Repotting of a Chinese Elm in Winter

[peh3]

Hope someone can help me out here.
I had a small Chinese Elm outside since summer.
Slip-potted it eventually into a slightly bigger pot and used good subtrate to fill the bigger pot out. So the core is still the bad potting soil from where I got it from.
A few days ago I decided to take the poor thing inside because I doubt it will withstand too much cold like that.
I suppose it was more or less dormant, leaves were kind of red and many fell off.

Now inside I can see buds swelling and starting to open up already.
So my question is very simply:
Can I safely repot it now, as the tree seems to react like it is spring? I want to also clean off the bad soil.
I think now would be a good time, but maybe I am forgetting something? Maybe someone with experience can help me out. Thanks.

Also before someone mentions any of this: I have some neat growing lights to get my plants through winter and I don't plan to keep the elm inside the next winter.

 

[Melospiza]

Since your elm is already indoors, you could either let it keep growing, or try to change the soil. I think changing the soil now is risky since the plant may be weak during the time growing indoors.

That said, Chinese elms can take much more cold (up to USDA zone 5 in some cultivars) than people give credit for, so this elm would have been fine outdoors in zone 7b, as long as the roots are protected by burying the pot in the ground or in mulch (insulation). I would suggest that you leave it outdoors all winter in the future.

 

[peh3]

Well I don't mean to be rude but that isn't really helpful.
I could either leave it be, or try to repot it - I know. It might be risky, hence why I am asking if my logic works here.
Mentioned on purpose that I have good growing lights to provide enough light and that I don't plan on doing this again.

Normally you repot before buds break in spring. Now the buds are swelling on it, like it would in spring.
Hence why I wonder if a good time to repot it would be now, as if it appears to react like it would in spring.
And since the core is still that bad nursery potting soil, I would like to remove it before problems appear.

 

[Joe Dupre']

I think I'd go with the lesser of two evils. Nursery potting soil is not some kind of nuclear waste by-product waiting to instantly kill your tree. The tree has been happily growing in it since it was a seedling. I would put the tree outside and repot at the normal time in spring.

 

[peh3]

Nursery potting soil is not some kind of nuclear waste by-product waiting to instantly kill your tree.

We could argue about this. How do you explain the green glow at night?

Problem is that half holds very little water and the other half holds alot.
It already has buds that are opening and I count two that are starting to extend too. Putting it back in the cold won't work.

I think I will just repot it anyways, if it would be spring this would be the sign to repot now safely.

 

[JoeH]

sounds like you were planning to pot it no matter what was said so not sure the purpose of this thread. A lot of times people overfuss and over think on trees and kill them that way. If its doing fine now I see no reason to mess with it.

 

[discusmike]

The tree was only indoors a few days n budded out? Usually need to be inside much longer then that to start to move,especially if it just went dormant

 

[Leo in N E Illinois]

@peh3
Considering the current state of the tree. Yes, repot now. Bare root it to get rid of the old nursery soil. Then keep it indoors, under lights, until safe to go outside in spring. This will be a test of the quality of your aftercare. If it lives, you have excellent horticultural skills. Chinese elms are best grown as outdoor trees, they are fully winter hardy. But of all the elms, they are one of the few that has been grown indoors, under lights successfully. So give it a try.

 

[peh3]

I did repot it yesterday. I already lost two elms to that nuclear waste by-product soil. I never could get the watering right.
I had slip potted it previously this year into perlite because it seemed to get worse. It gained vigour soon after and did overall pretty well considering the health it was in.
But I realized that getting the watering right with a core of that horrible soil and perlite all around was hard.

When I repotted it yesterday, it was like I thought. I haven't watered it for some time but the soil core was so wet, you could asume I just dunked it in water.
I didn't clean the roots off the soil completely as they seemed to do better than I thought in that muck. But I am sure that the chance of it dying to frost were higher than risking a repot now.

Compared to yesterday a lot of new buds opened up. It might be too soon to celebrate but I'm optimistic.
Here is a picture, but it is hard to capture all the small buds. It gets some direct sun in the morning and after that a very bright lamp activates.


I will report back in a few weeks or months, so that people that found this thread can see how it turned out.

 

[discusmike]

Does not look healthy from the pic

 

[Joe Dupre']

I really hope it makes it. Actually, if it does, we will all have a little better insight as to how much a tree can take. I actually do that with collected seedlings...........transplant, repot and bareroot at different times of the year. I've found that aftercare is perhaps the most important factor to such experiments.

 

[peh3]

Does not look healthy from the pic

How so? Buds are swelling all over the tree everywhere.
Do you think so because of the few leaves? Most turned red-ish and fell off when I had it outside.

 

[peh3]

Seems like all is going well so far. Many of the old leaves fell off however, but I guess that is the new ones pushing them out?

 

[Joe Dupre']

Good to hear! May be why Chinese elms are considered great material for bonsai.

One thing from personal experience. It absolutely amazing how much growth a Chinese elm will put on in one year in the ground, if that's something you are interested in.

 

[Shibui]

In warmer climates Chinese elm just don't go dormant. We have found that they are quite happy to be repotted even when actively growing. Many growers down here now repot late winter, through spring and also fall. Some have even reported good results repotting Chinese elm mid summer.
Repotting time is not as critical as we have been led to believe.

 

[peh3]

As promised, an update.

This is how it did look on the 11th January. It grew well. Even faster than the tropicals I have.


It took too much space on my windowsill, so I cut it back. Which I thought would be no problem since it was growing well under the grow light. However it did not regrow as it would in natural spring and even lost quite some leaves.

This is how it looks today. I put it outside after buds on outside trees started to break and seeds started to grow. Thought it would do it well but it shed off some more leaves and is starting to look sad again. Hoping warmer weather that is bound to come soon will let it recover fully again. Maybe it actually is fooled and thinking winter is coming again?


I'd really like to cut it back hard as it looks hideous now but I'm afraid that it won't be able to take more stress. I probably won't be touching it this year anymore.
And I also wonder what would have been if I had not cut it back in winter. I will update eventually again. Maybe this years growth will be stunted or maybe it actually will still have a headstart.
But I do know that I will not repeat such experiment again. Disrupting its cycle seems to only mean stress. "If it dies, it dies." - That is the mindset that I too have adopted now.

 

[Leo in N E Illinois]

You have proven your indoor horticultural skills to be excellent. I did not expect this tree to be alive. Well done.

In southern Germany, you should be able to grow this species outdoors without having to protect from cold. Just set the pot on the ground, out of the wind and winter sun and it will be fine. Unless you live at elevation above 2500 meters.

 

[Leo in N E Illinois]

There are a few lessons in your experience.
1.) Slip potting is a bad practice. The core soil will always dry out either slower or faster than the new soil. It is far better to do a proper repotting, rather than struggling with a non uniform potting media situation.

2.) Leaves formed indoors will normally drop off when a tree is moved outdoors.

3.) It takes 2 to 3 months for a tree to build up cold tolerance outdoors. It only takes 48 hours at temperatures above 18 C for a tree to begin to loose cold tolerance. Complete loss of winter hardiness can happen in as little as 3 weeks. It is important if one works on a outdoor tree in winter that it is returned to the outdoors as quickly as possible or hardiness will be affected

 

[leatherback]

well done.
I fully expect this to perk up wth a week of nice weather and give another growth spurt. Just give it proper care, which you clearly know how to do.