IT IS NOT TIME quite yet here for what I call the mad stash, storing those non-hardy plants for the winter that we wish to keep alive for another year of service. But it is time to make some plans to do just that.
Marianne Willburn, author of “Tropical Plants and How to Love Them” (affiliate link), and a serious mad stasher, is here to help us puzzle out what goes where for best results. Marianne is also a contributing editor to the collaborative blog called “Garden Rant.”
We’ve both been stashing many kinds of investment plants over many years, with wins and losses along the way. So we wanted to compare notes to help you fine-tune your strategic plans for adapting spots in the house, cellar, garage, wherever, to improve your overwintering results with tender treasures (like Marianne’s bromeliads grouped in a terrarium on a pebble tray, above).
Plus: Comment near the bottom of the page for a chance to win a copy of the book.
Read along as you listen to the Sept. 18, 2023 edition of my public-radio show and podcast using the player below. You can subscribe to all future editions on Apple Podcasts (iTunes) or Spotify or Stitcher (and browse my archive of podcasts here).
overwintering tender plants, with marianne willburn
Margaret Roach: So just to sort of set the scene, Marianne, we should tell people where we garden and what our realities are that we’re stashing things against [laughter]. I’m Zone 5b in New York State, Hudson Valley, and maybe I can get to minus 10 or minus 15. Sometimes we don’t. I can have frost in May, even late May. I can have it as early as late September; sometimes it’s not till mid-October. What about you? Where are you?
Marianne Willburn: I am in Northern Virginia. I am in 6b. Some people like to sort of think they’re in 7, but they’re not [laughter]. We’re in 6b and it can get down as low as negative 5, but zero is usually around where we are. Our first frost is usually around October 15th. It can go as late as November 1st, and when it does, it just means we’re all exhausted, because we can take on so much more work as the season goes on.
Margaret: Oh, yes.
Marianne: You probably know that deal, right?
Margaret: Yes, yes, yes. Yeah, we don’t want the frost or the freeze to come, the hard freezes to come, but on the other hand… It can mean, “Oh, well, I’m done with my chores for this year.” [Laughter.]
Marianne: Oh yeah. When I go down to Florida for Tropical Plant International Expo in January, and I see everybody working so hard down there, I am so thankful to have a break.
Margaret: Right, to not have a 12-month season. So, I just wanted to compare notes on what spaces we use in our home kind of worlds, what places we call into action. I store things in my cellar, which might be 40-something degrees, certainly under 50, but above 40. I have an unheated barn that I use for some things, and of course even the house in some cases. What about you? What are some of the spaces?
Marianne: Yes, there’s some similarities there. I have a garage that’s frost free, stays in that sort of 35-to-40 range because the boiler is there. I used to do the same thing in my cellar, like you did, in my last house. I used to keep things in an unheated barn as well, but I’m staying closer to the house these days, and I keep things as houseplants, which are really happy as houseplants. And then I keep sort of my “ugly corner” [laughter] of the high-maintenance plants that are not happy being houseplants, but they get to cope together in shared ugliness, and my care, and a little bit of added humidity from being close together. And I use ugliness as a little bit of a joke. They’re not as beautiful as some of our classic houseplants.
Margaret: Right. Well, and really, I mean you were just saying “as houseplants,” so you’re not talking about your traditional houseplants that might even be indoors all year. You’re talking about plants that you bring into the house and say, “O.K., can you cooperate enough to stay alive for the winter?” [Laughter.]
Marianne: Exactly. “Can we just make it through a few months together? And this might not be great for you, it might not be great for me, but the end is just to get you through this time period.” And I do different things to make that happen. And also a couple different places in my house. I always go for the coolest place in my house for those kind of plants because the cooler, the better in a drier condition. So if I’m away from heating ducts, and particularly one of my rooms that doesn’t have heating ducts, that’s the best situation for those plants.
Margaret: Right. So what we’re getting at then is that we need to do a little kind of analysis of… And a lot of this is trial and error. I mean, I’ve had plants that the first year they lived with me, I didn’t make them very happy, and then I kind of figured out, you know, I read the feedback they were giving me, and I did better the next year and so forth. But it’s sort of: can we keep it in active growth, or should we let it go dormant, or is it sort of going to be (like you talked about the ugly corner or whatever) that it’s sort of somewhere in between. They’re not really active and lush, but they’re not really totally fully dormant in the cellar, in the dark, in the cold.
Marianne: Yes.
Margaret: So how do you, give us some examples of some of the ones that you keep awake, let go to sleep, you know what I mean, what’s in which spaces?
Marianne: Yeah, A really great example of that are some of my smaller Alocasia, and Alocasia has become a popular houseplant. The elephant ears, but very specific elephant ears.
And these plants, in fact, I was just talking to a grower the other day who said, “I don’t know why these are houseplants.” Because the spider mites want them. These are very different than Colocasia, which, no way are you keeping as a houseplant. If you are, you are amazing. But Alocasia are a little bit thicker, a little waxier sometimes. They’re usually an upright leaf. There’s a few other things that are a little bit different about them, but those are all generalities.
And these plants, they don’t necessarily want to go into full dormancy. You can put them into full dormancy in that cellar of yours just frost-free. But they would rather stay “in the green” and they’d rather stay in sort of a stasis situation, where they’re 50, 60 degrees, just sort of getting through. Well, I can’t give any of my plants that kind of, “Oh, sure, I’ve got a part of my house that’s 55 degrees.” [Laughter.] That’s really tough. So I put them in the coldest part of my dining room for the littlest ones. The big ones, I don’t care. You’re going into dormancy, you’re going into dormancy in the garage, you’re big enough to handle it. [Above, ‘Pharoah’s Mask’ and ‘Morning Dew’ Colocasia at Marianne’s.]
Margaret: Because you can’t really accommodate them otherwise. I have friends who have a sunroom and it has a little heat, but it’s not super-heated. And that’s the kind of space. And I have another friend who has kind of like a mudroom, vestibule kind of thing that can be closed off a little bit, but it has windows on two sides. And so these are these transitional spaces that we can sometimes pack with plants that want that stasis that you’re talking about.
And without making our house, the whole house, super-cold or whatever, and without exposing them to the heat of the main house, you know, the main parts of the house where we were living. But not everyone has that space. Not everyone has that space.
Marianne: No, we’re aiming towards as cool and dry as possible, not meaning we want them to be dry, but you don’t want them to be cool and wet. That’s really bad. Cold and wet is bad, that’s rotting.
But what we have in our houses usually is warm and dry. And that on one hand tells a plant, “Grow, it’s warm.” And then on the other side, on the moisture side says, “Stop growing. There’s no moisture.” And so you’re putting these plants into this split-personality situation where they go, “What, do I grow? Do I not grow?” And then they just spiral down into death spiral. So we want to push towards the coolest that we can for these pickier plants.
Make some choices in the fall when you’re tired, this is the best time to do it. I know you’re tired, I’m tired. You’re tired of rain, I’m tired of drought, and this is the time that you make those choices so you don’t baby a plant through the winter, go through all this trouble for it and then in the spring, “Oh, O.K., well I have to find a place for that.” Because spring has come and you’re excited and everything’s great, but now you’ve got a huge workload. So making those choices right now, being discerning about, “Do I really need that plant? Did I love it this year? Did it do a lot for what I was trying to create on my deck or patio or garden?” That, I think, is the best place to start. Let’s be really discerning in what we need to keep first and then figure out how are we going to keep them.
Margaret: Yeah. And this is going to take some homework, and again, like I said earlier, trial and error. And I think the Alocasia and Colocasia, the elephant ears that are all lumped together. There’s been so much interest in them in the last, I don’t know, 15 years or whatever. There’s a zillion different ones and they’re all a little different. Some make, like the Colocasia, I think they make more like a, is it a tuber or a rhizome? I don’t even…
Marianne: It’s a corm, yeah.
Margaret: A corm, okay. And so again, you can kind of put them to sleep in the cellar the way you can, your Canna or whatever. But some of these other ones, the more showy, newer cultivars, especially the Alocasia, not so much. And what I’ve had happen is I’ve tried to keep it limping along and then I’ve tried the dormancy. I’ve tried both. And then the thing doesn’t want to wake up when I want it to wake up, which is in spring, so that then I can enjoy May, June, July, August, September, my only frost-free season. It might not wake up till July or August [laughter].
Marianne: Oh, yes. And I had that happen this year. Yeah, absolutely. I was so late getting things started because of a really big speaking schedule. So I got it late. I really only got my Alocasia moving about three weeks ago. Well, hello. It’s July.
Margaret: Exactly, exactly. So this is the thing is that sometimes you don’t kill it, but it backfires for the utilitarian value of the plants. So we need to also find plants that, as you talk about in your book, are kind of our best friends and good companion, I know you have different phrases for them, but into the different chapters, you kind of group them in these charming ways, almost anthropomorphizing them.
But we need to find ones that are suited to the conditions we can realistically offer and not spend $50 on something that, unless we’re O.K. with that, that we might not be able to overwinter.
Marianne: Yes, absolutely. I mean that $50 that you spend in May for something that’s going to last easily until the beginning of October, end of September, that’s a pretty decent investment for what is in effect a flower bouquet that lasted that many months. Right?
Margaret: Right. It is.
Marianne: That’s a summer romance. But we might not want to do that with that many plants [laughter].
Margaret: Right, and on the other hand, I might for that price buy a young shrub and I might put it in a big pot, a shrub that’s at least as hardy as my area or maybe a little hardier. And I might put it in a big pot and I might then drag it into my garage for the winter. And I might have that as a piece of portable garden decor for 10 years. Or I might end up putting it into the ground when it gets big enough, moving it up into a bigger pot once or twice and then putting it in the ground. So it depends on what we think an investment, a good investment and a good return on our investment is. And for each of us, that’s something different.
Some of my best were shrubs or Japanese maples, small Japanese maple trees that I’ve had 15 years in a progression of larger pots. And every year they’re key fixtures in the garden. They’re like my “annuals” because they lived the rest of the year in the barn, but they’re great [laughter].
Marianne: And very personalized. They’re going to be different for each of us. We can do that with some tender plants like Brugmansia or Plumeria, which can just get pulled into the garage, just kept above freezing, can be stunning, come back very quickly in the spring, and that makes a lot of sense. But if you’re doing that with the Alocasia that we talked about, and it’s taking so long, it doesn’t make sense. So figuring that out for yourself, that’s really important.
Margaret: If you want a good return on investment, buy cannas [laughter]. [Canna rhizome, above.]
Marianne: Oh yes.
Margaret: Because they’re rock hard, they just, I swear, I mean I never lose any, they just go into the cellar and they’re just happy and it’s no big deal. I actually ended up buying, I have so many of them now, I ended up buying a few… At the like Dollar Store or something, the hardware store, I ended up buying a few of those plastic laundry baskets. It’s like plastic mesh. It’s just a big laundry basket with the two handles, one on either end. And it’s like I just put them in there, carry them downstairs, and then I put a sort of a tarp loosely over the whole thing and that’s the end of that. And then I carry them back up in the spring. It’s easy.
Marianne: It’s ridiculous how easy they are.
Margaret: Yeah. So what about, one thing I love and I’ve had mixed success because there’s so many actually different types of plants within this group, but what about the bromeliads? How about those? Because, and some can be grown as houseplants and some are more fussy. And what about that? Do you have any of those in your collection?
Marianne: Oh, yes.
Margaret: Because they’re so gorgeous and they’re so wonderful for outdoors in a sort of indirect light kind of, I think. Some of them can be in the sun, but some of them in a bright spot. I love how they look.
Marianne: Yes. You’ve just touched on probably my favorite group of plants because they’re fascinating. They are statement-making and they’re still very different. When you can get your hand on a good one, you keep it. I have tried to keep my collection small so that it’s workable.
These plants need, over all, a little bit more humidity if you can give it to them. And so what I’ve done is in a place in my office, which is cooler, it’s absolutely freezing to me in the winter [laughter], I have a terrarium in there that’s open on the top and a pebble tray in the bottom of that terrarium. And I can get about four to five bromeliads in that. And they sit on that pebble tray that I constantly fill with water, and that extra humidity that’s built because of the glass sides of the terrarium and the fact that these plants are close together.. They do need some air movement as well; they’re finicky about that, but that allows them to do really well. And they’re in a sunnier window, so they have a little bit of light. I’ve got a mister when I’m feeling bored and in the middle of an article that I’m just mind-blocked on, I can just sit there misting them, thinking about it.
So, they work really well. This last year I had a Vriesea bloom for me in the middle of the winter and I’m like, “Well, I’m doing something right with these guys.”
Margaret: Wow, good. Oh, yeah, yeah.
Marianne: And then of course my Tillandsia, which are bromeliads, those are my air plants. Those are even less care needed. Those decorate the kitchen. I love putting a xerographica, Tillandsia xerographica [above at Marianne’s], up in where my rolling pins are that come out, a few of them are in my kitchen.
Margaret: [Laughter.] A little creature. A little creature.
Marianne: It is. And those are fun. And they just get a bath once a week. They get a nice dunk once a week and they’re good. The bromeliad, sort of the ones that people think of as bromeliads, the Neoregelia, Vriesea, Aechmea, those type of things, those I fill the funnel and let them have enough water at that way.
Margaret: So that cup like central at their crown, a cup-like area.
Marianne: Yes. And I mean, I remember Liz talking to somebody at Bullis Bromeliads down in Florida, really wonderful grower, and she was saying, “Don’t fill the cup. It can be bad in the winter.” But that hasn’t been my experience.
Margaret: No, not for me. If I don’t fill it, they look unhappy.
Marianne: Yeah, and so that has also shown me that what is working for one person may not be working for another and that we have to play with these plants. Trial and error is one way of saying it. I like to say playing with them, because we’re figuring out what our boundaries are, our limits are with them, and how they can respond to what we’re giving them.
Margaret: Yeah. And there’s some no-nos, like you talked about warm and dry. Some places in our homes are just impossible for certain types of plants, like the ones you were just talking about. They’re not going to be happy in a super-dry, super-warm spot, the bromeliads probably. But if a plant wants to be sort of asleep and you keep soaking it, keep watering it and stuff, that can also cause its decline. Do you know what I mean? It’s like forcing someone to be half-awake or three-quarters awake who doesn’t want to. Or if it’s too cold and it’s cold and wet, that’s a really bad combination, too. So it’s also sort of figuring out that and when to back off.
Marianne: I mean ideally I would love at some point to, I just got a greenhouse last year, got it all up and going. I would love to heat it to about 50 and put all these guys into stasis there, but that’s going to be really expensive and may not be worth it to me.
Margaret: Yeah. And it’s a lot of work, too, because something always goes wrong. There’s always an emergency. Everyone I know who has a greenhouse there’s… I’ve never had one, but there’s always some emergency, some drama.
Marianne: Yeah, And I think that there’s strength in this book in that I did all of this work with tropicals and subtropicals without the aid of that greenhouse. So it’s to show people, “Hey, you can do this without a greenhouse. You can do it with one, too.” But there’s ways of getting around it. And again, it comes to paring down the plants that make the most sense for you.
Some of my big statement-making plants outside are some of my best houseplants inside. Things like my large Schefflera or a very large philodendron that I have. Those, I’ve got a beautiful Beaucarnea recurvata, the ponytail palm. It’s fantastic inside, it’s fantastic outside. And so it’s a win-win all year long for me, the only downside to it really is just taking it in and out on the dolly.
Margaret: Right, and I agree. I think that statement sort of houseplant, plants that can be accommodated and are happy to be inside and can also be then used in our vignettes outside in the garden in the right spots. That’s your biggest 12-month plant, the plant you’re going to get 12 months of happy service out of. So I have a lot of those as well.
And I want to ask you about, sort of quick, “What to do with…” For instance, a lot of people have been growing these red Abyssinian bananas. Is that something, do you cut it back and bring it in or what do you do with that, for instance, real quick?
Marianne: I do. Those plants are very, very easy to store until they get very, very big. And then you’re going to start rethinking, “O.K., I can start again next year with a new plant.” They grow very quickly. But if you got something that’s maybe one to three years old, I dig it. It’s very, very shallowly rooted. Do not be afraid that those roots are very tiny just around the base of this plant. Take them into the garage. I wrap that rootball with an old towel, because it acts as a humidifier, basically, a regulator.
And then I put a plastic bag over the top of that and I put that into a large 10 gallon or 20 gallon trug that I can move around if I need to. But it pretty much stays in the same place.
Always store them vertically, because if you store them horizontally, and you’re going to want to because you want to stack them or something, they’ll start to grow ever so much and they will distort during the winter, and it takes a while to get them out of that.
You cut off all of those leaves, leave the growing point, you’re going to start to see some growth in the spring as the temperatures are starting to pick up at, I say spring, but let’s say end of February, beginning of March, as temperatures are getting a little bit warmer, that’s when you’re going to repot them and get them ready to be going outside for like a May… For you guys probably May 15th.
Margaret: Yes, exactly. Exactly. I just want to talk about some things we store because they’re tasty. [Laughter.] You and I both have a freezer thing going on. I can’t grow herbs year round outside, but I have enough, and so I freeze everything from parsley to various pestos of lots and lots of different green herbs, all kinds of things, tomatoes, and who knows what. So I freeze lots of different things. But you also freeze some of your sort of “edimental,” ornamental-edible tropical goodies, like gingery sort of things. Tell us a couple real quick of that you do, you freeze.
Marianne: Well, I am awash right now in turmeric [laughter], and so that’s one of them. And I do grow this as an edimental, it’s exactly right. It’s very beautiful in the garden. And those roots, those rhizomes are edible. And so I will do a couple different things. I’ll either leave them whole and just grate them straight from the freezer with a microplane onto the top of rice or what have you, give it that beautiful yellow color, turmeric rice. Or I’ll chop them very finely and put them in an ice cube tray so I can just add some turmeric to, I’m talking really fine. [Next year’s turmeric for the garden in storage at Marianne’s.]
Margaret: Yes, and I do that with a lot of my herbs too. Exactly. Make sort of like an ice cube out it with just a tiny bit of water.
Marianne: Yeah, and I’ll do that also with ginger, with young ginger, because I cannot ripen ginger the way that it needs to be ripened. So I get to have the young ginger instead, which is fantastic, chopped up.
I also save Kaffir lime leaves, Makrut lime leaves, because those aren’t always available for me in the winter, and that is the flavoring behind a good green curry.
Lemongrass. I’m actually going to be doing my lemongrass probably this week because it’s been so dry. So I’ll be cutting those and saving them in little bundles to put into the freezer. And that’s delicious. Not to chop up, it’s a flavor agent.
Margaret: Right. The way we use a bay leaf in a recipe.
Marianne: Exactly.
Margaret: Well I’m always glad to talk to you and the mad stash lies just ahead. If we can just make it to the finish line. I hope you get some rain. I’m so sorry. I would’ve sent you some, but I didn’t have control over it.
Marianne: That’s O.K. And can I just say, Margaret, I love the term mad stash. I’m going to use that all the time now.
Margaret: Oh, good. Because I’ve always thought of it like that instead of the mad dash, it’s the mad stash. So yeah, so I hope I’ll talk to you again soon. Thank you, Marianne. Thank you.
Marianne: Thank you Margaret.
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MY WEEKLY public-radio show, rated a “top-5 garden podcast” by “The Guardian” newspaper in the UK, began its 14th year in March 2023. It’s produced at Robin Hood Radio, the smallest NPR station in the nation. Listen locally in the Hudson Valley (NY)-Berkshires (MA)-Litchfield Hills (CT) Mondays at 8:30 AM Eastern, rerun at 8:30 Saturdays. Or play the Sept. 18, 2023 show using the player near the top of this transcript. You can subscribe to all future editions on iTunes/Apple Podcasts or Spotify or Stitcher (and browse my archive of podcasts here).
