{"id":24998,"date":"2025-09-13T05:05:00","date_gmt":"2025-09-13T12:05:00","guid":{"rendered":"https:\/\/extension.wsu.edu\/yakima\/?p=24998"},"modified":"2025-09-23T10:18:08","modified_gmt":"2025-09-23T17:18:08","slug":"dahlias-in-the-fall","status":"publish","type":"post","link":"https:\/\/extension.wsu.edu\/yakima\/2025\/09\/13\/dahlias-in-the-fall\/","title":{"rendered":"Dahlias in the Fall"},"content":{"rendered":"\n

Dahlias in the Fall<\/strong><\/h1>\n\n\n\n


by Carol Barany, Yakima County Master Gardener<\/strong><\/h2>\n\n\n\n

I\u2019m at my desk writing because it\u2019s too hot to work outside.  By the end of today, September 3, Yakima could break the all-time high temperature record.  I\u2019m trying to leverage that with the fact that the average first frost date recorded at the airport in my 98902 zip code is October 3. <\/p>\n\n\n\n

Two weeks later on October 15, the City of Yakima will end its irrigation season, another milestone on the march to the end. <\/p>\n\n\n\n

My dahlias must have heard the news.  They\u2019re blooming with wild abandon, holding nothing back just when other flowers are slowing down.<\/p>\n\n\n\n

When gardeners get together these days to compare notes, I\u2019m amazed by how many of them are growing dahlias.  <\/p>\n\n\n\n

It hasn\u2019t always been easy for these dramatic divas.  Ignored for years by sophisticated gardeners, dahlias were considered old-fashioned and even gaudy not that long ago. These days, dahlias are enjoying a run as the \u2018It\u2019 flower. <\/p>\n\n\n

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\"Floral<\/figure><\/div>\n\n\n

Posting stunning photos of voluptuous dahlias as wedding flowers in her books and magazines beginning in the 1990s, many credit Martha Stewart for turning the tide.  A few years later in 2008, Erin Benzakein of Washington\u2019s Skagit Valley founded Floret Flowers.   Erin is considered by many to be the United States\u2019 most influential flower farmer.  Together, both women revived an interest in not just dahlias but locally sourced, fresh seasonal flowers. <\/p>\n\n\n\n

New small-scale cut-flower farmers shared their stories and photos.  All those gorgeous images of dahlias on Instagram and Pinterest captured our attention and inspired home gardeners to grow some dahlias of our own. <\/p>\n\n\n\n

Just as \u2018tulipmania\u2019 gripped Europe in the 17th<\/sup> century, these days, it\u2019s \u2018dahliamania.\u2019  <\/p>\n\n\n\n

Most September days begin for me at dawn with a cup of coffee and a pair of snips. In the still-cool hours of the morning, it\u2019s a pleasure to cut a bucket of blooms for bouquets.  <\/p>\n\n\n\n

The honeymoon will be over come November, when the real work begins.  Digging, dividing, and storing tubers\u2026..not my favorite tasks. But for now, I\u2019m madly in love and don\u2019t mind the maintenance tasks. <\/p>\n\n\n\n

I\u2019ve learned from my friend Nancy that stripping the plant\u2019s lower leaves up to about 16\u201d from the ground can improve air circulation and keep late-season powdery mildew at bay.  Many of these leaves are brown or declining anyway, contributing nothing to photosynthesis, so why not get rid of them now?  <\/p>\n\n\n\n

If you\u2019ve been fertilizing your dahlias regularly, it\u2019s recommended that you stop 30 days before you dig your tubers.  The plant should be focusing its energy on tuber production, not growing more leaves and blooms.  <\/p>\n\n\n\n

Once dahlia plants are cut down by frost, they all look the same.  Imagine a collapsed heap of mushy stems.  If it\u2019s important for you to know one dahlia from another next spring, check their ID tags now for accuracy.  <\/p>\n\n\n\n

While my dahlias are still blooming, I\u2019ll tie a length of plastic flagging tape to the base of each clump.  With a permanent marker, I record the variety name. Some of the flags will be marked \u2018LOSER,\u2019 reminding me which dahlias are not worth growing again next year.  When I dig the clumps for storage, they\u2019ll already have an ID label attached that can go into storage with them.<\/p>\n\n\n\n

For as long as I\u2019ve grown dahlias, I\u2019ve waited a week or two after a killing frost to dig the tubers.  I recently discovered it\u2019s a myth that frost is necessary for successful winter storage. Gardeners in warm or tropical climates that never get frost dig and divide their dahlias just fine.  <\/p>\n\n\n\n

That\u2019s because as the days grow shorter at the summer solstice, increasingly longer nights trigger dahlias into tuber development.  According to dahlia expert Kristine Albrecht, you can dig tubers after they\u2019ve been growing for a minimum of 135 days.  There is nothing wrong with waiting for frost, but it\u2019s not a requirement.<\/p>\n\n\n\n

Dahlias can be left in the ground to overwinter in USDA Zones 8 and warmer. In colder climates, dahlia clumps must be lifted and stored indoors to prevent them from freezing.  <\/p>\n\n\n\n

Are you a gardener who likes to walk on the wild side?  Some Zone 7 Yakima gardeners successfully leave their dahlias to overwinter right out there in their garden beds with some extra protection.   <\/p>\n\n\n\n

I still cling to the ritual of digging and storing my tubers every November.  As soon as they\u2019re dug and stored in the basement, I cover the beds with about 12\u201d of shredded leaves to protect the soil.<\/p>\n\n\n\n

Last year, I left several \u2018LOSER\u2019 clumps I never wanted to see again in place and said \u201cgoodbye.\u201d  Guess what?  This spring, as I cleared away the leaf mulch to plant a new crop of dahlias, virtually every one of those \u2018LOSER\u2019 clumps was alive and sprouting.<\/p>\n\n\n\n

For great information on dahlia culture, consult the American Dahlia Society website: www.dahlia.org.<\/a><\/p>\n\n\n\n

Kristine Albrecht has her own YouTube channel with more excellent advice and information. <\/p>\n\n\n\n

If you\u2019ve never grown dahlias before, these resources may convince you to give it a try. <\/p>\n\n