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Gardening Tasks

Master Gardener Program
Erika Johnson, Program Coordinator
(564) 397-5738

By the Month
General Maintenance
Pest & Disease Control

By the Month


  • Check stored bulbs and dahlia tubers. Discard the soft or rotted ones. Sprinkling with water will plump up shriveled tubers.
  • Water overwintering geraniums and fuchsias just enough to keep them alive.
  • Spray cherry trees for bacterial canker. Apply dormant spray to apples and pears.
  • Apply a dormant spray of lime sulfur on roses.


  • When soil becomes workable, prepare vegetable gardens for planting.
  • Plant peas in well-drained soil.
  • Prune fruit trees when the temperature is above freezing.
  • On mild days, plant bare-root roses, berries, grapes, kiwis, and fruit trees.
  • Pull mulch partly away from emerging bulbs and perennials. In mid-month, hunt hidden slugs.
  • Start broccoli, cabbage and cauliflower indoors.


  • Prune and fertilize summer blooming clematis.
  • Divide perennials that will bloom after mid-June.
  • Trim heather and heaths after blooming, just back to below the point where blooms form.
  • Fertilize established roses when they begin to leaf out.
  • Bring over-wintering fuchsias and geraniums out of dormancy.  If needed, put fuchsias in larger pots with fresh soil. Check for circling or damaged roots.
  • Apply dormant spray on cane berries before or just after buds swell.
  • Spray peaches and nectarines with lime sulfur to control peach leaf curl.
  • Control slugs around newly planted seedlings.
  • Fertilize blueberries, blackberries and raspberries with 5-10-10 fertilizer.


  • Remove and destroy tent caterpillar larvae and nests.
  • Knock aphids off roses with a stream of water.
  • Set out transplants of hardy annuals such as primroses, dusty miller and pansies. Direct sow snapdragons, sweet alyssum, cornflower, clarkia, calendula, larkspur, and Shirley poppy.
  • Plant dahlias, ranunculus, gladiolus, iris and cannas.
  • Dispose of fallen camellia blossoms to control the spread of botrytis or petal blight.
  • Control brown rot on nectarines, apricots, peaches and cherries.
  • Control spittlebugs, aphids and slugs on strawberries.
  • Protect dogwood trees from anthracnose.
  • Use floating row covers to protect plants in the cabbage family from egg laying by cabbage root maggot flies.


  • Remove suckers from roses, lilacs, grafted ornamentals and fruit trees. Cut suckers off flush with roots.
  • Fertilize rhododendrons and azaleas. Remove faded blooms. Prune plants to control size.
  • Prune Euonymus and forsythia.


  • Fertilize lawns with a fertilizer containing a 3-1-2 or 6-1-4 ratio of N-K-P, applying 1 pound of nitrogen per 1000 square feet.
  • Divide spring blooming perennials after their flowers fade.
  • Sow fast growing annuals such as calendula, cleome, nasturtium, sunflower and zinnia.
  • Continue watering bulbs until the leaves start turning brown. You may remove leaves that pull away easily when you give a gentle tug.
  • If your apple trees are not scab resistance cultivars, continue to apply a registered fungicide until dry weather. After apple trees do their annual June drop, thin fruit so they are spaced 6 to 8 inches apart.
  • Spray cherry trees for brown rot.
  • Protect berries with bird netting.


  • Feed roses and other shallow rooted shrubs.
  • Prune or trim flowering shrubs.
  • Control coddling moth on apples.
  • Apply a band of sticky material — such as Tanglefoot — to the trunks of rhododendrons to keep weevils down.
  • Control Red Thread in lawns by maintaining an 
adequate fertilizer program and mowing regularly.
  • Fertilize asparagus and let it shoot up into foliage plumes.
  • Mulch rhubarb with compost.
  • Prevent or control late blight of tomato and potato.
  • Withhold water on onions and garlic as tops begin to dry.
  • Prune summer-bearing cane berries after harvest. On fall-bearing types, cut out summer fruiting canes after harvest.


  • Divide primroses, poppies, candytuft and daylilies.
  • Do not apply fertilizer to trees and shrubs. Decrease water on broad leaf evergreen shrubs.
  • Feed chrysanthemums lightly at two week intervals.
  • Deep water dahlias at ground level to sustain growth and reduce danger of mildew.
  • Spray for apple maggot, if needed. Continue control of codling moth on apples.
  • Prune fall webworm nests from ornamentals and destroy.
  • Fertilize June-bearing strawberries.


  • Feed lawns early this month with one pound of actual nitrogen per 1,000 square feet of turf using a 3-1-2 or 6-1-4 fertilizer. Remove thatch and aerate. Patch bare spots.
  • Dig and divide daffodils.
  • Plant cover crops, ground covers, shrubs and trees. Keep plants well watered until fall rains come.
  • Control coryneum blight and bacterial canker on peach and cherry trees with a registered copper spray.
  • Control cane and leaf spot on cane berries with a registered fixed copper spray.
  • Harvest potatoes after tops die down. Harvest Bartlett pears when they are green ripe.
  • Protect tomatoes if frost threatens, or harvest remaining tomatoes and ripen indoors.
  • After final harvest of fall-bearing raspberries, prune off top half of canes.


  • Water houseplants less frequently, and stop fertilizing.
  • Dig dahlias shortly after frost blackens their foliage. Dig gladiolus corms and cut leaves back an inch from the corm. Label, dry, and store.
  • Plant trees and shrubs before fall rains arrive.
  • Harvest sunflower heads, winter squash, pumpkins, and apples.
  • Divide rhubarb.
  • Use tree wrap to protect the trunks of young fruit trees from sun-scald and rodents through winter months.


  • Clean up flower beds. Pull out annuals; cut back herbaceous perennials to a few inches above the ground.
  • Prune roses to 2 1/2 feet. Remove leaves and mound 8 inches of mulch around canes.
  • Plant or move trees and shrubs now through early spring.
  • Collect and dispose of leaf and fallen fruit debris from under fruit trees. Many insects and disease organisms overwinter in such debris.
  • Cut back the oldest and least vigorous stems on blueberries to a young shoot or to ground level. Thin twiggy branch tips and remove any broken, dead or diseased branches.
  • Tie summer-bearing raspberry canes to wires and prune 6 inches above the top trellis wire. Cut off the tip sections of ever bearing raspberry canes that fruited this fall. For a fall-only crop, cut all canes to the ground.
  • Move container plants to a sheltered location.
  • Withhold fertilizer from houseplants from now until mid-March unless they are actively growing.


  • Remove foil or wrap from poinsettia pots. Keep plants in indirect sun light at 60-70° F, and away from heat sources. When soil is dry, water poinsettias at the sink and let them drain thoroughly. Don’t fertilize or mist (which could encourage the growth of fungus). Let faded bracts and leaves fall naturally, then dispose of them.
  • Spray peaches and nectarines with lime sulfur to control peach tree curl.
  • Water plants under eaves and in protected entries. Well-watered plants take freezing temperatures better than dry ones.
  • Apply aged compost to groomed beds and use it to mulch tender plants.
  • Turn compost, continue to add materials to it, and keep it covered during rainy periods.

General Maintenance

  • Compost disease-free clippings.
  • Keep compost pile moist to ensure speedy decomposition.
  • Pull weeds before they bloom and release seeds. Consider putting down a weed-inhibiting mat or mulch.
  • Continue to fertilize container plants through the blooming season. A fractional weekly dose is better than a full dose monthly.
  • Water new plantings more frequently.
  • Reduce moisture loss from evaporation by early morning deep watering.
  • Mulch shrubs and garden plants to protect them from hot weather damage.
  • Fall planting of new lawns is satisfactory from August through mid-October, however April and May are better times in this area. Adequate surface moisture must be maintained for germination and seedling growth.
  • Maintain tools – clean, oil, and sharpen them.
  • Rebuild soil by adding organic matter. This will loosen clay soils and help sandy soils hold water and plant nutrients.
  • Clean greenhouses thoroughly. Make sure vents, heaters, and irrigation systems are in working order.


  • Feed roses and other shallow-rooted shrubs.
  • Check for blackspot on roses. Control with a registered fungicide and avoid overhead watering, which aids in spread of the disease. See the July 2002 article, Black Spot.
  • Divide overcrowded bearded iris rhizomes after they bloom. See Dividing Bearded Irises from the August 1999 issue.
  • Divide crowded narcissus bulbs after foliage dies back. Use a spading fork to gently lift bulbs, brush or shake dirt from the clumps and let dry for several days in a cool, dry, shaded spot before replanting.
  • Propagate camellias by ground layering.
  • Mow lawns, taking off no more than one-third of blade length at a cutting. This favors healthy, deeply rooted turf that crowds out weeds.
  • Prune or trim flowering shrubs such as azaleas and heather, after flowers fade.Divide early spring bloomers such as primroses, poppies, candytuft, and daylilies.
  • Starting in August, do not apply fertilizer to trees and shrubs. Decrease water on broad-leaf evergreen shrubs; it’s time to harden them for winter.
  • Feed chrysanthemums lightly at two-week intervals. Lack of water may result in fewer flowers.
  • Deep water dahlias at ground level to sustain their vigorous summer growth and reduce the danger of mildew.Deadhead flowering plants to prevent reseeding and prolong bloom time.
  • Sow wildflower seeds for garden color next spring.
  • Tend Lawns. Feed early in September with one pound of actual nitrogen per 1,000 square feet of turf using a fertilizer with a 3-1-2 or 6-1-4 ratio of Nitrogen, Phosphorus, and Potassium. Remove thatch and aerate. If lawn has bare spots, rake to loosen soil, remove fallen leaves, eliminate weeds, sow new grass seed, cover seed with a light layer of new soil, and water it in well. See EB0482, Home Lawns.
  • Dig gladiolus corms as soon as leaves start to turn brown. Cut off leaves about an inch from the corm. Dry corms in a warm place out of direct sun, then store in a cool, dark, and dry place.
  • Purchase spring blooming bulbs – daffodils, tulips, hyacinths, crocus – to be planted late next month. Shop early to get the best selection and store in a cool dry place.
  • Dig and divide perennials.
  • Plant ground covers, shrubs, and trees. Keep plants well watered until fall rains come.


  • Harvest herbs just before flowering and early in the day for best flavor.
  • Fertilize and retire asparagus. Let them shoot up into plumes of foliage.
  • Plant vegetables such as beets, bush beans, mustard, radishes, Swiss chard, and turnips.
  • Take steps to prevent or control late blight of tomato and potato. See the July 2004 feature article Healthy Tomatoes
  • Prune summer-bearing cane berries after harvest. Cut back canes that bore fruit clear to the ground. On fall-bearing types, like Heritage, cut out summer fruiting canes after harvest. After fall harvest, cut off top half of all remaining canes. These will bear a summer crop the following June. On both types, remove any weak or damaged canes. See EB1640, Growing Small Fruits for the Home Garden, for further information on raising berries.
  • Plant seeds of arugula, overwintering onions, turnips, mustard greens, and Brussels sprouts in August. Spring cabbage planted now is ready to harvest in March and April. See Sow in August – and Harvest Fall, Winter, and Spring.
  • Provide cabbages with 1 to 1 1/2 inches of water per week. Over-mature heads are subject to splitting, especially if exposed to moisture fluctuations. Cabbages with mature, firm heads can be given a quarter turn twist to break part of the roots and retard growth. This will help prevent splitting.
  • Harvest pole beans from the ground up – those closest to the ground ripen first.
  • Add nutrients to the soil and prevent soil erosion by planting cover crops such as winter rye, vetch, crimson clover, and Austrian field peas. For more information on vetch, see our August 2000 article, Vetting Vetch.
  • Fertilize June bearing strawberries in late summer to promote fall growth and flower bud initiation for the following season’s crop. Use 1 pound of 10-20-20 or 2 pounds of 5-10-10 per 100 sq. ft.
  • In September, sow seeds of scallions, spring cabbages, and other winter-hardy vegetables. See the September 2001 feature article, Edibles to Plant during September.
  • Harvest potatoes after tops die down. Store in a dark location.
  • Protect tomatoes if frost threatens, or harvest remaining tomatoes and ripen indoors.
  • Harvest Bartlett pears when they are green-ripe. Lift a pear up and outward, putting moderate pressure on the stem where it joins the spur; if the stem breaks free from the spur, the pear is ready to pick. Anjou pears are ready about one month later than Bartlett.
  • After final harvest of fall-bearing raspberries, prune off top half of canes.
  • Keep crops harvested as they mature. Mound soil around leeks.

Pest and Disease Control

  • Control codling moth on apples. See EB0419, 2013 Crop Protection Guide for Tree Fruits in Washington.
  • Apply a band of sticky material, such as Tanglefoot, to the trunks of rhododendrons to keep weevils down. Some rhododendron species are resistant to feeding by root weevil adults. Extension Bulletin 0970, Root Weevil Control on Rhododendrons, lists resistant species and describes biological, chemical, mechanical, and cultural controls.
  • Spray for apple maggot, if needed. EB1928, Protecting Backyard Apple Trees from Apple Maggot, describes apple maggots, their life cycle, and control.
  • Prune fall webworm nests from ornamentals and destroy.
  • Consult EB1552, Scale Insects on Ornamentals for life cycle and control information on scale.
  • Control corn earworm on early corn. See EM0009, Pest Control in Home Garden Vegetables for corrective non-chemical control methods or call the county Extension office for a list of recommended registered insecticides.
  • To control coryneum blight and bacterial canker on peach and cherry trees, spray with a registered copper spray after harvest and prior to heavy rain. For complete spray program, see EB0419, 2013 Crop Protection Guide for Tree Fruits in Washington.
  • To control cane and leaf spot, spray caneberries, excluding raspberry, with a registered fixed copper spray after old canes have been removed, and before fall rains begin. EB1015, Insect and Disease Control for Home Gardens, Small Fruit Crops, provides schedules for caneberries, grapes, blueberries, strawberries, and other small fruits.

Garden Mastery Tips is brought to you by the Clark County Master Gardener Web Publishing Team – S. Bjordahl, E. Chase, S. Greenlee, F. Hammond, T. Koskinen, A. Beesing-Sparks, and M. Stauffer.

Warning. Use pesticides with care. Apply them only to plants, animals, or sites listed on the label. When mixing and applying pesticides, follow all label precautions to protect yourself and others around you. It is a violation of the law to disregard label directions. If pesticides are spilled on skin or clothing, remove clothing and wash skin thoroughly. Store pesticides in their original containers and keep them out of the reach of children, pets, and livestock.

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WSU Clark County Master Gardener Program
1919 NE 78th Street • Vancouver, WA 98665
(564) 397-5738

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