A Stroll Through the Garden: Preserving the magic of dahlias

Eric Larson
·4 min read

This week I heard from a reader and a client of mine who enjoys the patio that we made for him a few years ago. One of the new beds has been blessed with a number of new dahlias. He has reached the point where he wants to over-winter the tuberous roots and wants to know the best way to preserve them for next year.

When I first got started in landscaping, I had an internship at Schoepfle Gardens in Birmingham, where I worked for a season. Joel, my supervisor, was tough but fair, and I do remember at the end of the season bringing all of the dahlia tubers out of one of the beds in the garden. The soil from which I removed the dahlias was rich and black, which happens to be the favorite soil of dahlias.

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An interesting fact about dahlias is they are a member of the aster family because of the bloom, I’m sure.

One of my other favorite memories about dahlias is the Dahlia Society displaying some of its beautiful flowers at Seacrest Arboretum. What I remember is walking through the garden and seeing all of these beautiful flowers with single blooms and umbrellas covering the flowers one hot summer afternoon.

You could see this huge yard with small umbrellas all over the yard covering the dahlia blooms. I thought it was kind of odd. What I did enjoy was the magnificent flowers; what a blessing seeing the incredible flowers.

Dahlia can be brought in and kept through winter as tubers. Keep in a cool place, not too moist or too dry.
Dahlia can be brought in and kept through winter as tubers. Keep in a cool place, not too moist or too dry.

Caring for dahlias over the winter

What I do remember about preserving the dahlias is that after the first frost has blackened the foliage, which should happen soon, you cut off the stems about six inches above the ground and discard the top half. I have also read you should get your dahlia out of the ground before the frost.

Frankly I can’t imagine you should leave the dahlia in the ground much longer than what we have after the temps start to dip below 32 degrees. You really do have to take extra care with these tuberous roots and gently fork out the tubers being careful to remove most of the soil and any broken roots. When you damage the tuberous roots, you have an excellent place for a disease to catch.

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Before you store your dahlia roots you are going to want to dry them out, so you want to stand the tuber upside down for about a week to drain off the excess moisture. At Schoepfle Gardens there was a root cellar under Otto’s house. Seriously, I just don’t remember using soil or anything else to store them. Conditions inside the root cellar were ideal for the dahlias to do well.

One of the trials is dahlia tubers can dry out if stored improperly. Therefore, you should think about storing them in say a peat muck soil that’s not super moist or moist vermiculite to reduce the chances for a disease to catch. You really should not completely cover the boxes as you are storing the dahlia. Crowns cannot be covered if the dahlia is to survive.

Temperature is important for dahlia storage

One of the keys to dahlia storage is you need to store dahlias in a temperature range from 30-50 degrees. As I said previously, we are in ideal conditions to grow all kinds of fungi that can be harmful if the dahlia is damage.

I wish you all luck in trying to preserve your dahlias. There is the potential that you could be enjoying these same plants for many years to come.

Hope you have a nice stroll through your garden this week and accomplish the goals that you have set out for yourself. You can send me an e-mail at ericlarson546@yahoo.com. Soon I shall start the blog back up and link it to the website at ohiohealthyfoodcooperative.org. I shall do the best I can to help you. Thank you all for your excellent questions.

Eric Lawson of Jeromesville is a veteran landscaper and gardening enthusiast and a founding board member of the Ohio Chapter of Association of Professional Landscape Designers.           

This article originally appeared on Mansfield News Journal: A Stroll Through The Garden: Preserving dahlias during the winter