in our area, can live up to 18 months. Consisting mostly of water, slugs search out moist environments. You can find them hidden under boards, stones, leaf litter, and in mulch and weedy areas, often underground. To catch them feeding, your best bet is to go out after dark as they shun sunlight, their worst enemy.
Slugs, although a scourge to most gardeners, play a beneficial role in the environment. They contribute to healthy soil by recycling organic matter. They are a tasty treat for many animals, including frogs, garter snakes, and many of our local birds. Keep this in mind as you realize the impossibility of eradicating slugs from your landscape.
But slugs can be controlled, and early spring is the time to begin your control efforts. Hortsense recommends several strategies. If you have the stomach for it, hand pick and kill slugs, either randomly as you see them or as part of a night-time slug hunt. Use natural baits such as small cans buried in the ground and filled with stale beer. Culturally, keep your garden clean by removing their favorite hiding places whenever possible. Don’t allow tall weeds and grasses to grow up around your garden.
Hortsense lists pesticides legal in Washington that kill slugs. However, they urge using caution as pets can be poisoned. They suggest using iron phosphate baits which are safer to pets. Other options include adding plantings that slugs avoid and placing barriers such as copper strips and diatomaceous earth around your favorite plants.
If you start early to get on top of slug control, you will save time and frustration later in the season when you plan on enjoying the fruits of your gardening labor.
By Casey Leigh.

Varied Carpet Beetle – 3/1/2017

Clients at the Plant Clinic during the cold winter months are few and far between, leaving us time to catch up on research and special projects. But we have had a recurring question: What is this bug I found in my house? Answer: Varied Carpet Beetle (Anthrenus verbasci).
This common tiny insect, 1.7-3.5 mm, looks nondescript to the naked eye, but its beauty is revealed under a microscope or hand lens. Its yellowish brown, black, and white dorsal surface reminds one of the calico coat of a cat. Known as wooly bears, their mature larvae are colorful as well, with light and dark brown stripes along a hairy body. The female carpet beetle lays approximately 40 eggs in the spring to early summer. Favored spots are bird nests and fabrics stored inside your house. In approximately ten to eleven months, the larvae emerge as adults. During that time they go through up to 16 larval stages and one dormancy period. Adults can live up to 44 days, but two weeks is the normal lifespan.
The second questions is: Are they a problem? Answer: Adults, no; larvae, can be. Adults feed on flowering plants. Their larvae, however, feed on organic matter, including all types of textiles, furniture, carpets, food, and even insect collections. Signs you have larvae are the presence of brown, shell-like, hairy skin molts. To reduce the chance of infestation in your home, vacuum regularly; keep fabrics and furniture cleaned; air clothes in your closet or stored in boxes (as larvae like dark, secluded sites); check cut flowers you bring into your house for adult beetles; don’t store foods in your pantry for long periods of time unless they are in a tightly sealed container; and remove abandoned bird and wasps nests from near your house.
In most instances, chemical control isn’t needed. Thoroughly clean the area or article where there is evidence of the larvae and, if necessary, dispose of the infested food, clothing, etc. Remove adult beetles when you see them in your house. Doing these things should prevent the expense of calling in a pest control company.
*Information for this article was taken from,, and (“Garden Insect is a Household Pest” by Marianne C. Ophardt).
By Casey Leigh.


Propagation and Other Fun Things to Try

Planting Dahlia Tubers – Where, When, and How?

Dahlia plants grow from tubers. Some dahlias are grown from seed and new varieties are usually developed from seed. Seed from named dahlias will not produce the same blooms as the parent but will be a mixture of the color and characteristics of the parents of that plant. Therefore, it is necessary to plant a tuber or a cutting of a particular cultivar in order to have flowers of that form and color.

Buy dahlia tubers from a reputable dahlia growers or local dahlia society sale. The quality off the tuber makes a difference. A good source to find a supplier of a certain tuber cultivar you’re looking for is Buy tubers with visible eyes located at the top of the tuber, called the crown. Unlike potatoes which have eyes all over, dahlia tuber eyes are only found near the end where the tuber attaches to the plant stem. The tuber should have an eye showing. The eyes can be difficult to spot so ask the seller, dahlia friend, or an expert to locate the eye for you. Buy plump, healthy looking tubers with no sign of decay.

It goes without saying that conditions for growing dahlias vary, depending on climate in the growing location. Dahlia growers are dedicated to successfully growing dahlias all over the world, in spite of the natural conditions in any area. In Eastern Washington there are four distinct seasons. Casual growers who use dahlias as part of their landscaping or grow for cut flowers will find that dahlias are fairly hardy, as long as they receive proper watering and sunshine.
First, we’ll talk about the garden plot. The ground should be weed free, warm, and well drained at planting. Heavier soil needs to be amended with organic matter such as aged composted manure, alfalfa meal, or purchased compost to lighten and loosen the soil texture for better drainage. These additives should be incorporated into the soil before planting.

When to Plant: In the NCW area or similar climate area plant tubers once all danger of frost has passed. Normally, this has been mid-April to early May. Soil temperatures should be at about 60 degrees or warmer at 4 to 6 inches in depth, which is the planting depth. An inexpensive soil thermometer to check the soil temperature can be purchased at the local hardware store. For best results, dahlias need a sunny location to thrive. Plant in lightly moist soil in an area that receives 6-8 hours of direct sunlight is best.

Dahlias that reach 3 feet tall need to be staked. Set the stake before the tuber is planted to avoid the possibility of damaging the tuber or the root system. Stakes need to be 4 – 6 feet tall depending on the height of the dahlia cultivar. Plant the dahlia tubers about 18 – 24 inches apart. Stakes will support the weight of the full-size plant and help support the plant during windy weather. Any staking product will work; metal t-posts, rebar, wooden garden stakes, or bamboo stakes.

Watering in the dry Eastern Washington climate can be tricky. Only minimal water is needed until you see the dahlias sprout through the soil. Tubers are prone to rot from too much moisture, but they do need some moisture in the soil. Young dahlia plants do not need a lot of water. When reading material on how to grow and maintain the dahlia bloom make sure the writer is giving instructions about a similar zone/climate in which you grow.

The American Dahlia Society has helpful information about growing dahlias. Visit this site at:
There are several well-versed dahlia growers within WSU Chelan/Doulgas Master Gardeners. Contact our Plant Clinic or ask Marco to put you in contact with someone that can give month to month guidance to growing the dahlia.

By Mona Kaiser.

Growing Native Plants From Seed – 10/1/2022

Climate change is bringing many challenges to gardeners: increased heat; potential scarcity as well as increased cost of water; and reduced pollinator populations due to habitat loss. Using native plants lessens the impact of these environmental challenges. Native plants add biodiversity to the garden; they are tolerant of dryness and heat, and they support our pollinators. If you have an interest in adding native plants to your garden, one possibility is to use seeds. By seeding natives, especially wildflowers, one can expand the number of plants at a low cost. You can find seeds for native wildflowers that are unavailable as plants from local growers. Plus, you will learn a lot about seeds, soils, and micro-climates in the process.
I’m no expert, but I can share some of what I have learned by experimenting over the last few seasons. From books and online sources one can find photos and habitat information and be introduced to plants you may not know. I found the University of Washington’s Burke Museum app called Washington Wildflowers especially useful. Knowing the true genus and species of our local natives helped as I looked for seeds. Choosing flowers that I want to grow, evaluating different sites in my yard and addressing soil, sun/shade and water needs are more varied and detailed for natives than for most horticultural offerings. Having a soil test done is a good start. There may be some site preparation needed. Although many natives in our area are adapted to low fertility soils, you may need to add organic matter to your soil. I find adding compost to the planting area is useful when transplanting seedlings or growing “meadow” or riparian area plants. If the plant likes a sandy dry site and good drainage is important, I have added gravel and sand to my sandy loam yard soil in those areas.
Seed growers will give seed preparation and germination information, sometimes very detailed. Often this means stratification and /or scarification of the seed and the depth of planting. If the seed company says to direct seed, this may indicate it germinates readily and/or that the plant’s early days are directed at growing deep tap roots, making transplanting more difficult. In these cases I have had success planting in a 9”W x 24”L x 9“ D container. I could keep track of my seedlings and prevent squirrels from digging them up – I had to use a trenching shovel to get them out of the planter, but it worked out. I haven’t had much success with direct seeding if cold stratification is needed, so I am turning to Outdoor Propagation, sowing seeds in pots, tubes or flats. Mel Asher from Derby Canyon Natives uses a combination of peat moss and vermiculite, planting in tubes. (Use a few seeds per container even 2-3 seeds in the tubes. Natives seem to benefit in early stages by growing in clumps. Thin them later.) Fill the chosen container, moisten medium, plant seed at correct depth, then cover the seed with sand or grit at the same depth as the width of the seed. Even seeds needing light to germinate will benefit from a light dressing of sand. Sand keeps the soil and seed from dislodging in the rain. Sand also helps support young seedlings. Place your seedling container outside in appropriate sun/shade locations. For stratification, plant seeds November to January. Annuals not needing stratification can be started in pots or flats or direct seeded in February/March. If direct seeding a plant that needs seed stratification, you can put the seeds in a stocking and place the stocking surrounded with moist peatmoss in a container and keep it outside with your other pots. This allows you to keep track of just the seed. Add sand to seeds before direct seeding as many are very small to aid distribution . Once seeds germinate in the spring, water as appropriate, adjust the location of your containers as light and temperature change. Some plants will be ready in a few months; for perennials this process may take up to 2 -2.5 years before they are of a size to plant Into the garden. For more detailed information please see references below. Happy Gardening!
SEED SOURCES: Washington Native Plant Society, Native Plant and Seed Sources 2022, Alplains Seed Company, Thorn Creek Native Seed Farm
INORMATION: University of New Hampshire, Planting for Pollinators, Establishing a Wildflower Meadow,, University of Maine, Planting Plants from Wild Seed,, and referral to
By Dee Curcio

How to Grow Lupines from Seed – 11/1/2022

Lupines (pronounced loo-pins) are one of the most beautiful spring wildflowers in the Wenatchee Valley and foot-hills. We are blessed with a variety of species of native lupines, including Bigleaf (Lupinus polyphyllus), Broad-leaf (Lupinus latifolius), Silky (Lupinus sericeus), and Sulphur (Lupinus sulphureus) ( Lupines are in the Pea family (Fabaceae); have deeply lobed palmate leaves with five to nine leaflets; grow 1 to 4 feet tall; bloom in the spring; and have conical, spike-like blossoms of many 5-petal, uniquely-shaped flowers characteristic of the pea family. Most of the lupines in our area are purple or bluish purple; even the Sulphur Lupine, which is typically yellow in most of Washington, is purple here ( Sulphur lupine | Chelan-Douglas Land Trust ( Lupines are biennial or short-lived perennials. Lupines benefit our native lands by having deep tap roots for stabilizing soil and the ability to fix nitrogen which increases native soil fertility.
Most home gardens do not contain native lupines but may contain commercial, often hybridized lupines that are much easier to obtain than the natives. Native lupine seeds and seedlings are available at many nurseries and seed suppliers in Washington State ( Once established, native and commercial lupines cannot be transplanted because of the long taproot. Seeds, however, can be easily harvested after the spring bloom. Break the seed pods off after the flowers have dried out and the seed pods look yellow/brown. Be careful as the seed pods often will break open and disperse the seeds. Place the seeds/seed pods in a paper bag and wait until fall (or spring) to plant them. Seeds from hybridized lupines are rarely collected because the plants grown from them typically do not look like the parent, hybridized lupine. Note that it is illegal to collect seeds from public lands. I’m fortunate in that I have several friends that have offered to let me collect seeds from lupines on their properties in Wenatchee Valley and the foothills.
Most gardeners, especially those planting native lupines in their shrub-steppe backyards, will prefer to directly plant the seeds in late fall or early winter. Lupines seeds require scarification and stratification to germinate. Scarification is the process of breaking the seed coat to allow water to enter the seed. Scarification is accomplished in nature by freezing and thawing during the winter. Scarification may also be done by gently rolling the seeds over sandpaper or a file until the seed coat begins to change color. This should be done right before planting as the sandpaper process can leave seeds vulnerable to infection and decay. Stratification is a cold, wet period that breaks seed dormancy. This occurs during winter in nature. For those gardeners that want to plant seeds in spring, the seeds will need to be placed in the refrigerator in a ziplock bag with a moist paper towel 1 week before scarification and planting. Sow seeds ¼ inch deep and 1 foot apart in loose, well-drained soil with lots of sun. If you can, loosen the soil about 1-1.5 feet deep to allow for optimal taproot growth. Lupines don’t tolerate clay soil and prefer slightly alkaline, sandy, poor-fertility soil. Keep the seeds evenly moist during the spring to encourage germination but don’t overwater once they are established. Seedlings should emerge 15-25 days after planting in the spring. Lupines can be planted in containers, but the long taproot requires a deep container. Once established, lupines require little care. Lupines are deer- and rabbit-resistant and attract pollinators such as bees, butterflies, and hummingbirds.
Enjoy your lupines!
Elysian Fields: Growing Lupine From Seed, James Everly
Complete Guide to Plant, Grow and Care for Lupine Flowers, Eric Vinje July 13, 2022

Complete Guide to Plant, Grow and Care for Lupine Flowers

By Jeff Martin

How to Overwinter Geraniums – 10/1/2013

Geraniums—at least what we commonly call geraniums, are the workhorses of the summer garden. In full sun they bloom all season. We often find a special one that we wish we could over-winter. Pellegoniums originated in South Africa where they actually grow as small shrubs. Sadly, the first nights of 40 degrees will kill our summer lovelies. So, can geraniums be overwintered?
Here are your choices:
• You can kiss the plants goodbye. Let them die back and compost them.
The advantage of this option is new is better and who knows what is waiting at the garden center next spring. Starting with new plants ensures that they will take off in your landscape ready to make any sunny spot colorful.
• You can bring them into the house and attempt to make them into houseplants.
This is the most problematic option. The plants will need to be transplanted into huge pots, which are bulky and heavy. Most outside plants resent being brought inside, and they will pout. The plants will lose their leaves; they will quit blooming, and the leaves will get smaller and smaller because you cannot provide as much light as the geraniums were accustomed to outside. Even worse, the plants become a magnet for bug infestations. You name it, geraniums attract it: aphids, spider-mites, scale, and white fly. These infestations will travel to your other houseplants. Who knows, the plant’s soil may be harboring some exotic pest such as spiders or earwigs or slug eggs.
• You can bring them into a sheltered space and over-winter them.
Geraniums have been in our gardens since the 1720’s, and they can be surprisingly long lived. My geriatric geranium, is now 32 years old. It goes outside in a pot in the summer, and winters over inside. There are as many over-wintering techniques as there are grandmothers who did this for years. Some of the techniques are more trouble free and more successful than others.
You take the plant out of the pot and leave on as much soil as possible. Some people hang the plants upside down in the garage. I found no actual reasons for why the plant has to be upside down. Some people put them in brown paper bags. Essentially, the plant is forced into a drought dormancy. You can check on it every once in a while. It needs no light, it but needs a sprinkle of water every once in a while. Store it in a place that is about 45 degrees. This technique is not as successful in NCW as it is in other parts of the country that have higher winter humidity. We are both dry and cold during the winter. Try this technique with plants you have not fallen in love with.
Cut the plant back by three-fourths and put it in a 45 degree room with some light. Water only if the plant is really dry. This plant will put out some new growth—be sure to check for insect pests because they can easily kill the plant in a short amount of time.
In the fall, take cuttings about 12 inches long and remove most of the leaves and all the flower buds. Put the stems in an opaque container filled with water. Check the water level every once in a while and be sure none of the leaves are rotting in the water. The stems will root. When they have rooted in late February, move the stems into moist potting soil. Put the plant in moderate light so that it can sustain itself until you are ready to plant it out-of-doors.
A serious warning to avoid heartache. After you have spent the winter worrying and mussing about your geraniums, they must be hardened off before they are planted outside. Beginning in mid-April, (this is really labor intensive) move the plants daily outside for longer and longer periods and into more and more intensive light. They must be brought in every night. Generally, the plants are not ready to transplant out into the garden until Mother’s Day because the soil is not yet warm enough. You can tell if it is not warm enough because the leaves develop red leaf margins.
So— maybe option one is a great choice. I personally do option three using water sprouts and resting, heavily pruned plants.
By Bonnie Orr

Propagating Plants Takes Patience, Attention to Detail – 4/1/2023

“Sometimes we get in a rush to hurry-up spring. But you cannot speed up Mother Nature. My friend, neighbor and fellow master gardener, Craig Lawrence, tasted some of my Interlaken grapes and drank some of the juice I made from the Glenora grape, and decided what he needed was a grape vine to create a visual border near his back fence. It was tempting last month when he made the request to take some vine clippings and get growing. But it is all about timing. Fellow master gardeners have expressed their disappointment at the failure of their cuttings to root and thrive. When I have asked when they attempted to start the new plants, I received such answers as “in September” or “in January.” (We all want to garden year-around, don’t we?) To successfully start plants from cuttings, the parent plant must be in a vigorous growth period. For example, I never start new rose plants until the middle of June. If the plant is dormant, it just does not have the “umph” to put out new growth or to root even when hormone is placed on the end of the cutting.
Another error made by eager gardeners is misapplying growth hormone. You know the adage, “a little is good; more is better.” When hormone powder or liquid is spread on both the cuttings stem and base, the plant becomes confused. (That is not a scientific explanation, I know). You want roots to grow from the bottom of the cutting, so that is the only place you apply hormone.
Desiccation is another problem with cuttings. This is dealt with in two ways. The single leaf on the cutting is going to photosynthesize for the new plant. If the leaf is large, cut-ting it in half or even fourths will still provide enough photosynthesis, but the leaf will not dry out because there are yet no roots to draw up water to the leaf.
Besides downsizing the leaf, the other way to prevent desiccation is to use a cloche. A cloche can be anything that prevents water from evaporating from the soil and from the stem and leaf. My favorites are the wine glasses that the dishwasher broke the stems from. A mason jar, a clear plastic cup, a lidded salad box, etc., also work. Plastic wrap is not really a satisfactory choice because it is too thin.
The “soil” should be fine-textured seed-starting mix. This “soil” will hug against the sides of the cut-ting and prevent desiccation. Water with 80 degree water so the cutting thinks it is nearly summer. So as soon as the grape leaf buds unfurl, I will take the cuttings to start the new grape vines.
By Bonnie Orr

Seed Planting – 2/1/2017

Starting your own plants from seed is exciting. It can also save you time and money in the long run. More varietal options are available and the cost of seed verses plants is much less. Some seeds are more difficult to start than others. If you are new to this, start by investing in your equipment and begin with easier plants such as tomato, lettuce or marigold seed. Many long season vegetables like brussels sprouts should be started indoors in order to produce sufficiently. Some annual flowers need a head start indoors if they are to bloom during the season. Be sure to read your seed packet for specific directions.
There are lots of choices for containers. Providing heat is not a necessity but I explain why I think you should. You will need the following –
Heat (optional)
Containers – These can be store bought, made yourself or you can use recycled containers. Store bought seed trays contain individual cells for each seed. Onions and leeks transplant easily and can be started in large flats. You can find pots made from organic material such as peat or shredded ingredients. People use strips of newspaper to make pots. Both are nice for transplanting seedlings whose roots do not like to be disturbed. All reused trays and pots must be sterilized. Remember – all containers must have drainage holes.
Soil – Do not use garden soil which carries weed seeds and pathogens. Begin with a “seed starting” mixture. Fill your containers and water well. Soil will settle, so fill some more and water again. Make labels for each tray, pot, or flat. I don’t need a whole tray of peppers so I have several labels per tray. It is no fun to have what you thought was a cherry tomato plant grow into a massive indeterminate beefsteak! Do not add fertilizer. Seeds have all the nutrients they need to begin their life.
Seeds – Don’t be overly swayed by beautiful pictures on seed packets. Buy only what you need and keep your plans realistic. If you are a new gardener, I suggest you start with new seeds. Older seed have a lower germination rate. Look critically at the available space you have. Can you devote space for 4 months to gar-den plants? A 72 cell seed tray could conceivably produce 65 seedlings which need transplanting into 3-4 inch pots. Will you have the space?
Heat – Vegetables, like tomato and pepper, need warm soil to optimize germination: 80-85 degrees. Plants of the Brassica genus, such as kale, like it cooler: 70-75 degrees. The top of older refrigerators are warm enough. However, to speed up germination and reduce surface pathogens, many gardeners use a heat mat.
Light – Most seeds do not need light to germinate. Once most of the seeds in your tray start to sprout, place them under lights. Plants placed on windowsills do not receive enough light and that light is weaker. This type of light produces weak stems (“leggy”), which are not healthy plants. The most inexpensive lights are T12 florescence shop lights. More energy efficient bulbs are T5 and T8. The “T” stands for tube and the number is the diameter of the tube. Unless you are growing to produce flowers or fruit, you do not need to be concerned with different light frequencies. Make sure you can either lower your lights or are able to raise the containers to keep the seedlings close to the light source. Seedlings need to stay 2 to 4 inches from the light source.
By Emilie Fogle


Trees and Shrubs

April: A Good Time to Take a Close Look at Your Trees – 4/1/2018

The approach of Arbor Day and trees and shrubs appearing in Sav Mart’s parking lot outdoor garden center remind us in clinic that soon we will be fielding questions about planting trees. So this month we will share tips on planning where to plant trees that will thrive and give you years of enjoyment.

Because lawns require more frequent watering than trees, trees tend not to reach their full beauty and potential when planted in the center of a lawn. But if you still want a tree within a grass-covered landscape, we recommend removing the grass at least 3 feet from the trunk and root collar in all directions, then cover this dirt with a mulch material such as wood chips. The mulch will keep the grass from expanding back under the tree, as well as reduce weed growth.

Be sure to check your surroundings before you plant. First, look up. Are there utility lines above where you want to plant? Because the minimum height of overhead utility wires is 25 feet, the mature height of what you are planting should be less than 25 feet. Check out the Utility Friendly Trees Garden in the Community Education Garden on Western Avenue for ideas of trees that are appropriate for planting under utility lines. Look at the surrounding area as well. Are there structures or other plantings within the canopy area of the tree? If so, make sure the tree, when full-grown, will be compatible with its “neighbors”.

Most trees and shrubs prefer full sun. Check the light requirements for your new trees. Does your landscape provide sufficient sun for the species you have chosen?

Consider whether a tree is the best choice for the spot you have chosen. A shrub can be a good alternative. A shrub with a maximum height of 20 feet can provide similar benefits to trees, such as privacy, while simultaneously preserving view planes.

Now is a good time to take a careful look at your trees. How did they fare through the winter? Any evidence of winter damage? Do any trees need to be replaced? If so, now is the time to plan for removal and replanting.
By Casey Leigh

How To Graft Fruit Trees Using Budding – 8/1/2017

We get so many questions about backyard fruit trees and it turns out that many people don’t have room for the number of fruit trees they would like to grow. There’s a solution to this backyard fruit production problem. It is called budding, which is a type of grafting.

Fruit trees are beginning to go dormant in August. It may not seem evident from their green lush growth, but their bark has begun doing what is called “slipping.” This highly resembles crepe-y skin on your arms if you are over 60. This loose bark is easy to cut and slip in a wedge of wood to create a new variety on a branch. Here’s how it’s done.

Find a branch about as thick as your thumb. Cut off a leaf bud with the leaf attached. Make the cut a canoe shape. Carefully cut off the leaf being sure not to tear the bud. Keep it moist. Then select a lateral branch that you want to have a different variety growing on (recipient branch). Cut a two inch slash about 12-18 inches from the main stem or trunk. Cut so it barely penetrates the bark and the cambium layer is not cut. At the top and bottom of the 2″ slash, make perpendicular cuts so that the bark easily peels back and doesn’t tear. Slip your canoe-shaped bud into the slit of the recipient branch. Make sure the bud is inserted so that bud growth is headed in the right direction; the graft will fail if inserted upside down. Next, wrap the slit securely to cover all open bark. Be sure to leave the bud uncovered.

To create an airproof closure, seal the branch with grafting wax, paraffin, or clear packing tape or wrap it with rubber grafting strips. Then tie a brightly colored ribbon at the terminal end of the recipient branch. This is essential so that in the spring an enthusiastic burst of pruning won’t result in cutting the damn thing off.

It is astounding how fabulously fast the new variety will create a new branch! However, it’s important to note that successful results require specie compatibility once you jump to genera differentials success drops dramatically.

Tim Smith, our emeritus teacher and extension expert, has created pear trees, apple trees, Asian pears with up to six different varieties on each. This method is also effective for trees which need pollinizers. Rather than having two almond trees, I budded two branches of a pollinator donor on my almond tree.

*Some of the information for this article came from Oregon State University Extension Service.
By Bonnie Orr

Coryneum Blight on Stone Fruit Trees – – 6/1/2017

Stone fruits, such as peaches and nectarines, are often grown in small home orchards. In the late spring and early summer, clients ask us what is causing the holes in the leaves or lesions on the branches of their stone fruit trees. Our answer: Coryneum blight or Shothole (Wilsonomyces carpophilus). This fungal disease was diagnosed in France as early as 1853 and is found on most continents around the world.

Like all fungi, water is the best friend of Coryneum blight. After overwintering in dormant infected buds and twigs, spores produce with the rains of early spring. Depending on temperature, spores can germinate in as few as 4 hours of contact with water droplets during higher temperatures to 24 hours in lower temperatures. Temperatures from 70 to 80 degrees F are ideal for infection. Two to four days after germination, lesions can be seen.

On young leaves, the lesions begin as red spots that become purple with white centers as they enlarge, finally dropping off, leaving the classic “shothole” in the leaf. Cankers can be seen on twigs. Early symptoms of infection on the fruit are a scab-like center spot with a reddish halo that can reach 1/4” in diameter. In the last month prior to harvest, symptoms are sunken brown spots up to 1/2” in diameter on the fruit. Leaf infection can lead to fruit infection as spores spread in times of frequent light showers and wind.

What advice do we give? Start with cultural practices. Use low-volume sprinklers, drip irrigation, or sprinkler deflectors for watering. Prune off lower branches to prevent foliage wetting from irrigation. Prune and dispose of infected areas as soon as they appear. Later in the season, after leaf drop, inspect and prune infected buds and twigs.

WSU includes Coryneum blight on its “Suggested Organic Spray Schedule for Home Gardeners”. It specifically states that sulphur products should not be used on apricots, but are fine for other stone fruits. During the dormant/pre-dormant season, apply lime sulphur, a copper-based fungicide, or Bordeaux mix before the buds swell in the spring. During petal fall or shuck, just as dead flowers fall away from the young fruit, apply copper-based fungicides. In the fall prior to rainy weather, apply a copper or sulphur-based fungicide to prevent Coryneum blight.

Following the above advice will help ensure you’ll have plenty of fruit to eat and to bake those delicious stone fruit desserts with!

Information for this article came from – Coryneum Blight – 2.914;, “Pests in Gardens and Landscapes: Shot hole or Coryneum Blight” (rev. 1/31/17);, E. E. Wilson, “Coryneum Blight of Stone Fruits”, Yearbook of Agriculture (1953); and, WSU Suggested Organic Spray Schedule for Home Gardeners.
By Casey Leigh

Dormant Sprays for Fruit Trees – 2/1/2022

What a wonderful, snowy winter. It looks like the plants are tucked in and protected from the cold. They are dormant. So are all the diseases and insects that prey on the fruit trees. It is a bit early to apply dormant sprays, but it is not too early to plan.

There is nothing as disappointing as seeing red “pimples” on the apricots, misshapen or rot in the middle of a beautiful peach, or picking stunted plums. The very worst is finding a worm in a cherry or apple! This damage can be eliminated by appropriately applying dormant and delayed dormant sprays that will control insect pests and diseases such as overwintering scales, aphids and mites. These sprays are oil based and smother overwintering fungal spores, bacterial blights, insects, larvae and eggs. These insects cause leaf damage such as leaf curl and leave unsightly and misshapen fruit.

Dormant sprays are applied to a bare tree before the buds show any activity. This is usually in late winter when the days are in the 40’s and the nights are above freezing. The right day to spray will vary depending on what part of NCW you live. Delayed dormant sprays are applied a few weeks later just as the buds begin to show the first green tissue when the daytime temperature is between 45 and 55 and no freezing at night.

You can treat your trees with conventional or organic materials. There are three types of spray schedules: dormant, delayed dormant and growing season. You can get the spray schedules electronically by contacting the diagnostic clinic at Provide a phone number in the email so we can contact you and answer your questions.

Often fruit trees have grown so large that they cannot be sprayed with a hose-end sprayer. In that case, commercial spraying is the option. The other option is to treat the tree with a chainsaw at the base. Really, isn’t 200 pounds of plums on a backyard tree a nuisance to deal with?
by Bonnie Orr

Heat Stress on Evergreens – 11/1/2021

Whenever there is a heatwave, people are warned to stay indoors, drink plenty of fluids, and watch for signs of heat stroke: headache, nausea, dizziness, weakness, and so on. People can duck into an air-conditioned building, drink a glass of cold water, or stand in front of a blowing fan. But what do trees do to cope with high temperatures like the prolonged heatwave we had this past summer?

Last summer’s heatwave put a lot of stress on all plants, but studies show that many factors over several years have contributed to decline in evergreens. Back in 2011 bigleaf maple trees were noticed dying in Washington and Oregon. Researchers from Washington State Department of Natural Resources, the University of Washington, the U.S. Forest Service, and Oregon State University tried unsuccessfully to discover the cause for the death of these trees (Oregon Department of Forestry). Recent studies now suggest that increased human development, higher summer temperatures and severe summer droughts, made worse by climate change are linked to the trees’ death

Based on reports from people around Washington, scientists fear other Pacific Northwest trees are also experiencing diebacks (Oregon Department of Forestry Forest Health and Resiliency Division), including our beloved evergreens. Over the summer the Plant Clinic received many “why is my tree dying?” questions. Here is what we know.

Trees absorb water from the soil through their roots. They have an amazing ability to move water from their roots throughout the whole tree. Think of the giant redwoods and how far the water must travel to reach the top of the tree and move all the way out to the smallest needle! If there is enough water for the roots to draw in, there is little chance of heat stress happening.

However, when there are drought conditions, the tree cannot draw enough water from the soil to support the entire canopy. When there is not enough water, the tree will begin to slow its biological functions. This allows the tree to go into a dormant state to stop losing water, resulting in a tradeoff because it also reduces the ability to photosynthesize. A delicate balance is upset. Heat stress results.

You may have noticed the needles of your evergreen trees start to change color, going from a healthy medium green to light green, followed by light pinkish-tan before the needles dropped. In initial stages, only the newest growth on branch tips may be affected, but as drought continues, entire branches or whole trees may die. In conifers, one may see entirely red crowns, red tops and scattered red branches. Once a tree has been weakened by heat stress, it is susceptible to attack by insects and disease.

Here are some things people can do to minimize the effects of summer heat and drought on trees and shrubs:

Water early in the morning to reduce evaporation loss. Trees and shrubs need a good soaking of water at least once a week, especially newly planted ones. A rule of thumb is one inch of water per week in heavy soil and 1 ½ inches in sandy soil. The water should be at the root zone, not at the trunk.

Mulching helps conserve soil moisture. Shredded wood mulch to a depth of 2 to 3 inches is best but should be kept at least 6 inches away from the main trunk or stem. Soaker hoses can be placed under mulch. Before watering, check by poking a finger an inch deep into the soil. Dry soil should get water, but you do not want to flood the plant. In times of drought with elevated temperatures and wind, trees may need to be watered more often than once a week.

Do not fertilize during hot and dry conditions, as it can dehydrate trees/plants or burn the feeder roots.

Avoid pruning, transplanting, or digging plants during stress periods.

Herbicides should not be sprayed when temperatures exceed 80-85 degrees, as these chemicals can volatize, drift, and injure desired plants.

Remember that trees can sometimes lose all their needles and still recover. Sometimes not. The best action if a tree is severely stressed and drops its needles, is to wait and see. It may not be able to survive winter, but it also may recover come spring. In the meantime, when you have a sick tree or shrub, keep it comfortable. Water once a week (unless there is adequate rain) until there is a good frost and put down mulch as described above.

Finally, join with others in doing whatever you can to address climate change.

May we get adequate rainfall and snow this winter to prevent severe drought next summer
by Pat Beeman

How Roots Work – 6/1/2018

In mid-April, a few of the clinicians attended the first seminar in this year’s horticultural series: How Roots Work. We learned so much that we thought we would share some of our newfound knowledge with our Sage readers. This article, like the seminar, represents the proverbial “tip of the iceberg”. Hopefully you will find the topic as interesting as we did.

As we all know, without properly functioning roots, plants cannot grow to their full potential. Roots perform four critical functions: absorption, conduction, anchorage and storage. Roots are divided into two ranks: primary and secondary. Primary roots include taps without laterals, taps with laterals, and fibrous root systems. Secondary roots consist of vertical taps that have been choked out, horizontal lateral roots near the surface (within the top 6” to 24”), oblique roots, sinker roots that grow downward from the laterals, and fine (feeder) roots. Each of these root types serve important and different functions.

A common misconception is that all mature trees have tap roots. Trees without tap roots, such as most fruit and shade trees, have a lateral and fine root system. For trees that do have tap roots, for some, the tap roots eventually die, leaving the other roots to perform their work.

When choosing a tree to plant in your landscape, don’t forget to consider the roots – both their depth and spread. Knowledge of depth and spread are important for ensuring proper soil moisture and ensuring the roots don’t outgrow the area picked to accommodate them. Root mass in a Swiss stone pine (Pinus cembra), for example, is two times the 18 foot height of the tree! Conventional wisdom says that to ensure your tree roots get proper watering, water out to the drip line.

Conventional wisdom isn’t always right. For some trees that could work. But for others, the working roots extend far beyond the drip line. The roots of the Swiss stone pine are 35 feet wide, far beyond the drip line. The amount of light the tree canopy gets affects root growth as well. For example, light availability in an oak forest is 5-20% of the light in a clearing, and for a linden forest, only 1-8%.

Paula spent some time going over the basics of the anatomy of roots, of which my understanding is too rudimentary to be able to accurately and successfully explain here. But it was interesting and I did take away a few facts. Root to shoot ratio is important. Plants need to balance root and shoot growth and the plant hormones auxin and cytokinin assist in this process.

Plants have interesting defense systems, including a Casparian strip in the cells that prevents passage of substances through portions of the cell wall. This is particularly important in regards to pesticide absorption and movement. Water absorbed by the roots can carry many types of dissolved substances, including nutrients and pesticides.

Thank you to Paula for continuing to offer us interesting seminars that increase our knowledge base as master gardeners.
By Casey Leigh

Insect Pests Prepare for Winter – 10/1/2019

As summer winds down and cooler autumn temperatures descend upon our landscapes, many of us begin the tasks of prepping our gardens for the winter. This list can include planting garlic, mulching tender plants, cutting back herbaceous perennials, protecting young conifers from hungry deer with netting, or blowing out irrigation systems.

Meanwhile, many insect pests are preparing for winter too. Where do these insects go, and how can our actions in our environment influence this? This is a big question and I’ll focus on just three examples that are relevant this time of year.

I am often asked, “I have an apple tree but don’t want to spray it. How can I keep worms out my apples?” The short answer is, you cannot. However, if you understand the life cycle of the codling moth (the “worm”), you can take several steps to minimize damage. Codling moths can have 2-3 generations per year, but most damage is noticed in the fall when it’s finally time to harvest apples. Adult moths lay small eggs on the apple surface. Once hatched, a tiny larva will begin eating its way toward the core where it will feast on the protein dense seeds until ready to pupate. The moth larva will then eat its way back out of the apple, leaving behind a much larger and messier hole. The caterpillar finds a protected place within the bark of the tree or even in the debris at the base of the tree and pupates. This summer’s last generation of codling moth is doing this right now, and will spend the winter in this state.

The easiest action an apple tree owner can take to stop the cycle is culling all damaged fruit throughout the growing season, but especially in the fall. This means picking any apples with signs of codling moth damage as soon as possible and disposing of them in a sealed plastic garbage bag. Clean up any apples that you do not intend to harvest or that have fallen on the ground. Additionally, a band of corrugated cardboard, stapled snuggly around the base of the tree is a great place for codling moths to pupate. Remove the band in November and dispose of it.

English walnut is another common backyard tree in our area and seeds are beginning to fall from the trees. Walnut trees are often too large and difficult to spray without the help of a professional and can become infested with walnut husk fly.

This fly emerges from the ground mid-summer to mate and lay eggs under the skin of the walnut husk. The maggots feed on the tissue of the husk, which rots into a squishy black area that will stain the surface of the walnut. Mature husk fly maggots drop into the surrounding soil and pupate under ground until next summer. Once again, cleaning up all walnuts and seed husks as soon as they drop will drastically help prevent recurring infestations. Several tarps can be staked under the tree canopy for easier col-lection and serve as a barrier between maggots and soil.

Throughout the heat of August I usually experience a bit of “garden burnout”. It’s just too hot to fuss around in the vegetable garden, and frankly I’ve stopped caring. The best I can do is to harvest what I absolutely need and check that the water system is still running. And then … spider mites

Hot dry weather is when these plant pests thrive and I have the green beans to prove it. They don’t fly. Where do they come from? Spider mites overwinter as mated females within the soil, leftover garden debris, or on perennial plants. As early as March these females are making their way to fresh leaves to lay eggs. Populations often remain small, sporadic, and unnoticed until they explode in late summer. While some pest tolerance is acceptable, especially on an annual crop, a severe infestation can significantly reduce your late summer harvest and blemish your produce.

Thoroughly removing vegetable plants as soon as you’re done with harvest will help prevent this cycle from happening. Additionally, pull any perennial weeds in your vegetable area that may harbor spider mites through the winter. All debris should be hot composted, burned, or otherwise disposed of properly. Females are beginning their transition right now, so it’s time to get out there and be diligent in your fall clean up!
By Tawnee Melton

Irrigation: to Drip or Not to Drip? – – 12/1/2019

Some of the horror stories we hear and see at Clinic involve trees and related drip irrigation systems.
The client’s initial intent to use a drip irrigation system to water newly planted tree(s) may have been a reasonable choice at the time. However, they tend to set-it-and-forget-it, thinking it a permanent solution to the tree’s need for its life blood. Often only a couple of drip emitters are placed near the trunk on opposite sides of the tree; then there are multitudes of time-and-volume stories of how they were used. (To clarify the typical scenario, these are growing trees set in landscape berms with no other supplemental irrigation beyond nature and a drip system.)

Time passes, all seems well, then, when the calendar flips to the tree’s 3rd to 5th year after transplant, the Clinic starts to get visited by disturbed clients with woeful stories of distressed trees. At this age, two prominent problems are diagnosed: first is planting depth (but that is another story), and second is irrigation.

With the second problem being the subject of this article, I offer the following side note: Water can be a tree’s best friend or its worst enemy. As the enemy, over-watering is one of the primary causes of tree death. In the case of inadequate water, a tree becomes distressed but salvageable.

So now the client gets the news that their tree has outgrown their simple, care-free, affordable drip-irrigating system. They also learn that if they want to retain a drip style of irrigation system, they will likely experience the need for several more irrigation expansion projects. Many of the clients seem shocked to learn that their tree’s feeder roots grow to reach a much broader area than they had expected to irrigate. (Right tree in the right place???)

Wham! Bam! Sticker shock! Now comes the flood of questions all rolled up in a general topic of, “Now what do I do!?”. Since most of the questions hit upon an inexact science, the Clinic’s response has to be “It depends—”. Here is a sampling of how the Q & A sessions might evolve.

Q. How should I water? A. It depends on the water resources available. Your preference of Drip, Sprinkler, Soaker Hose, Rill or Basin surface water flooding covers most choices. However, in every case, you should consider how to avoid water run-off due to slope of ground and your soil’s percolation capacity (ability to absorb and distribute water).

Q. Where should the water be applied? A. It depends on where the feeder roots are well established, which can be a moving target over time; however, the general target area is a broad band circle of the entire tree from a couple of feet inside the drip line of the developing canopy up to an area beyond the drip line of the canopy that represents a point to where the top of the tree would be if it were to fall over. This practice provides for growing a strong, healthy, expanding root system.

Q. How much water does a tree need and how often? A. It depends on the variety of the tree, the texture make-up of the soil surrounding the tree within the irrigated area, the water holding capacity of the soil, and the time of the year (related to the evapotranspiration rates of the water from the soil and leaf canopy due to temperature and wind). Other issues to consider are the existence of mulches and weed barrier cloths. The definitive amount of water is bound in the word “adequate”, which generally means moist soil to a minimum depth of 12 inches. Moist soil means that a handful of the soil, when squeezed firmly, will hold in a firm clump, but no free water can be wrung from that squeezing. Resupply water when the top 3 inches of soil has dried, which could be as often as weekly, or no longer than 14 days, depending on weather conditions. Established trees prefer deep infrequent watering to allow their root system sufficient access to oxygen. A handy tool to have would be a 24 inch soil core probe for accurate moisture profile testing. Seasonally, the first application of the year will take the longest time to establish the depth of coverage.

Q. What is the best time of day to water? A. It depends on when water may be available due to source restrictions, if any. But, for most efficient use of water, it is best to avoid as much residual evaporation from very warm prior days with a target time between 3 a.m. and 5:00 a.m. This allows for water seepage to reach some depth before the new day’s evaporation begins.

For the answer to the topic question of “Trees: To Drip or Not to Drip?”: It depends’ on your preference, but considering the number of drip emitters and the time required to deliver the volume of water to the depth recommended for heavy users of water, while at the same time fighting evapotranspiration rates of thinly applied moisture, efficiency would imply the latter a better choice.

Love your trees!
By Keith Thrapp

Right Tree/Right Place – 12/1/2018

This is not a scary season just because Halloween was a couple of weeks ago. However, it is the season where homeowners can be tempted to make decisions that will haunt them for years to come.

We have had a radiant autumn. Haven’t the fall colors been beautiful? Susceptible people drive through neighborhoods and see a particularly lovely tree, or an arbor collection and think, “I have got to have it. I have always loved that tree!” Master Gardeners often are called upon to provide solace to a homeowner whose tree most likely should be removed because it is the wrong tree in the wrong place.

The wrong tree in the wrong place occurs for a number of reasons. First is infatuation with a particular tree. Second is the feeling that an empty space must be filled immediately with trees that hopefully will grow very fast. The third reason is the most critical: trees are predetermined by genetics to grow to a certain size, and when mature, say after 12- 20 years, they will have outgrown their space.

The size issue is a big one in NCW. We have so many people who make their living around trees and have mastered fruit tree pruning skills. So people are available to top a tree, or to limb it up or to lower the center of it.

Frankly, this does not alter the final size of the tree. It just makes it cranky because cutting off the top, or the center, or the lower branches causes two problems. The first is that the tree is made vulnerable to disease and insect predation because of large wounds in the wood. Secondly, the tree responds to cutting by creating vast numbers of smaller, whippier branches that are not as securely attached to the tree and can more readily be blown off in a wind storm.

So, the final word is determine how big the mature tree is before planting it in the site that will allow it to grow to its natural size. A number of favorite trees, especially conifers, have been bred to be a smaller or compact size when mature, and these specimens might be a best choice for a smaller yard.

The second most prevalent problem with the wrong tree in the wrong place is the urge to overplant with special species to fill in a newly landscaped yard. One of my friends is facing two dilemmas at the front of his house. Growing in an area 10 by 20 feet are mature Hinoki False Cypress, Western Juniper, Yew and Engelmann Spruce. This forest grows right up against the house and obscures a beautiful rock wall. The trees need to be whacked back to get to the front door. The most serious dilemma is the need to consider firewise landscaping. The conifers grow right under the eaves and would guide a fire up into the attic. Worse, they extend beyond the roof and are 12 feet from the fireplace chimney. These trees were beautiful specimens years ago when they were planted by the homeowner who did not consider the mature size nor the liabilities of the wrong tree in the wrong place.

Infatuation causes people to make unwise tree selections. They do not consider size nor maintenance. Trees really do not thrive in planter boxes. Many of fall’s colorful trees are deciduous. Do you know that a mature maple has over 100,000 leaves? Not all leaves are created equally. Some, like elms or small leaf linden, are small and compost readily. Ash trees drop their leaves and then thousands of little branches. Other leaves like oaks have a waxy coating that takes a long time to compost. In addition, some brown oak leaves persist on the tree all winter until the spring growth pushes off last year’s leaves.

Considering the entire year’s growth pattern is important. Scotch pines spend the entire year shedding vast amounts of pollen, then male cones, then female cones and finally needles. Other messy trees are magnolias that shed flower petals, seed heads and leaves over most of the year.

So when neighbors or friends ask your advice about what tree would be perfect for their landscape, do as we do in plant clinic – teach them about “right tree in the right place”.
By Bonnie Orr

Select and Plant Trees and Shrubs – 3/10/2024

The weather is warming and many people feel the urge to buy and plant woody shrubs and trees. I’d like to address buying and planting woody plants and trees. Consider those urges. Most people know we should not go grocery shopping while you’re hungry, so don’t go to nurseries without knowing what you are looking for. Of course wandering through ogling beautiful plants is enjoyable. However, buying a flat of marigolds or other annuals is not the same as purchasing a tree. One will live a few months and take little care, the other can live for years and may need much more care.

Find out the mature height and width of your potential tree or shrub. What are environmental needs of this plant i.e. –  do you have the correct amount of sun/shade, and can you supply sufficient water for its needs? Can it tolerate our ever increasing summer time temperatures? What is the soil type of the location for planting your woody shrub? Is it sandy or clay, rich loam or glacial till? The soil type determines your watering regimen.

Selecting your plants:
It’s important to inspect bagged and burlap potted woody shrubs and trees prior to purchase. There are two important things to look for. You should see the root flare (where the stem meets the roots). As the word suggests, the stem flares out. This is important because soil or mulch should not be in contact with the stem. Planting too deep restricts the amount of water and oxygen to the fine root systems, lowering the trees vitality. Trees planted too deep are also more subject to canker development and wind throw.

In order to find the root flare and see potential problems on the stem, such as stem rot, you may have to gently pull back the burlap and have a look. Reject any potted plant where you can not find the root flare or you find injury to the stem. The same advise for plants in pots that are growing significant amounts of weeds. Weeds indicate the tree/shrub has been in the pot a very long time.

Bare root plants do not have these issues. But they should be inspected to see how many living roots are encased in the plastic wrapper.

Planting Your Plants:
Be prepared to plant soon after purchase. If not, place in a shady area and get back to planting in the very near future. Do not try to plant in the heat of summer or before the soil warms to at least 60 degrees in the spring.

Bagged and potted plants will need to have the roots loosened and the potting media removed prior to planting. All woody plant roots grow outward. Wash off the potting media. Soaking the root mass in water can help loosen this material. Hose off the rest. Once the material is off, inspect the roots. You want to see roots spreading outward, like the spokes of a wheel. Think of roots like branches. If a branch is wrapped around the stem, it will continue to do so. So unwind or cut off that circling root and   “J” roots. “J” roots look just like the letter. If you can not straighten them out, cut them off. Circling and “J” roots adversely affect the long term health of the tree or woody shrub.

Here are photos of before and after pruning. The following photos provide better graphics of what I am talking about. You most likely will not encounter such large roots.

Once this is done, it is time to plant. The hole should be more or less a bowl shape, with a slight mound in the center to place the tree on. The root flare will need to be at the surface level. Do not add amendments such as fertilizer, leaves, peat moss or compost to the hole. Plant roots need to grow only in native soil. Fill in around the plant roots with the soil which you removed when digging the hole.

Any remaining soil can be mounded at least 2 feet around the perimeter to hold water. Water well. Do not stomp on wet soil. Good, deep watering will settle the soil around the roots and eliminate air pockets. Check to make sure the soil has not subsided lower than the root flare and the tree is sitting at surface level. Have on hand adequate mulch material to spread at least 4 inch deep around the tree or shrub, but not touching the stem of the tree or shrub. This depth will help prevent weeds from popping up and protect the woody stem from injury from lawnmowers and trimmers.

Bulky wood chips are best. Keep in mind tree roots can eventually extend horizontally one and a half times the height of the tree so avoid placing the plant near your house/garage or driveway. Keeping this area mulched goes a long way in conserving water, keeping down competition, avoiding injury and maintaining cool soil temperatures. Be sure to keep your plant well watered as spring turns into summer. Deep watering is best – fill that mounded area with water. Pay attention to soil moisture and do not let it dry out during the few seasons. This is important even for drought tolerant plants. After a few years, watering can be reduced.

Finally, do not prune off any branches for the first three years unless they are rubbing against each other. It is not true the branches will interfere with tree establishment. Branches and their leaves are what will nourish root growth and therefore improve tree health and establishment. If, in the spring you see a dead branch, it can be removed.

Enjoy your new addition. I hope it bring you years of pleasure. If you have questions, feel free to connect with us at:  “The Garden Professors” is also a great source for information. They have a blog and Facebook presence.
By Emilie Fogle

Spring Pruning Tips – 3/1/2016

Do you have a lilac that only blooms up by the roofline? Was that Forsythia a mass of yellow joy a few springs ago but has a few weak, yellow blooms? Has your Rhodie gotten too big and forgotten how to bloom? All of these garden woes can be corrected by pruning these multi-stemmed shrubs.

Use the correct, sharp, clean tool. Use pruners for cuts ½ inch or less. By-pass pruners allow you to cut closer to a trunk or main stem; anvil pruners are easier to use but cut by smashing the plant tissue. For stems ½-1 inch thick use loppers. For stems over 1 inch thick use a pruning saw that is thin and slightly curved to fit into tight spaces. Forcing a tool not designed for the diameter of the stem causes serious stem tearing and damage and hurts your hands! Have all three tools with you before you start cutting.

Cuts are made at a slight angle — about 20% — so water doesn’t sit on the cut and rot the stem. If the cut is too slanted, the cut cannot heal. Cut about ¼ inch above the bud you want to grow into a lateral branch. Longer “stubs” invite disease and insect damage to the plant.

June is the last time to prune spring flowering shrubs because they begin to form next year’s blooms by the beginning of July. As a general rule, native bushes such as serviceberry, chokecherry or elderberry are not pruned. But the methods below will work to limit the size of these plants.

Pruning is not whacking away at the branches that are too long and in the wrong place. The first step in any pruning job is to take out the broken, spindly, diseased or rubbing stems. When only the ends of the branches are cut back, the pruning technique is called heading back and is used to keep a shrub dense and compact, not necessarily made into a little ball.

Make cuts of different lengths to retain the shrub’s natural look. This pruning is done annually immediately after a shrub has flowered. Only a few inches of plant material is removed to maintain a shrub’s particular size. Deadheading last spring’s flowers is a type of heading back and promotes lateral branches that flower. So deadhead for aesthetics and also for next year’s flower production. Do not head back native plants — it will just make them mad and eager to get even.

So, you have been meaning to cut back that shrub, but there are so many other things to do and the loppers have gone missing. Now after a few years of neglect, the plant must be pruned differently to restore it. Let’s talk about that lilac that blooms so high you can’t see nor smell the flowers. What is to be done?

It will take three years; then you will have a totally new plant that you can head back annually. The technique is called thinning. There are two types of cuts made on the oldest stem (the bark is gray and perhaps a bit raggedy looking).

1. Cut one third of the oldest stems to about 4 inches high. This forces the plant to produce lots of new growth at the lower part of the plant to fill in the “blank” part of the stems.

2. Cut 1/3 of the oldest canes to the ground. This promotes new stems from the roots of the plant. Thinning lets more light into the plant and that promotes more blooms.

The Forsythia that has lost its glamor can be restored with a technique called rejuvenating. This method takes courage, and you may want to enlist the help of a trusted gardening friend to do the deed. Take a saw and cut the entire plant to the ground. Go inside and have a cup of tea.

The plant will recover—this season—and likely will be filled with blooms next year. (This works really well in early spring to keep Buddleia under control.) Use this technique as a final solution because some shrubs will pout for a year before they think about blooming again.

Spring blooming shrubs that would appreciate your attentions with the pruners this week are:
Forsythia, Viburnum, Weigela, Lilac, Azalea, Rhododendron, Ninebark (Physocarpus), Mock Orange, Beautyberry (Callicarpa), Carolina Allspice (Calycanthus), Red-twig dogwood, Spiraea Fairy Dusters (Kerria), Rose-of-Sharon (Hibiscus syriacus), Flowering quince, Smokebush (Cotinus), and Pussy Willow.
By Bonnie Orr

To Mulch or Not to Mulch – 11/1/2017

To mulch or not to mulch — that is the question.

First of all, what is the purpose of fall mulch? Mulch will help preserve groundwater for the winter so a plant’s roots will not desiccate as rapidly. In addition, an application of mulch on bare soil will slow down or eliminate erosion from water movement or heavy rains. Mulch will prevent the growth of annual weeds in early spring. Finally, the most common use of mulch is to protect tender roots on newly planted trees or shrubs.

Timing of when mulch is applied is up to the gardener. To protect the soil and to prevent desiccation, the mulch should be applied before the temperatures fall into the 30’s and before winter storms arrive. We have always anticipated snow storms, but with the new weather patterns, we are experiencing winter rain more often than before.

Two theories posit when to apply mulch. The first says mulch should be applied before the ground freezes to keep the ground from freezing. When the ground freezes, small roots can be broken by the frost heave. Or, the mulch can be applied after the ground freezes to prevent it from freezing and thawing a number of times since this causes roots to break. There is no clear consensus on which way is best. Preventing rapid fluctuations in soil temperature is the bottom line. Often the choice between before and after is based on what your dad or grandmother did in the fall in the garden.

What are mulching materials? Evergreen branches work well and can also provide harboring areas for small birds and rodents. Straw, chipped leaves, wood chips and ground bark are the most common materials used in this area. We do not often see people who mound dirt around roses, for example. If there is enough loose soil in your garden, you can use the soil mounding technique. The application process is critical. All mulches should be placed 6-8 inches deep and TWO inches away from the stem or trunk of the plant. Mulch will be removed in early spring. Most organic materials will have broken down somewhat and added organic materials to the soil structure.
By Bonnie Orr

Tree Borers – 11/1/2019

A recent addition to the plant clinic insect collection is the locust borer Megacyllene robiniae. This particular specimen was found wandering inside the Cooperative Extension office. A log of black locust resting against a file cabinet with tell-tale signs of borer damage was soon discovered as its origin.

Chelan County is home to many species of tree boring beetles. Some of these beetles target a single species of tree, while others will reproduce in a hand-ful of similar hosts. For example, the red headed ash borer, Neoclytus acuminatus, favors ash trees but will also attack oaks, hickories, or almost any stressed hardwood.

In fact, most tree boring beetles are only attracted to stressed or dying trees and often cannot survive in a healthy thriving tree. Adult beetles lay their eggs on the bark of target trees. Larva emerge and begin feeding underneath the bark and usually overwinter in this phase. In the springtime they will continue to feed and tunnel through the sapwood and hardwood until they pupate and emerge as an adult beetle. Depending on the species there can be multiple generations per year, or a single larva can spend years within the tree before pupating.

Here are the key ways to protect your trees from tree boring beetles:

Plant trees properly in suitable locations and maintain tree health and vigor with adequate water. Avoid other stresses such as root damage or soil compaction.

Plant tree varieties that are more resistant to the tree borers that live in your area.

Avoid pruning or making large cuts to trees during the months the adult beetles will be active, as this will attract them to your tree.

Watch for signs of infestation and treat with the recommended pesticide. Signs of infestation can include exit holes in the bark of your tree, tunneling patterns when bark is pulled back, weakened limbs with dieback that break off easily in the wind, woodpecker activity, and sometimes trees can display suckering on the trunk below borer activity.

If you’d like to see some borers up close and personal (and no longer living), drop by the office and check out our insect collection.
By Tawnee Melton

Viburnums: Big and Showy Shrubs – 3/1/2013

Last month my column discussed the little guys–dwarf conifers. This month I’m delving into bigger shrubs — specifically viburnums; showy and vigorous with many attributes.

There are plenty of viburnums hardy enough for our climate. Take your pick as to what’s important — masses of spring flowers, summer berries, fall color, textured leaves. In addition to these pluses, they are nice for screening unsightly areas and great as back-of-the border shrubs. Most of them need plenty of space; they’re not known as being shy and refined. Come fall, birds will appreciate those berries, but generally viburnums are not self-fertile, so with just one shrub, you’ll get flowers but not necessarily berries.

In our climate most are deciduous, although a few really hardy ones like the hybrid ‘Eskimo’ might over-winter in a semi-evergreen state.

We planted a Viburnum plicatum tomentosum ‘Mariesii’ near our backyard fence, and late spring its impressive display of white lacecap flower heads sprinkled along horizontal branches is simply stunning. No berries on this one though. Most gardeners call this group just doublefile viburnum rather than by its Latin moniker. In addition to this dramatic spring performance, it screens out the background, as it grows six or more feet tall and even wider. Being deciduous, bare branches don’t do a lot for winter screening, but summer is really when screening is most important anyway.

Ours gets full sun, a bit of fertilizer in the spring, and is on our regular border irrigation system. I cut out crossed or dead branches, but otherwise pretty much let it do its own thing. Pretty trouble free as far as I’m concerned.

Spring is a good time for planting shrubs. Dig a hole no deeper than the container, and one or two times wider. Trim off or untangle any roots going around the pot, situate it in the planting hole with its best side forward, then tamp in soil and water in.

V. carlesii or Koreanspice viburnum, is known for wonderful spring fragrance when those pink buds open into white flowers. It’s ideal with a little light shade during our hottest months.

There is an evergreen viburnum that can tolerate our cold, V. rhytidophyllum or leatherleaf viburnum. It has a somewhat coarse look and can grow quite tall and wide. It sports long, narrow deeply-veined leaves and has less impressive flowers than most in this group, and takes more shade. In cold weather the leaves droop, much like rhododendrons, and leaves become tattered in cold winds.

V. opulus or cranberry bush is extremely hardy, vigorous and sports great fall coloring. If you’re searching for a large shrub or two and viburnum’s attributes strike your fancy, do a little homework to select just the right cultivar for your landscape.
By Mary Fran McClure

Watering Tips for Your Garden and Lawn – 8/1/2016

During the summer months, a common problem we see are plants suffering from either over or under watering. Many home gardeners adopt a set watering schedule that doesn’t accommodate their soil type, the varying root structures of their plants, or changes in air temperature and humidity.

It’s important to keep in mind that plants that are over or under watered will be more likely to suffer insect damage and be more susceptible to disease as the summer progresses. Stress from poor watering practices can also have a negative effect on winter hardiness. This article covers the ins and outs of watering home gardens, turf areas, and ornamental plants.

Factors to consider when planning your garden’s watering schedule include soil type, air temperature, time of exposure to sunlight, and the specific needs of your various plants. Clay soils take longer to absorb water than sandier soils, but dry out slower. The converse is true for lighter soils.

Hot, dry air increases water evaporation from the soil and transpiration through the plant’s leaves. Plants in a sunny location will lose water faster than those that get more shade. So also will those planted near the house and with southern and western exposures. I was surprised to discover that a large tree can lose hundreds of gallons of water in one summer day!

An effective way to ensure adequate watering is to water the root zone thoroughly and re-water after the soil partially dries out. Be sure your watering covers an area that goes to the outer edges of your plant. Keep in mind that shrubs and trees have deeper root systems than smaller or more recently planted plants. Therefore, you can water them less often. Gardeners have to do their homework to know how long it takes to completely moisten a plant’s root zone and how deep you need to test the soil for drying out before re-watering. Unfortunately, a “one size fits all” motto doesn’t work in your garden!

While drip type irrigation is recommended for ornamental plants, overhead sprinklers work best for turf areas. Because deep roots create healthier turf and can better withstand drought, it’s important to water a lawn thoroughly and before it begins to dry out. A sign that your grass needs watering is that it stays flattened when you walk on it, rather than springing back up. In addition to the factors above that affect watering, the amount of thatch in your turf area has an impact.

As a rule, avoid frequent shallow watering as it leads to shallow roots which are more susceptible to drought stress. To conserve water, the best times of day to water are at night or early morning. Place plants with similar water needs in the same area. Learn your soil type and your plant’s water needs. Watering correctly will make for happy plants and a happy gardener!

The information for this article came from WSU Publication EB1090, “Watering Home Gardens and Landscape Plants”. It is informative and easy to understand.
By Casey Leigh

What’s Wrong with my Dogwood Tree? – 7/1/2017

It is July and our most common question is: ” What is wrong with my dogwood tree?”
Dogwood trees that are native to the Southeast grow as an understory tree. In Georgia, in March, there is nothing more beautiful than the white blossoms peaking through the overhanging branches of the Lob-lolly pine. It grows as an understory tree.

Here in NCW the dogwood is one of the most popular ornamental trees — and people have planted a wide number of Cornus floridia varieties that grow pink bracts from very pale to deep, deep pink, and some people appreciate basic white.

Nearly all the dogwood questions are exactly the same. All the samples have leaf scorch. The edges of the leaves are crispy brown and a line inside the scorch has turned deep burgundy. The reason that we see so many clients with questions about their dogwood tree is that nearly all of the trees are planted as a landscape focal point dead in the center of the lawn in full July sunshine. This understory tree is trying to protect itself and does so by limiting the amount of leaf volume it has to support.

The critical information that we share with our clients is that you cannot apply more water to stop the leaf scorch, and there is no way to revive the affected leaves. The tree’s leaves are affected because the tree does not have the physiology to take up enough water to each of its leaves to keep them hydrated. Many well-meaning homeowners actually cause serious damage to their trees by applying surplus water to their lawns, hoping to keep the tree from drying out. The most serious result is that root rot will occur.

When you drive around Wenatchee, you can spot the lawn-centered trees that have been overwatered and have some degree of root rot. The evidence is the dead branches sticking up at the top of the tree.

So what do we tell our clients? We tell them to relax in the shade of the dogwood tree and have a glass of lemonade. For there is nothing to do to bring back to life the scorched leaves. The problem will not even be noticeable next spring when the bracts burst forth and the leaves unfold.
By Bonnie Orr

Why Fall Leaves Didn’t Fall – 2/1/2023

Why did the leaves stay on my trees this fall?” This is a common question we have been fielding from both clients and Master Gardeners. That question gave us the opportunity to learn more about the actual process that trees go through when they shed their leaves in autumn. Here’s what we found out.

When temperatures begin to drop in autumn, leaves stop producing chlorophyll. Simultaneously, they begin to develop “abscission” cells that are responsible for shedding of the leaves and sealing up the stem attachments. In deciduous trees, abscission of the leaves is dramatic, turning trees from their full -bodied shape into the stark beauty of their winter skeletal form.

Abscission also occurs in evergreen trees, but much more gradually throughout the year. These abscission cells develop at the base of the petiole, creating an abscission zone or layer of thin-walled cells. As daylight decreases in the fall, chemical changes cause the abscission cells to separate, weakening their bond to the branches. Before long, their own weight, wind blowing through the trees, or rain causes the leaves to fall to the ground. Leaf scars left behind on the branches form a protective layer.

So, what happened this fall? The most likely explanation is the weather. A severe cold snap can cause the leaves to die and turn brown before chlorophyll production decreases and the abscission process begins. Similarly, warm temperatures that linger well into the fall and early winter prevent leaves from producing abscission cells.

Without these thinner cells designed to weaken the leaves’ attachment to their branches, they hang on long past normal. Fortunately, the trees will still produce new leaves as longer periods of daylight and the warmer temperatures of spring reappear. The old leaves will still fall off, adding the autumn chore of raking leaves to the spring list!

For more information, on the process of abscission, see “Tree Leaves Didn’t Drop in Winter: Reasons Why Leaves Did Not Fall Off a Tree”,; “Abscission in Plants”, Abscission in plants: Current Biology (
By Casey Leigh



A Closer Look at Weeds – 5/1/2021

“Yee-oow!” I hear a yell of pain from outside my kitchen and pause my dishwashing, “Is everything OK?”

Our nephew Michael, a solid 13-year-old visiting from Oregon, holds out his hand to me. “Look what I stepped on!”, his eyes wide in disbelief. I glance down, half expecting to see a bee missing its stinger. Instead, I see a rather good-sized pointy thorn familiar to anyone who lives in eastern Washington. “Oh, sweetie, that’s a goat head, it’s a weed we get around here.” Michael looks at me appalled by my obvious lack of concern. “What?! This is a weed?!” At that moment I realize Michael has never been a victim of the infamous puncture vine.

Most anyone who has lived, or visited, eastern Washington has at least one memory of stepping on a bur from the puncture vine or goat head as they are commonly known. My husband, not so fondly, tells of the time he went over his mountain bike handlebars straight into an area covered with “goat heads.” Luckily, he landed on his hands instead of his face. Lucky? Not so lucky? My brother-in-law, also from Oregon, says the bur “hurts way more than it should.” I too, remember stepping on a bur that had lodged itself in the carpet and managed to dislodge itself into my foot in the middle of January. No season is safe from those little buggers!

As spring begins in the beautiful Wenatchee valley it is time once again to prepare for the nemesis of all gardeners, weeds. A weed is generally defined as any undesirable plant that competes with what we want to grow in a particular area. One year my Grandma decided her abundant Hollyhocks were a weed and wanted every one of them gone. She felt the tulips were suffering and preferred those to the Hollyhocks. Weeds pull nutrients from what we want to grow and quite frankly sometimes appear to grow in Superman mode. Or is that only in my garden? Oxalis, Prostrate or Spotted Spurge, Crabgrass, ugh Crabgrass, are but a few plants considered weeds in our area, as well as Purslane and that disreputable Puncture Vine.

Weeds are really kind of amazing. Pause for a moment the next time you lean down to pull one out of your garden. Notice how many are in the space where you are working. How fast they seem to grow, one day you walk by and tell that unwanted plant, I will get you tomorrow my pretty! The next day you find the plant brought in reinforcements. Weeds produce an abundance of seeds and have a hasty reproductive cycle. They are adaptive and ambitious in their growth. Weeds also like to grow in disturbed soil, or soil that is doing poorly, or soil that is healthy, or soil that has not been disturbed, basically any soil that can or can-not grow anything will surely grow a weed.

Oxalis, or creeping woodsorrel, is a weed that I struggle with in my strawberry garden. It is a low growing, spreading plant with shamrock-like leaves, similar in appearance to clover. The leaf color varies from green to reddish-purple. Oxalis is a broad-leaf perennial.

It is widely adaptable and commonly grows in landscape areas, yards, containers, orchards, flower beds, ground covers, fields, generally anywhere you do not want to see it. Oxalis also grows year-round in some areas and produces a cluster of yellow flowers. A tiny and cute blossom until you realize that when the seed pods from this plant mature, they rupture, think explode when dry, and can expel seeds up to 10 feet away. Since the seeds are rough, they pretty much stick to anything which provides easy transportation to say, your strawberry garden? Did I happen to mention their expansive root system? Or that they should be considered toxic because of the oxalates? Your best bet for getting rid of Oxalis is good old-fashioned pulling, rototilling, and hoeing. Something we gardeners are all to used to doing. In addition to hand controls, try to catch this weed before it flowers and sets seeds. With an exploding seed pod, you will want to stay ahead of Oxalis spreading.

I never considered how many weeds were toxic until I sat down to write this article. I have a gravel driveway and battle spotted spurge every year. The first time I saw spotted spurge it reminded me of the puncture vine. Spotted spurge grows close to the ground forming a dense mat, much denser than the puncture vine though. It grows from a central tap-root and a single plant can span up to three feet across, trust me I have seen this, and it is not pretty.

Broken stems of spotted spurge produce a milky, poisonous sap that is an eye and skin irritant, toxic to some animals, and highly toxic to sheep. Hortsense describes it as having “hairy stems and hairy, dark green leaves with a purple spot on each leaf.” This summer annual likes full sun and of course, “produces seed quickly and prolifically.” Each plant can produce thousands of seeds and wouldn’t you know it, like to adhere to most surfaces. Your control methods for spurge are to remove the plant as soon as you see it. Gloves are recommended as the sap is a skin irritant and it is also sticky making it hard to wash off.

I do not know about you, but I also like to wear gloves when I am pulling the crabgrass out of my vegetable garden. Crabgrass germinates in spring and grows quickly throughout the summer. Right around the same time as your garden, landscape plants and manicured lawn begin to ramp up. It is an annual grass with “flat leaf blades which are relatively broad, long and sometimes hairy” but can also be smooth. Crabgrass “is prostrate and may form mats.” I am not sure how crabgrass looks on your property, but it thrives on mine and left to its own devices grows a thick mat. With our gravel driveway, fruit trees, yearly pumpkin patch, and lawn it seems like we have every desirable attribute for weed growth. While it may seem tempting to mow over the crabgrass in your lawn, it is not recommended. Even if you mow it short, say a ¼ to ½ of an inch, it can still produce seed. Those seeds can also remain viable waiting for the right moment to creep up through the soil when you least expect it, most usually for me under my zucchinis.

Last year my Mum and I were weeding my zucchini garden when we came across purslane. It is an annual broadleaf with “fleshy red stemmed succulent with green leaves.” Purslane looks like a little jade plant with yellow flowers. It feels slightly rubbery and to me, always feels slightly cooler to touch. Purslane has blunt leaves and can also form a mat. Purslane produces tiny seeds, but stems can re-root when broken, much to the chagrin to those of us who garden. If you plan on pulling purslane, be sure to grab all those broken fragments laying around and watch out as those stems “are brittle and break easy.” Purslane is edible and has uses as a vegetable, but high oxalates can be toxic. When Mum and I were pulling purslane out of my garden she told me that my grandparents used to prepare it as a tea. It also has uses in salads and is said to be comparable to spinach. Due to the oxalates care should be taken when ingesting. Purslane also grows in healthy soil as well as dry, it is also drought tolerant so once again a “weed” that is highly adaptable.

Another weed that can grow in dry areas is the puncture vine commonly known as a goathead. It is an annual broadleaf that grows from a taproot. The trailing stems can grow up to six feet and “are green to reddish color.” The puncture vine has small yellow flowers, and the spiny burs are separated into sections. Leaves of the puncture vine also grow opposite to one another on the stem. The spiny burs are sharp and can puncture skin as well as bike tires and even vehicle tires.

The burs are shaped so that one sharp point is always facing up. Therefore, it can always impale itself into everything from your feet to your car and because of this the puncture vine is able to travel distances. The leaves are toxic to animals, especially sheep and it can spread quickly. The puncture vine dies at the onset of winter, but the seeds start new plants come spring. It can start flowering within weeks of germination and flowers can bloom from late April until October. Due to its difficulty to control along with its destructiveness the puncture vine is listed as Class B noxious weed. The B classification means it is a non-native species and infestations are a high priority. Hand pulling is recommended and contained hoeing can be done in spring. Care should be taken if the seeds have already fallen to prevent continued infestation. Be sure to wear gloves and check your clothes as well as your shoes to prevent those goatheads from impaling and spreading.

I know for me, even despite the challenges from various weeds I love my gardens. Weeds are like a side note for me, yes, I get them, but did you see how good my garden looks? Plus, there is something invigorating in knowing what plants I am battling for garden space and on our property. Oxalis in the strawberries, spotted spurge up the front of the driveway, crabgrass and purslane near the zucchini, and puncture vine behind the garage. I am so much more knowledgeable than when I planted my first tomatoes. While I do not relish the idea of possibly finding a new variety of plant attempting a hostile takeover in one of my gardens, part of me feels like, bring it on! I got this! Admittedly I do not say it too loud as I would not want the seeds of weeds to hear me.

“In every gardener there is a child who believes in The Seed Fairy. ” — Robert Breault
by Lucia Eilers

Best Practices for Fighting Weeds – 8/1/2014

Weeds are diligent and determined, thus seed production is amazing. An annual bluegrass plant can produce viable seed within 24 hours of pollination. Have you ever cut a Salsify, those giant “dandelions puffs”? If you do not discard the plant, its severed head filled with merely flower buds, will skip the flower stage and immediately produce a large seed puff.

Area residents are asking master gardeners questions about eradication of rogue violets, mare’s tail, purslane, black medic, oxalis, and puncture vine. Have I mentioned your special nemesis yet?

In the spring, annual weed seeds germinate to grow madly to produce seed before they dry out in August.

Biennials started as a little cluster of leaves last summer, and this year an extended bloom stalk has grown. (Think of knapweeds and mullein.)

Perennials are those plants that have evolved massive root systems often with thick rhizomes deeply underground. You can kill the vegetation, and it will grow back almost before your very eyes. (Think of field bindweed/wild morning glory and horsetail.) These weeds are in your garden now; their seed producing capacity is awe-inspiring. Not only do the plants produce hundreds of thousands of seeds, the seed can remain dormant in the soil for years, and every time you distribute the soil by digging it, you expose more seeds to the light. Moreover, tricky plants such as violets can produce seeds underground without the benefit of flowers. In addition, oxalis and violets spread by underground stems.

Anyway, herbicides are not very effective on plants with narrow, hairy or waxy leaves. Annuals can be mown before they bloom — it is probably too late for that this year as well. If you cut or mow weeds and let the flowers lie on the ground, the decapitated plant can still produce seed that will haunt you for years to come.

For biennials you can just cut off the flowering stalk because the rest of the plant will die by fall anyway. This is best; if you pull the plant, you will disturb the soil, and any latent seeds will germinate to form a leaf roseate, which will set seed next year.

Don’t let the perennials bloom. And treat the plant with herbicide in the spring and fall. It is too hot now to apply herbicides. The Master Gardeners can tell you which products are most effective to use on any perennial weed.

What do you do with those weedy, seedy plants once you have cut them or pulled them? DO NOT compost them. DO NOT just leave them on the ground. Gather all the cut materials—seeds, flowers and stalks, and put them in a large plastic bag that can be sealed. Put the bag in the trash.

Or after you have filled the bag with the weedy material, add two cups of water, seal the bag and place it in a very hot and sunny spot. With the summer’s heat, the seed material will boil and be rotted in the bag. After a couple of weeks of heat treatment, this slurry can be added safely to your compost pile. There should be no recognizable plant parts in the smelly slurry.

A final word. After you have eradicated the weeds, apply at least a 3-inch layer of mulch over the bare soil to prevent new seeds from germinating and to slow down next year’s crop.
by Bonnie Orr

How to Control Puncture Vine – 6/1/2015

Puncture vine, also called goat head, is a painful weed because of its hard, spiny seeds. The plant’s botanical name is Tribulusterrestris; tribulus means “to tear” in Latin. The seed can tear open people’s feet and cause annoying punctures in bicycle tires and inflated balls. Have you ever stepped on one that got walked onto the carpet of your house because the seed hitched a ride on the bottom of a running shoe? The seeds can damage animals’ mouths, feet, eyes and digestive systems. This plant originated in the Mediterranean and was distributed across the Western U.S. by livestock, shipped hay, and the wheels of railroad cars. Having been seen in Washington since 1923, it is high time we got rid of this noxious weed in NCW.

The plant is an annual. The seeds sprout in sandy, dry soil beginning in May and form a flat rosette of leaves from which long branches grow. These branches produce yellow flowers that each produce a seedpod that contains up to 4 seeds. A single plant can produce hundreds and thousands of seeds. The record producer grew in California with 576,000 seedpods — and if each pod had 4 seeds that means that the one plant could produce over a million seeds! Ouch!

If everyone would pull these plants, which are just now blooming and setting seed, we could begin the process of knocking back this weed. It is important to pick up any seeds lying on the ground as well because the seeds can sprout for up to nine years in the ground.
Most of the plants grow on dry soil along roads and trails—anywhere the soil is disturbed by people or dogs walking along. The seeds need light to germinate, and the scuffing of the soil is one of the ways the seeds are brought to light. One means of slowing the spread of puncture vine is to stay on trails and paths.

It is easy to pull the plants up. You roll all the branches together to the center of the plant and then give the entire plant a twist. The entire root should come up with the plant. If using a claw hammer, wrap the claw in the center of the plant, twist, and the plant will pop out of the soil. It is not overly important to get the entire root since this plant is an annual and the root will die without its leaves. Be sure to gather up any little seeds that you knocked off as you gathered the plant. Some people use paint rollers; others find that carpet samples help pick up the seed.

1. Wear gloves and carry a heavy plastic bag that will not break and inadvertently distribute the seeds.

2. Look for the plants around your neighborhood. Great locations are under mail boxes on postal driving routes because the seeds get caught in vehicle tires. Look in alleys as well because the garbage truck’s tires also spread the seeds. Check the sides of parking lots.

3. Go out on the Apple Capital Loop Trail, especially on the eastside, and gather as much as you can.

Walk along roads that have gravel edges and pull up the plants.
Dig any rosettes, — little plants — that you see. Puncture vine seeds germinate every time it rains during the summer. So inspect your cleaned target areas all summer long for new plants.
by Bonnie Orr

How to ID and Fight Thistles and Knapweeds – 7/1/2016

This time of year weeds often take front and center as we struggle to keep them from overtaking our garden beds and lawns. However, not all weeds are the same in terms of their threat to our gardens, pastures, cultivated fields, and native ecosystems. Interestingly, almost half of our noxious weeds are “escapees” from gardens!

In this article we will focus on two sets of weeds that are on the Washington State Noxious Weed Control Board’s noxious weed list: the knapweeds and thistles.

Two species of thistle are commonly found in the Wenatchee Valley: bull thistle (Cirsium vulgare) and Canada thistle (Cirsium arvense). As Class C weeds, they are widespread throughout Washington. Bull thistle is the larger of the two, growing from 3 to 7 feet tall. It is a biennial with only one upright branched stem. It spreads through seeds. Canada thistle is a perennial that grows up to 5 feet tall and has slender grooved stems that branch only at the top. The leaves of both plants are alternate, but the bull thistle leaf is coarsely lobed, while the Canada thistle leaf is lance shaped. Bull thistle flowerheads are larger than the Canada thistle’s, 1.5-2” in diameter vs. ½ to ¾”. Both have purple flowers, but the Canada thistle’s can also be pink and occasionally white. Bull thistle blooms July through September. Canada thistle has a longer flowering season – June through October.

Bull thistle can be controlled by rototilling or hoeing/hand-pulling. Because Canada thistle is a perennial with an extensive root system, cultivation is not recommended. Instead, you can cover the infested area with an inorganic mulch, then cover the mulch with a thin layer of soil or organic mulch. Glyphosate can be used for both species as a spot treatment only. See Hortsense for other chemical management options.

Knapweeds are another noxious weed common in our area. Most are Class B weeds, meaning they are widespread in some parts of the state. The Bighead, however, is Class A, a relative newcomer that hasn’t yet gained a firm foothold in our region. Landowners have a legal responsibility to eradicate Class A weeds from their property.

Of the knapweeds on the noxious weed list, five are perennials: Bighead, Black, Meadow, Russian, and Brown. Diffuse and Yellow Starthistle knapweeds are annuals, while the Spotted knapweed is a biennial. Each has a taproot, ranging from woody to fleshy, except Russian knapweed which has a horizontal root system. Leaves of the Bighead, Black, Meadow, and Brown knapweeds have lance-shaped leaves. The lower leaves of the Diffuse are divided with narrow and elliptical upper leaves; Russian knapweed lower leaves are long and lobed with smaller toothed upper leaves. Young Spotted knapweed leaves are deeply lobed, turning to elliptical with age. Yellow Starthistle lower leaves are deeply lobed as well, with smaller, pointed upper leaves. Most of these knapweed species have rose, pink, or purple flowers. The Bighead and Yellow Starthistle have yellow flowers. Diffuse and Spotted can have white flowers.

Telling knapweeds apart can be difficult, but management is similar for all of them. According to the Noxious Weed Board, finding and controlling the knapweeds early is key to preventing an infestation. The most effective control is done through a combination of mechanical, chemical, cultural, and biological controls. Cultivation through rototilling or hoeing/hand pulling will reduce the population. As with the thistles, use glyphosate products as spot treatment only. Consult Hortsense for other chemical options.

(The Noxious Weed Board’s website is an excellent resource and the one I used for writing this article. Some of their educational materials are available on the table outside the conference room at the WSU Extension office on Washington Street. I also used information from Hortsense.)
by Casey Leigh

Virginia Creeper: Plants Gone Wild – 8/1/2022

In a recent clinic meeting, we discussed a somewhat desperate e-mail from a client who was seeking advice about removing a large, unidentified plant in her yard that had given her a rash. Her photos revealed a lush (and yes, expansive) hop plant. This led us to a bigger question: what are some plants that serve a good purpose but can quickly grow out of control?

Hops (Humulus lupulus L.) are an excellent first example. Though our client had an unfortunate experience with them, they can be used medicinally, ornamentally, as a supplement in livestock feed, and even as a preservative, according to OSU Extension. And, of course, hops are probably best known for the role they play in brewing beer. However, they can be difficult to control given that they are rhizomatous. Left to themselves, the bines (stems) usually grow up to 15 to 20 feet (sometimes higher), not to mention their ability to spread out along the ground.

Virginia Creeper (Parthenocissus quinquefolia), a member of the grape family, is another example of a plant that can become “too much of a good thing.” According to Susan Mahr with the University of Wisconsin-Madison, Virginia Creeper can cover trellises and chain link fences, help with erosion control, and provide food with its berries for songbirds and other wildlife during the winter. However, much like a hop plant, it can quickly become a problem in a garden. It grows with extraordinary speed (up to 20 feet in a year!), and Mahr warns that it can stifle other plants, particularly in a small garden. Additionally, the berries it produces are moderately toxic to many mammals (including humans) due to their dense concentration of oxalic acid.

It’s also worth mentioning that there is a False Virginia Creeper (Parthenocissus vitacea), which is on the Washington State Noxious Weed Control Board’s monitor list. Its leaves look very similar to Parthenocissus quinquefolia, so you’ll have to look closely to tell the two plants apart. For example, True Virginia Creeper leaves are a more muted green color; additionally, there are hairs on the underside of the leaves and on the veins. False Virginia Creeper leaves, by contrast, have no hair and are a vibrant green. However, the most helpful things to look at are the plants’ tendrils. True Virginia Creeper has tendrils that terminate in small, sticky discs, which allow the plant to latch onto things. While False Virginia Creeper also has tendrils, they divide into fewer branches than a True Virginia Creeper’s and they don’t have any discs.
By Jacqueline Sykes

Weeds in May – 5/1/2017

One of the most common questions in the clinic in May is how to get rid of weeds. People want to know what to spray — what is an easy way to get rid of weeds? Many people are sure that the weeds are coming in the irrigation water.

The real question should have been,“ How can I prevent weeds from over-running my garden, flowerbed, etc.?”

Prevent weeds such as purslane, oxalis and spotted spurge by rubbing them out with a hoe when they first appear and before they go to seed. These weeds mostly occur on road verges and on the edges of flowerbeds and lawns — that is until they truly get established. There is a pre-emergent designed for this evil trio, but it is not registered for use in Washington State.

In late July we will start getting questions about crabgrass because people have missed the window to apply pre-emergents. It has been hard to judge this year because of the cool soil and late spring. On April 6th my Forsythia sprang into bloom about two weeks later than normal and nearly four weeks later than last year. We suggest watching for Forsythia bloom because that indicates the soil is 50 degrees. Dandelions bloom at 55 degrees — and that is when crabgrass seed germinates as well.

Needless to say, noxious weeds must be eliminated before they flower.

Weed seed arrives during our windy springs and during the late summer winds. It loves to land on deep compost or nestle between rock mulch sitting on wind-blown soil collected weed barrier fabric. If an irrigation system, especially drip or mister systems, has effective filters, weed seeds cannot arrive via irrigation water. I have never found weed seeds in my filter. I once washed out the filter at the end of June, dried the residue, and did not find even fine seeds.

We suggest that gardeners weed well in early spring.

The solution to weeds is mulch, mulch, mulch. Weed seeds need light to germinate. I weed my flowerbeds once in early spring, mulch, and never weed again all season.
In the clinic we try to convince people of the power of 3-4 inches of mulch that will pretty much ease their problems with weeds. Of course, many people come to us when the oxalis has totally covered a flower bed and violets have filled up the lawn. Then we ask them to live with it because many weeds once they are established are next to impossible to eliminate without totally tearing out the landscape.
By Bonnie Orr