Three tips on overwintering perennials in containers

Hosta 'Sum of All'
You can grow perennials, including hostas, in pots. This one is ‘Sum of All’ at the Hidden Gardens of Eden, home of Marcia and David Sully.

by Connie Oswald Stofko

It’s time to think about some simple steps to overwinter your plant.

These tips should work with any kind of perennial that is winter hardy; that is, any perennial that would come back in spring if it was planted in a garden bed over the winter.

Bonus tip: Before we get into that, let me say that I was impressed by this stunning hosta at the home of Marcia and David Sully in Eden. I’ve written a lot about container gardening before — apple trees in containers, perennials in containers, vegetables mixed with herbs and flowers and lots more. Yet I never considered growing a hosta in a container until I saw this one.

It’s just one hosta plant, but it grabs your attention. Called ‘Sum of All’, it has large, beautifully textured leaves with attractive coloration.

If you have a shady area where it’s hard to plant anything because of tree roots, choose a hosta (there are so many different varieties!), plant it in a pot and enjoy it throughout the growing season.

And if you want to enjoy it again next year, read on!

Tip the pot on its side

I had a pot in the winter that had standing water on top that was a couple inches deep. The pot was heavy and stuck to the frozen ground, so I couldn’t tip it over to drain off the water.

What I should have done was tip the pot on its side before that happened.

That standing water can create crown rot, said Marcia Sully, president of the Great Lakes Region Hosta Society and recording secretary of the American Hosta Society and of the WNY Hosta Society.

That standing water accumulates because of our freeze-thaw cycle, she explained. When it’s cold out, the soil in your container freezes. The weather warms up a bit, rain falls, but the soil in that pot might still be frozen three-quarters of the way down. The water can’t drain and the rain accumulates on top. That standing water isn’t good for your plant.

Prevent that from happening by setting the pot on its side.

Sully will do this with more ordinary plants, but for her prized ‘Sum of All’, she puts the plant in an unheated garage.

Set the pot in an unheated garage

When the perennial is going dormant or has died back, set the pot in an unheated garage or similar space.

Don’t water it through the winter, but you can put a handful of snow on it occasionally. You might not even have to water it, Sully said.

Ceramic or plastic pots?

Ceramic pots will crack if you leave them outside, so make sure you bring them in. They should be fine in an unheated garage.

Or try this tip: In spring, Sully plants many of her hostas in plastic nursery pots, then sets the plastic pots into decorative ceramic pots for the summer.

In winter, she pulls the plastic pots out of their decorative ceramic containers. She leaves the hostas in their plastic pots outside, then stacks the ceramic pots inside.

If you have a lot of plants, this will take up less room in your garage.

See more photos from Sully’s garden here.

10 Comments on “Three tips on overwintering perennials in containers

  1. I do the same with many hostas in pots. Plastic nursery pots in decorative ceramic. A great solution for mini hosta that would just get lost in a planted bed. I also have little to no slug damage on the potted hostas.

  2. I wonder if a Japanese painted fern can be overwintered in a ceramic pot in a barn the same way???

  3. My sister-in-law gave me a hosta plant several years ago and I just put it in a pot and it’s been in there ever since. Summer in the garden and winter in the garage. The best part is that I can move it around the backyard with the rest of my potted plants for different visual effects.

  4. I’m another fan of hostas in pots! You can give them nice rich soil, not disturb tree roots from digging in the ground, and best of all it’s easier to split and share.

  5. As a renter I have switched to growing all my plants in containers. I was lucky to find several large plastic “tree” containers. They work great and keep my hostas confined. In the fall when the plants die back, I fill the containers with leaves. In the spring when the new growth pokes thru the leaves I remove the leaves. I have been doing this for 7 years now. Not scientific but I believe my Hostas sprout a little earlier than before I covered them. Also drainage holes are mandatory.

  6. Robin, I’m not familiar with Japanese painted ferns. If it would come back in a garden bed, it should come back in a pot in a barn. Give it a try and let us know how well it works!

  7. Eddie, it’s great to have plants you can move around. Sometimes you need to fill in a bare spot or add a contrasting color with foliage. Thanks for the tip!

  8. Matthew, thanks for the tip on leaves. They probably help protect the plant from fluctuations in weather. See more here.

    Yes, drainage holes are necessary. Unfortunately, even with drainage holes, if the bottom part of your soil is frozen, rain water on top of the pot might not be able to drain out. That happened to me.

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