Dormancy for specimen Chinese elm

15 years ago

I have an 80-y.o. specimen Chinese elm that I've had for six or eight years. Since it gets very cold/lot of snow here in the winter, I've been bringing the elm in generally when it first starts getting around freezing at night. I move it (I can hardly carry it) into my unfinished basement, where it stays a pretty constant 55 degrees, and water it lightly. It is near a fluorescent light table with six smaller evergreen bonsais and there (12 hrs on/off) is also a basement window there. It gets some light, but not a lot.

In years past, it has dropped MOST of it's leaves when moved in. Generally, but about February or March, it's putting out new growth on a limited basis with a lot of VERY LONG small branches with leaves. When I move it outside, I prune it and it's done fine.

I'm wondering if I should leave it outside for a couple weeks' good hard frosts before moving it inside, to force it into dormancy. That way, it would need less light and water and might be better for it. If I did that, would the 55 degree temperatures make it break dormancy again? If that is the case, would an unheated garage (cold enough in the winter that it killed a couple of cactus and bougainvillea last winter) be a better option? The garage has 2nd story living space over it so it seldom freezes, unless we go away for an extended period and turn down the heat upstairs.

Any suggestions would be appreciated!

Comments (8)

lucy
15 years ago
In your area (6b), you could leave it out all year, as long as you can surround the pot with a lot of mulch and possibly keep it in something like an unheated shed or porch. Fifty-five F. is not cold to a tree, so while 35-40 might be ok if you are trying to keep it from freezing, it could withstand even colder temps (though as it's not used to them, I might not take a chance on that now). BTW, snow falling on it won't hurt at all, but even help insulate it - just be sure that you do a good (wide and deep) job of burying the pot in mulch partway up the trunk and a large area around it.
utnvpa
Original Author
15 years ago
The problem with leaving it outside is that it's in a large (probably 20 inch diameter X 5 inches high), and beautiful bonsai pot that I'd not be comfortable with burying in the ground. Plus, it's really heavy and would be quite a chore to get it out in the spring.

If I could get it to go fully dormant, I know it would need little to no light and very little water as well. I do have an unheated garden shed, but it's on the south side of my house and can heat up further than I'd want it to on a sunny winter day. My garage is unheated as well, and might work, but I'd be tripping over it all winter . . .

Maybe I'd better just stick with what has worked in the past and let it go semi-dormant in my basement.

Thanks.
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lucy
15 years ago
One thing I do suggest is that you not water so 'lightly'. C. elms need a good soak (within reason) relatively often, certainly compared to e.g. evergreens or conifers, whatever the season, and if you keep it indoors above 50 F., you need to make sure it does have enough water and as much sun as you can give it.
gardener365
15 years ago
One month of cold dormancy (after the leaves fall during fall for deciduous) or the same treatment goes for coniferous bonsai is all they need. It will be zonal as to where you live. For me in zone 5, I'd keep the bonsai outdoors until the snow starts flying.... but then you need to give it a greenhouse or good supplemental lighting. Weak lighting will give you thin and week growth. A south-facing window should do just fine though but beware of dryness of air within a home. Never put the bonsai near a heat register.

Mist it every now and then and like normal, allow the plant to almost dry out near completely between waterings. A few 4-5 mistings per day would be beneficial. That's how often I used to mist grafts in my greenhouses before I built a humidity chamber/box covered in thin clear poly.

But a month is all anything non-tropical needs. You're best bet is to wait until it starts turning to winter, as I say when the snow starts flying, etc - ... those in zone 8 could keep their bonsai outdoors all season, generally speaking.

Dax
gardener365
15 years ago
What I meant by zone 8 is the pots won't crack and the plants wouldn't need any special protection.

Dax
lucy
15 years ago
Please do not let C. elms almost dry out between waterings! That will kill them as they are not junipers, pines, or maples and can't handle it. Yes you want to cut back on frequency in winter, but that's relative. And don't mist it, it's a waste of time, but if you want to increase humidity get it up on some large pebbles in a wide tray of water. Just don't let the water be as high as the stones or roots could rot.
gardener365
15 years ago
Hi Lucy,

I Thought I was doing some good here.

Take care,

Dax
lucy
15 years ago
Gardener365- Dax, you always do lots of good, but sometimes a particular situation needs tweaking (or disagreeing with), so I put in my 2 c's worth. Feel free to do the same at any time of course!