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.