How to overwinter your dahlia plants

Posted11/3/2019 6:00 AM

Q: What should be done with dahlias before the winter weather arrives?

A: When I first saw this question, I was kind of bummed. Most years I plant dahlias but this year I did not and I missed their bright colorful display in my garden. In the Midwest, we consider dahlias to be tender perennials, meaning they won't survive our sometimes harsh cold winters if left outdoors.


The great news is you can overwinter dahlias with just a bit of effort and celebrate their beauty come spring. As fall moves in and the first frost arrives, you'll notice that your dahlia leaves will blacken. That means it's time to dig up your dahlia tubers and bring them inside.

Start by cutting off most of the stem leaving about 2 to 4 inches of growth. Being gentle with your shovel, dig up your tubers without damaging them. Shake the dirt from the tuber clumps and allow each to dry out for a few days in a cool location protected from frost.

After having dried them, you can shake off any remaining loose soil, cut the stems back to 1 to 2 inches and prepare them for winter storage. There are several options for storage.

Some gardeners fill a ventilated box with some lightly moistened sand, peat moss or vermiculite and put their tuber clumps among the filler to protect them for the winter. Some use a brown paper bag, adding a similar medium like peat moss or vermiculite or even shredded paper. Whichever method you choose, be sure you keep the tubers stored in a cool location. I've stored mine in my basement laundry room, which stays cooler than the rest of my home during the winter.

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You should be sure to check on your tubers throughout winter for any rotting or drying out. If your tubers look to be shriveling, mist them lightly with water. If you notice any rot, trim the rotted portion of the clump off.

Note: If you happen to plant your dahlias each spring in a container, no need to dig them up. Just trim your dahlias back to about 2 inches and bring in the container after the first frost. Be sure to store it in a cool, dry place as well. If you also love cannas, you can use this same approach to store them for winter.

As spring approaches and the last frost moves on, take your tubers and plant them in your yard once again for another year of beautiful bright flowers.

-- Wendy Reiner

• Provided through the Master Gardener Answer Desk, Friendship Park Conservatory, Des Plaines, and University of Illinois Extension, North Cook Branch Office, Arlington Heights. Call (847) 298-3502 on Wednesdays or email Visit

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