my ‘secret’ to overwintering japanese maples
NOT YET, BUT SOON. That’s when my Japanese maples will go back into hiding for the winter, to protect their tender twigs and beautiful bark from winter winds and ice and sunburn (and mice and voles and who knows what else rampages around outside here on the coldest days). It’s the most common question I am asked during garden tours here in spring and summer: What do you do with all those huge pots of Japanese maples come winter? This is what I do:
Once they have dropped their leaves and gone dormant, after a good hard freeze or so, I get out the hand cart and engage a brave friend. We say our prayers, then wheel them one by one over my hilly garden, down to the unheated barn.
I will certainly meet my end someday under one of these big pots, when I am manning the downhill side of this hauling operation.
I make sure that they are well-watered during the fall, so that they go into storage well-hydrated—and therefore less prone to dessication while in there. No water is offered in the coldest months, when the soil and the trees inside the building are mostly frozen, but I start checking around February, once the slightly longer days are starting to nudge plants to awaken, when they may need a little—especially in March and April.
My barn has windows that let in a little light, but that’s not needed, or even wanted; darkness is perfectly fine for dormant things, and late in the winter or early in spring, too much light will just make them want to awaken faster than you desire.
I keep the pots inside as long as I can—sometimes right up until the end of April—and I don’t move them into their season-long spots (which are far from any easy cover, should nights get frosty) until the weather really settles. I simply wheel them out and set them near the barn, just in case of a “fire drill.”
Some gardeners root-prune lightly every couple or few years when potting up gradually to a larger container, to tell the tree to stay small–almost as if making bonsai.
Yes, many species and varieties of Japanese maples would be perfectly hardy here in the ground in Zone 5B (including some in the link at the first bullet below), but between cracks in the bark from sunburn and broken branches from ice storms and–on the other end of winter–fried fresh foliage from late frosts and wind, I’d rather not bother. And besides, they make such beautiful subjects for pots.
Which is why everyone always asks about them.
- Read a lively discussion about Japanese maple hardiness on the University of British Columbia Botanical Garden forums.
- If you want to growing Japanese maples in the ground in a cold zone, site them where the winter sun isn’t strong, and where the wind won’t whip them.
- My thoughts on overwintering other tender plants, in addition to the potted maples.
Abby says
I’m in 5A and my Japanese maple is in the ground in front of my dining room window. I accidentally killed the original Japanese maple that was in this spot – smothered the roots – then failed to keep the subsequent lacy leaf one sufficiently watered. But I’ve learned my lesson and am on year 2 with the current resident. It has been dry, so I have been watering it until it goes dormant. There is a variety of redbud that is kind of sensitive, but now you have given me the idea of trying it in a big pot. Thanks!
Johanna says
I found a Japanese maple half off a few weeks ago, and put it in a big pot I happened to have around. I’m hoping it will be as happy there as yours are! Still covered in leaves so still out in the yard, but the forecast is for a big change in the weather this week, so it might be almost time for the move…
LarryM says
What are your pots made of? Any tips for keeping the pots from cracking? I’ve overwintered a couple of plants, but it seems the freezing/thawing cycle is tough on the terra cotta pots.
Margaret says
@LarryM: The biggest ones are fiberglass, though some pretty big ones (thigh-high) are terra cotta. The key is that they cannot get rained on and snowed on and then melt and freeze up and melt (freeze and thaw), another reason I put them inside. In the barn, they go into there already frozen and basically stay that way. If they defrost a bit in the winter momentarily, it’s fine, because they aren’t all soggy from melting snow/ice so they don’t heave from the extra moisture freezing up. I have had some of the big terra cotta for more than 15 years — the only casualties have been when they fell off the hand cart on the downhill ride!
deegrubb says
after reading your post about pushing the japense maples uphill and the worry you will be on the downside of a falling pot, my husband has made me aware that it is much easier to pull uphill than push, try it, I think he may be right, just don’t let him know.
Margaret says
Welcome, Deegrub. I have a helper, and because each pot outweighs either of us we double-team the operation: one person on either side. I typically push (to help keep the pot on the cart and offer more oomph) and my helper pulls (from the uphill side). What we need is for your husband to come over here and help us. :)
Darrel Schoeling (Longitude Books) says
I’ve put a Korean Lilac in a big wooden tub, where it has thrived the last three years in a semi-sunny, protected spot, ignored by the deer that rampage in Ulster county. Should I do something to keep the cold from killing it or is it just as happy in a pot as in the ground?
Sheri says
My husband and I were heartbroken when we lost our beloved Japanese maple to verticillium wilt a few years ago. Planted in the east-facing garden in front of our front porch, its leaves shown like stained-glass in the early-morning sun. Now after reading that JMs will overwinter well in pots, even in northern Iowa, I’m buoyed and will be shopping for big pots and new trees in the spring. The new garden shed we plan to build come spring will make a fine winter home for our new beauties.
Lorraine says
Upon cleaning out my window boxes a few ays ago, I found several sweet potato tubers at the roots of the sweet potato vines that were planted in the boxes. Are these edible? thanks lorraine
Margaret says
Hi, Lorraine. Technically, yes, but they are not as nice tasting as the ones cultivated for eating. Also, and it’s a big also: nursery plants from the garden center are usually sprayed with various things and fed others that are chemical-based, and you don’t really want to eat any after-effects of that. So on both counts, I say don’t eat them. You can grow them again next year if you keep them from freezing all winter (like in the dark basement, just in their pots but basically dry and dormant).
star says
Hello – I have a newly planted Japanese maple – I live in zone 5a. I know I need to protect it – but how?!? I know to put protection around the base, and then mulch, mulch, mulch – I bought stakes and burlap – but it is a pagoda style – how do I keep the branches from snapping off? Do I make a tee-pee below the branches and then just constantly brush the snow off? thanks!
Margaret says
Welcome, Star. I think brushing at it too much when the delicate twigs are frozen and maybe covered in ice is an invitation to snapping things. Do be gentle if it comes to that. Also, you can’t really erect something unsturdy that will inadvertently catch the snow and ice because then the whole “protection” device could just collapse onto the plant — like a burlap cover overhead would do.
I have seen structures (temporary ones, but well-anchored) made of lightweight wooden lattice in a chalet (upside-down V) form, and I have seen people use “snow fencing” lattice as well on the windy side and so on. I have never done any of these things myself — so windy here in winter, I just think it would be quite the undertaking. Sorry not to have first-hand advice.
Liz says
could I do that here in Cranbrook, BC ? zone 3-4?
Margaret says
Most Japanese maples are at least Zone 6 hardy (with a decent number that technically survive in Zone 5, where I am, but can get a little ragtag in the process, so you see them listed as Zones 5-9, but I prefer to protect them; a neighbor of mine grows them outside in a protected area of his garden). Pushing them as far as Zone 3-4 seems like a big stretch. I have succeeded with pushing things a half-zone or a zone, but remember: their roots will still be out in the cold, so to speak, even inside the garage — so you can still kill them, even out of the wind and ice.
I grow the Korean maple, Acer pseudosieboldianum, in the ground (it’s Zone 4 hardy, and looks like a Japanese maple, with fantastic fall foliage color in particular). I bet you could apply the same tactic to that.
jina Kessler says
Hi Margaret Enjoyed your talk at Tower Hill and your book. I have an 8″ JM not sure of the variety in my garden that has survived for 5 yrs at least but, has not grown much. It was a seedling I snagged from my sister’s garden in Mt. Kisco . Do you suggest I pot it up and move it to the unheated shed then keep it in the pot for the summer in a sunnier location? I don’t believe it is getting enought sun and needs to be moved. Should I wait till March before it leafs out. I am in zone 5 central MA. Thanks for the input.
Jina
Margaret says
Hi, Jina. Thanks for the kind words! If it’s that small, the pot you’d put it in would be very small, too, and wouldn’t provide enough insulation to the root system in the garage over the winter, so you’d have to “plant” that pot in a much bigger one foir extra protection. But the idea of moving such a small seedling now, before the hardest weather, seems harsh. Wait till early spring, pot it up in an appropriate container and give it some love (then tuck that pot into a bigger one of potting soil or peat or mulch for the winter, as I say — you cannot overwinter very small pots up our way, even in the garage!).
jma says
In late fall, my son “plants” his small JM bonsai trees in the garden and puts an upside down bucket on them when the snow, icy rains start. (He gets the big buckets at the paint store). Our big potted plants get wrapped — lots of sheets of newspaper inserted flat into big plastic bags until the package is about 2″ thick. Sometimes it takes two of these wraps to reach around the pot. Fasten them together with duck tape vertically, then wrap the tape horizontally at two or three points so the wrap hugs the pot. This technique has worked well for over 10 years in zone 5.
Margaret says
Welcome, JMA, and thanks for the good tips on the other way to keep them tucked in safely, without moving them as I do. Very helpful…and tempts me to want to go buy some more!
AC says
Hi Margaret! I loved this JM post. I read it voraciously several times. I have two hardy JM’s planted in the ground on a west facing hill. in front of the house. They get full sun all day. The big one is a regular JM, the one next to it is a lace leaf dwarf JM. I loved how they look together, so I planted them side by side with juniper underneath. This year I added a peony down there, too. So far, so good. Here’s the rub: they’ve been in situ for 3 summers. However, this spring, a big wind knocked the larger one out of the ground, so I replanted him, soaked him, and staked him. He seemed to be struggling for a few months, so I started to layer on rotted manure every month or so, then mulch, then a good watering every week or two. He seems to have new leaf growth, but I’m wondering, should I keep him staked this winter, too? When do you suggest I remove the stake? Many thanks!
margaret says
Hi, AC. The only reason to remove the stake would be if more wind/weather might buffet it and make it rub/slap/bang against the tree and do more damage. Otherwise I think if it’s well-anchored and not going to do any harm it might help!
ecm says
Hi Margaret! I’ve been wanting a JM for years and finally bought 2 little seedlings this spring. Since they are tiny, maybe 6″ tall, I have them each in a smaller plastic pot that I “planted” in a larger wine barrel pot. I was planning to take them out and wrap them up and put in an unheated shed but after reading all these posts, I’m no sure what to do. They are dwarf maples that state they are hearty to zone 5 and I’m in zone 5b. Thanks!
margaret says
Hi, ECM. Remember than a plant in a pot (meaning without insulation for its roots from the earth) is a zone and a half or thereabouts more vulnerable to winter effects. So whatever you do, you want them to have soil volume or some other insulation around their roots — not just sitting in a shed in a little container. EVen when mine were young, I had them in large pots (at first “plunged” inside a nursery pot into the large container, and later planted). Mine were never 6″ seedlings in the years I have had them, though — I started a little bigger, maybe 18″ or so, so they were in gallon pots I think — again, which I plunged in a big pot for awhile).
Mike says
Hi Margaret! Thanks for the great post. I have a question about JM seedlings. I’m in Vermont (4b) and I have some seedlings from my moms place in Connecticut (5). The seedlings are only about 6″ tall and 6 mos old. What should I do with them for the winter? Similar to what you do with your potted JMs? Thanks!
Kevin says
I just planted a crimson queen japanese maple in a raised bed. No walls just tapered soil to ground. Have hard clay here in zone 5 southeastern Ohio that’s why I chose a raised bed. I know I’ll need thick mulch layer and proper watering through fall. Any other tips for raised bed would be helpful. My first raised bed and Japanese maple. Need all the help I can get. Thanks
margaret says
Hi, Kevin. Not sure how that will work — I have never tried it. Since it’s above ground level it will have more root exposure in winter than when in the ground (making it a little less hardy, I expect) plus depending on the scale and stability of the mound, hmmm…where will the upper roots go in a sideways direction, and will there be erosion of the mound, leaving the plant’s roots high and dry? Maybe you made a really, really big mound to accommodate the eventual root system of the mature plant.
John says
I live in zone 3 and just got a emperor 1 JM. I was planning to keep it indoors as its about 7ft tall. Do you think it would be ok to but it in the basement with no light for the winter months once it goes dormant? I think placing it in the garage may still be too cold. And during this time do I still need to water it?