My Wintering Over Experiments

– Posted in: Experiments, Garden chores, How-to

If you’re going to grow as a gardener, you have to experiment, you need to try new things. It may be a plant you’ve never grown, or how-to advice you’re going to tinker with to make your own. Because gardening advice is necessarily one-size-fits all, and your garden has very specific conditions. That’s how you get to be an experienced gardener, by trying–and sometimes failing–and trying again until you’re happy with the results (or decide it’s not worth the bother). Once you figure out what works for you, it kind of turns into tradition, and you’ll find yourself telling less experienced gardeners that you’ve always done it this way.

I’m wintering over many plants I’ve never wintered over before. I’ve successfully brought dahlias, cannas, gladiola, tuberous begonia and Mirabilis longiflora (a relative of four o’clocks) through the winter in other years. This year I made several impulse purchases which I justified by telling myself I would winter them over. And reading this article on the Proven Winners website made me realize there were other plants I could winter over. Also, I wanted to preserve some of the plants from the gorgeous hanging baskets I received for my birthday this year. That adds up to more than a dozen experiments.

birthday hanging basket

I got two of these gorgeous hanging baskets for my birthday, and I’m attempting to carry the geraniums and the sweet potato vines through the winter. If they survive, I will probably use them in window boxes on the carriage barn.

I’m not sure this is going to work, but how do I know unless I try? My wintering over experiments fall into two categories: dormant plants that I hope to bring out of dormancy next spring, and plants that I’m growing as houseplants that will be returned outdoors in the spring. For a few plants, I’m trying them both ways. In the case of the houseplants, I will be happy if they merely survive well enough for me to take cuttings in the spring or to cut them back and induce new, healthy growth. I fully expect them to get leggy and bedraggled with the lower levels of light in my house.

What I did and why

Here’s what I’ve done, plant by plant, in roughly alphabetical order. I hope it inspires you to do some experimenting of your own!

Agapanthus (aka Lily of the Nile) A friend had recommended the Storm series to me: ‘Snow Storm’, ‘Blue Storm’, ‘Thunder Storm’, and ‘Sea Storm’. That’s what I thought I was getting when I ordered ‘Storm Cloud,’ but I didn’t go back and check the email and later found out I was wrong. However, it’s a deep bluish-purple, which is what I was looking for, so onward with the experiment! I received a pretty small plant in the mail, and it didn’t bloom this year. My goal this summer was to enable it to build up size and strength so that it would bloom next year.

Turns out there are deciduous and evergreen agapanthus and you winter them over differently. After some detective work, I determined mine was evergreen, so it came out of the big container on my terrace and into a small container of its own, and is now part of my houseplant collection in the dining room. Our dining room is where our woodstove is located, so it’s the warmest room in the house. We also have a big east-facing window that’s not overhung with a porch roof in this room, so it gets the most light of any window that’s in a warm room.

houseplants in dining room window

The large dining room window gets morning sun–assuming the sun is shining, which is a rare thing. The terra-cotta-looking plastic pot at far left holds the tropical hibiscus. At bottom right you can just see one of the Lemon Coral sedums. The big orange tree belongs to my son. He grew it from a sprouted seed he found in an orange many years ago.

Angelonia I learned from Hot Plants for Cool Climates by Susan Roth and Dennis Schrader that angelonia can be overwintered as a dormant plant. My two angelonias were in a container with other plants, so I dug them out of there, cut the stems back to ground level and repotted them. They are stored dry in the basement.

Begonia I bought tuberous begonias for the Garden Shelter. They seem well-suited for that location, but they were expensive, so I want to winter them over. I have had mixed success wintering them over in past years. I kept one going for two or three years and then one year it just didn’t resprout. Fingers crossed for these Mistral Pink begonias. I’m following the advice on A Way to Garden and keeping them in their hanging baskets.

wicker hanging baskets in the garden shelter

The garden shelter sported two of these hanging baskets growing tuberous begonias.

Canna As I mentioned, I’ve wintered over cannas before. I used to have several different kinds, and they all made more tubers and there was more to take care of every year. I decided I didn’t need that many cannas, so now I just winter over Tropicanna Gold. I dig them up, shake off as much dirt as I can, and put them in a plastic garbage bag, again following advice on A Way to Garden. Cannas don’t do that well for me. They don’t get that big and often don’t flower. Maybe they don’t get enough heat, and maybe they don’t get as rich a soil as they’d like. They still work well enough in containers as a foil for other plants, so I’m keeping them going.

Coleus (Solenostemon varieties) I bet more people overwinter this tender perennial than any other, because it’s so easy. Cut some stems, stick them in a glass of water, and watch them root. I think it’s best to pot them up soon after, but I confess I haven’t done that yet with mine. I did root some cuttings in vermiculite as well, just to see if I could. I think they “took” and I need to pot them on in potting soil.

Dahlia I used to grow dahlias in pots because I knew I wanted to bring them into the basement for the winter. We had a dirt basement in our former home and one year a dahlia actually rooted into the floor! But dahlias grow bigger and better when planted in the ground, especially in well-amended soil. I wait for a killing frost before digging them. I cut the tops off, leaving about a 6-inch handle of stem. The stems are often as big around as broomsticks, so I resort to loppers to cut them.

Mingus Toni dahlia

‘Mingus Toni’ is my favorite dahlia, because in my cold climate it starts blooming in mid-July.

I use a garden fork, and start further out from the plant than I think I need to, a foot to a foot-and-a-half away from the stem. I stab the fork straight down, and then pry up. The goal is to get the fork under the tubers and lift them up without stabbing or breaking them. I usually try to rinse them, but I didn’t get to it this year. I’m not too worried, because they wintered over just fine in their pots, covered with soil, at the old house. I put them in cardboard boxes, making sure to label the variety on the box, and store them in the coolest part of the basement. The hardest part is finding a big enough box, because the clumps can get really big, and I like to plant them big in the spring, so I don’t want to divide them.

Eucomis (aka Pineapple Lily) I’ve been thinking about trying this bulb for several years, so when I saw some at the Ithaca Garden Fair I snatched them up. They were small offsets from a home gardener and as I suspected didn’t bloom this summer. I removed them from the big pot they were in, shook off as much soil as I could, and then put them in a labeled paper bag, stored in the basement. Hopefully they will grow to blooming size next year. Eventually I want to try some in the ground, inspired by this comment by the Berkshire Botanical Garden, stating that they grow it in the ground in their Zone 5b garden.

Four O’Clocks (Mirabilis jalapa) Someone gave my mom a ‘Limelight’ four o’clock plant. I decided to dig it up and save the tuber, just like I used to do with Mirabilis longiflora. Four o’clocks are easy to grow from seed; why would anyone grow it from a tuber? Because if you start it from seed, it takes longer before it starts flowering. I confess, I have a thing for chartreuse foliage and I would grow it even if it didn’t bloom. Chartreuse foliage looks great with colchicum flowers.

Geranium (As in Pelargonium the bedding plant geranium that we treat as an annual, but is actually a tender perennial.) There were two in each hanging basket that I got for my birthday (pictured near the top of the post). I was inspired by this post in A Garden For The House showing how to rejuvenate geraniums to bloom in the winter. I think I started too late to get them to bloom this winter, but if they make it through the winter I can take more cuttings to grow next spring.

Many other sources say to let them dry out and go dormant, and revive them in the spring. I’m trying both. Besides the two on my windowsill, I’ve got two in the basement that were pried out of the hanging basket and put into a plastic grocery bag, which I loosely tied up. I just went to check on them, and they’re not very dormant. I see pale, yellow growth through the bag. Not sure what I should do about that–if anything.

Gladiolus My husband loves glads. For several years I bought a bag of mixed colors for him to plant in his vegetable garden. He always admired the dark red ones the most. Finally I got smart and bought some deep red ones: ‘Espresso’ and ‘Black Beauty’. Some of the mixed color glads have come back three years in a row, but I’m not taking any chances with these dark beauties. I dug them up, clipped the foliage off, removed the old shriveled corm from the new one, and put them in labeled net bags. They’re down in the basement with the rest of the stash.

black beauty or espresso gladiolus

Here’s one of those dark red glads leaning into Rudbeckia triloba.

Hibiscus I got a Jolly Polly tropical hibiscus as swag at the latest garden communicators national conference. Some grow it as a houseplant, and others let it go dry and dormant. Right now it’s in the dining room with all the other houseplants. I’ve only watered it once. I guess I don’t have the heart to totally withhold water, and as long as it’s green I don’t want to put it in the dark basement. Kind of sitting on the fence with this one.

Jewels of Opar (Talinum paniculatum ‘Kingwood Gold’) I grew this from seed this year and it looked great with dark purple heucheras and magenta-pink colchicums. I had it once before when it came in with another plant from a Tennessee gardening friend. Everything I read said it would self-sow but it didn’t here.

Kingwood Gold talinum

‘Kingwood Gold’ looks great with ‘Grape Expectations’ heucheras.

I got seed and grew it again and had five plants this year. I’ve dug the tubers and stored them in a paper bag in the basement. I’ll replant them in the spring and we’ll see how that goes. In the meantime, a Pennsylvania friend gave me some seed. Many people in warmer climates call Jewels of Opar invasive. Keep that in mind if “warmer climate” is where you live.

Rain Lilies (Zephyranthes) A friend from Texas sent me some rain lilies. I thought they were going to be annuals for me until I read on Old House Gardens how one of their customers keeps them going in Wisconsin. I had planted mine in the ground, so dug them up in the fall and replanted them in a clay pot. This year they didn’t bloom much, and I wonder if it’s because they were disturbed. Mine are still in their pot in the dark part of the basement with the other stored plants and still have green leaves on them. I don’t know what it’s going to take for them to dry out and go dormant. I’ll bring the pot back out in the spring.

Rain lilies around a dahlia

I grew rain lilies in the garden before I learned they could be wintered over in a pot.

Rosemary (Rosmarinus officinalis) I winter over a rosemary every year, and I wrote about it here. We’ve moved to a new house since I wrote that post, and I finally did get a ‘Salem’ rosemary. At our current home, we have an attached garage on the southern side of the house, so there are no south-facing windowsills for plants–except in the semi-finished room above the garage. It also happens to be quite cool up there, perfect conditions for the rosemary. Well, good enough conditions. Our winters aren’t sunny, so even in a southern exposure the rosemary doesn’t get as much sun as it would like. It also get aphids every winter, but I just ignore them and once the rosemary is back outside, they disappear within a week. I do have to set a reminder for myself to check if it needs water every week, otherwise I would completely forget about it. I rarely go up there.

Salvia There are lots of tender salvias and the advice is to “take cuttings to keep them going.” This year I took some cuttings from a particularly attractive salvia at the same time I took the coleus cuttings. I’m pretty sure they rooted. You’re supposed to look for new growth. With the low levels of light in the house, there hasn’t been much new growth, but I think there’s been some. At any rate, I removed the mini-greenhouse covering (just a lettuce mix container) and they haven’t wilted, which means it’s time to pot them on. I followed the directions on taking cuttings in Making More Plants by Ken Druse.

Lemon Coral sedum

Lemon Coral™ Sedum mexicanum in a container my daughter painted.

‘Lemon Coral’ Sedum (Sedum mexicanum) I love this plant. It mixes so well with other plants in a container, but it’s not hardy here. It was a trial plant sent to me by Proven Winners, and they say it does well as a houseplant, so I’m trying it this winter. It fell apart as I was digging it out of its summer home, so I have it in several different pots growing in different locations in the house.
lemon coral sedum growing in cow creamers

Because the sedum is shallow-rooted, I’m having fun growing it in unusual containers, like these repurposed cow creamers. There’s no drainage, so I have to be careful to avoid overwatering.

Golden Sweet Potato Vine (Ipomoea batatas) There were two of these vines in each hanging basket I got for my birthday. I replanted two in a hanging basket and I’m growing them as a houseplant. I harvested the tubers for the other two, tossed them in a paper bag and they’re in the basement with all the rest.

golden sweet potato in hanging basket

The vines get light from two different sources and so far they’re looking pretty good.

packed up plants

Here’s the whole stash before it went in the basement. The two hanging baskets hold tuberous begonias. The two small pots are angelonias. The two boxes have dahlias. Everything else is bagged up and in the black crate.

About that basement I keep mentioning

It’s neither as cold or as dark as recommended. Since we had our heating system renovated, our basement temps hover around 60°F (~16°C), when 40°F (~4°C) is most commonly recommended. We actually have a lot going on in our basement: a washer and dryer, a pantry, a second stove, and two freezers–and a large household that uses them all. Not everyone who goes down there remembers to turn the light off when they come back up. I did box and crate everything and stuck it all in the crawl space part, so my plants are in the darkest and coolest location, but it’s not ideal. But that’s part of the experiment, to see what works for me in my not-ideal conditions.

About the Author

Kathy Purdy is a colchicum evangelist, converting unsuspecting gardeners into colchicophiles. She would be delighted to speak to your group about colchicums or other gardening topics. Kathy’s been writing since 4th grade, gardening since high school, and blogging since 2002.

What differentiates a bulb from a perennial plant is that the nourishment for the flower is stored within the bulb itself.…There is something miraculous about the way that a little grenade of dried up tissue can explode into a complete flower.

~Monty Don in The Complete Gardener pp. 142

Comments on this entry are closed.

Sharon December 13, 2018, 11:31 am

I also over winter in the basement but I have 4 T5 4 Ft bulbs and 2 normal flouresceent bulbs over my plant table & floor area. I have geraniums and mandevillas blooming now. I used to store canna in a plastic tub in vermiculite. That worked well but they take forever to regrow and bloom so I don’t bother anymore.

Harley December 13, 2018, 9:44 am

Thanks Kathy. This was a informational read for me. Every year we wonder what we can do with our harsh winters in Minneapolis. The post is now getting me thinking about carving out some space in the basement and keeping the growing season going. I especially love the Sweet Potato vine, it’s so bright for these winter months.

Kathy Purdy December 13, 2018, 6:35 pm

Harley, I’m glad you found my post helpful. You can grow even more if you use your seed starting lights to winter over plants. For example, see Sharon’s comment above yours.

Mary Schier December 12, 2018, 2:43 pm

Wow! You’ve got a lot going on there. I’m kicking myself for not wintering over some of the coleus I had last summer, but the Lemon Coral sedum is doing great so far. The scented geranium I brought in keeled over in about a month. Rosemary seems especially happy in our front room. Looking forward to hearing how your experiments work out!

Kathy December 12, 2018, 11:21 am

I LOVE experimenting! You do have quite a range of experiments here. I have successfully grown pineapple lily in large pots and then thrown the pot in the basement for the winter and have them regrow when I put the pots out again in the spring. Before I said the heck with it and moved to FL, I used to just use houseplants as my container plants. Begonias and oxalis worked really well. Bulbs also work well because they do need that dormant period and I would just chop off and store in the basement. Now I buy tropicals and just bring them down to FL to plant in the ground here ha ha ha. I bet you have a stunning container garden come spring Kathy!

Rhonda December 10, 2018, 3:59 pm

My basement is just like yours and I don’t have a garage or shed so overwintering is tricky. I can usually get amaryllis to go dormant but not much else. I do have grow lights in the basement so I overwinter fuchsia, rosemary, sweet potato vines, purple heart. I’ll be interested to see how your experiments go, especially the 4 o’clock tuber. I might try that next year.

Joanne Toft December 10, 2018, 9:15 am

I have geraniums bare rooted, elephants ears, and begonias each in brown paper bags in a cool dark basement closet. I mist them once every 5 to 6 weeks during the winter and them repot them in late winter. This is year 4 for all of them.
Thanks for all the detail you provided and links to others blogs.

Carol Eichler December 10, 2018, 8:16 am

My sunroom gets totally overtaken with big pots of plants that go outside in summer – a mix of the “normal” houseplants and choice tender perennials. I’ve saved myself lots of $$ by not buying the tenders from year-to-year. If only I had a basement…I’m sure the stash would grow crazier.

Gail December 10, 2018, 7:44 am

That’s an impressive number of over wintering plants! Oh I envy you that basement.

Lisa at Greenbow December 10, 2018, 7:04 am

Your experiments will keep you busy this winter. I brought in fewer plants this year. One year I pulled some geraniums and tossed them under the house right by the crawl space window entry. I forgot about them. Then the next spring I noticed something red in the crawl space window. It was a geranium bloom! I quickly got them out and repotted them. ha… Even though this worked I haven’t done it since because I just don’t have enough sun to make them bloom as they should. It was a fun experiment though.