Elm Wintering

[Duhend]

Hello everyone, I'm new to the forums, not to bonsai although I am new to the world of Elms. This is my first deciduous bonsai so I am lacking in the wintering knowledge. I'm in the great State of Kansas in Lawrence and my heartiness zone is 5B, and I'm wondering how I need to winter my Elm.

The pot itself says it is a Zelkova, and from the threads I'm fairly sure its what I have. The lady from Earl May, where we got it on a whim didn't know much other than the bonsai stock they received came from a grower in Florida. I got it in August and it has been growing like a weed ever since, it lives outside as it should. We've had a few 30 degree mornings, but not much less than that so I've expected to see some leaf drop but I haven't. I'm a bit worried that it may still be in Florida mode, so that's why I've come here for advice. I have noticed some leaves turning yellow, which could be good, but I'm also worried that it isn't ready for a Kansas winter and it may start to die on me.

I've read places to pot the plant in its pot in another pot, I suppose more dirt protects the root mass. I've read to stick the pot in another pot with mulch, which sounds odd. I've also read just to put mulch around the pot to help protect it. Other than making some sort of wintering glass box are there any ideas on what I should do? I was going to winter it in my foyer to my apartment building because I knew it would get cold but not below freezing but that went out the window with a vent I discovered. I was thinking a garage as well, which is feasible. I would however like to enjoy it leafless and keep it at my apartment, that is half the beauty.

So I thank you all in advance, I'm sure I've rambled far to long, but I find more info is better than not enough info. I'm off to investigate more into in this section of the forum.

 

[JudyB]

You say you are in Kansas, what zone, and what is your snow and wind conditions like there? All these will factor into what type of protection you will need. You could do a unheated garage, that is usually good enough for elms.

 

[Duhend]

I live in 5B. We don't get too much snow, maybe 3ft total all winter, it just depends. As for wind where I am at isn't too bad, the plant as it sits just gets south wind, no northern cold wind. My place isn't too windy, the apartment building blocks it pretty well.

 

[JudyB]

5b would be fine for an elm if you were to bury the pot and mulch it outside. But in a shady location, and out of the wind. It will also be just fine in the unheated garage. Since it is from a warm climate, you might want to go with the garage this year to temper it's first winter. They do want a dormant period, so I wouldn't suggest keeping it inside your house, although most chinese elms will pull thru one winter inside. However this may be zelkova as you said, and I don't know if it would be ok even for one winter. Repeated inside winters on Chinese elm will drain the plant and eventually kill it.

 

[jk_lewis]

If this is an elm from Florida it will need a good deal of winter protection. No matter the species, the genetics of Florida trees will NOT let it do well in a Kansas winter.

 

[Poink88]

If this is an elm from Florida it will need a good deal of winter protection. No matter the species, the genetics of Florida trees will NOT let it do well in a Kansas winter.

I agree. However, note that a lot of Florida nurseries (and all other nurseries nationwide) import trees. It could very well came from a northern state (relative to Florida)...or very likely China from the looks of it

 

[Duhend]

I was leaning more towards the garage this year anyway just because who knows what kind of life it had prior. So I'm assuming mulching is the preferred method of wintering then? I've never kept anything all winter that needed a dormancy! I always spent the spring begrudgingly helping mother replant things lol. I'm still a bit worried because I've got leaves still and its November but its still 60 degrees in the day. I guess I will wait to garage it til the leaves drop or its constantly below freezing every night. It's been hovering around 36 at night lately.

As far as where its from the lady didn't seem to know much but I can't figure where it came from wouldn't give it a dormancy I'm hoping it was an import but who knows these days. Thanks again for the input.

 

[Stan Kengai]

Duhend, Your plant needs to be outside for a few frosts. It will be fine unprotected to about 25 degrees overnight. Bring the plant in once the daily lows are consistently in the upper 20s.

 

[Brian Van Fleet]

Welcome. The label correctly identifies it as Ulmus parviflora, which is commonly called Chinese Elm. It is not a Zelkova, which is a different genus within the Ulmus family.

U. parviflora is a temperate zone tree, not predictably hardy below zone 6 in the ground; and they're less hardy in a pot. The roots should not be allowed to freeze. A garage would work for overwintering, if it stays above freezing all the time, mulched in using pine straw or bark chips.

It can also be treated like a tropical tree, if you have the setup necessary (which entails more than a sunny window). Indoors, it will require more attention, care, and constant defense against dry air, pests, fungal attacks, and a winter-long roller-coaster of losing leaves, growing new weak shoots...etc.

 

[Duhend]

Well the label is another issue. It says its a Zelkova and then states that its an U. parviflora. So I think they mean for it to have an identity crisis. I thought the leaves looked like parviflora, but the bark didn't fit the bill, so I snooped a round the forum more and found Zelkova leaves that were similar as well as similar bark. Well now it would seem I have a decision to make...

 

[rockm]

You can't force dormancy with low temps. Your plant is refusing to drop its leaves because it hasn't been "told" to. Temperature plays a minimal roll in the dormancy of deciduous temperate trees. Dormancy is induced by shortening day lengths.

If your tree has been kept in a greenhouse or indoors before you got it, it hasn't been exposed to the shortening days that begin in June. Shorter days induce hormone changes in the tree that tell it to begin storing nutrients for the coming winter. The process is very gradual and begins happening in June. Leaf drop is one of the final stages in the process.

All this means, if you plunk the plant out in the cold now, you're more likely to just shock it and if the temp gets low enough, kill it.

If it were mine, I'd just bring it inside for the winter and have it limp through til spring, then once temperatures have reliably risen above freezing, put it outside and leave it there.

Ulmus parvifolia is quite capable of handling freezing temps to well below 20 F. They're common street trees here in Virginia.

I've kept my U.Parvifolia bonsai outside mulched under cover for years. Air temperatures have dropped as low as 0 F on a few winter nights, but average around 35 or so at night in an average winter.

 

[Duhend]

I'm honestly not sure how long it was kept indoors, I'm hoping only for the short period of time to sell it. I'd hope the grower knew to keep it outside but you never know when it comes to mass production.

 

[rockm]

"I think they mean for it to have an identity crisis. I thought the leaves looked like parviflora, but the bark didn't fit the bill, so I snooped a round the forum more and found Zelkova leaves that were similar as well as similar bark. Well now it would seem I have a decision to make... "

They do intend an identity crisis, but only to skirt importation law. This is a chinese elm (ulmus parvifolia) and definitely imported from China. Imported Ulmus Parvifolia are often intentionally misabeled or identified in confusing terms in their originating port in China to get them past US importation restrictions. Chinese elms are proven vectors for many destructive insect pests from abroad, particularly the Asian Longhorn beetle. The restrictions on Zelkova are less strict.

Imported Chinese elm bonsai have been documented by border agencies with carrying that pest, which could do tremendous damage to U.S. forests.

IT IS NOT A ZELKOVA. The leaves AND bark definitely fit Chinese elm.

Zelkova leaves are strikingly different than this, being longer, bigger and lance shaped. I have both Zelkova and chinese elm.

FWIW, the "grower" you bought this from was only a middle man. It is VERY unlikely he/she kept it more than six months and it was probably kept inside during that time. Also before tht, it probably traveled tightly packed in a crate with hundreds of others like it for months on a boat.

 

[Brian Van Fleet]

Here is a side by side. The left (in both images) is Chinese Elm, U.parviflora. The right is Zelkova, Z. serrata. Note, the parviflora is in the ground, so the leaves are a bit larger than a containerized counterpart.

 

[Duhend]

The pictures defiantly help, I picked up a new book today as well which has good pictures as well. I think I will stick to the forum and books from now on, the internets have so much contradictory info. So my next question, since you think I need to bring it in is when should I do so? Its been in the upper 30's at night and in the 60's during the day. I suppose I will have to find a good spot away from Mac the bonsai munching cat as well.

 

[Brian Van Fleet]

The pictures defiantly help, I picked up a new book today as well which has good pictures as well. I think I will stick to the forum and books from now on, the internets have so much contradictory info. So my next question, since you think I need to bring it in is when should I do so? Its been in the upper 30's at night and in the 60's during the day. I suppose I will have to find a good spot away from Mac the bonsai munching cat as well.

Bring it in before it freezes.

 

[AaronThomas]

Baby it cold outside....

Hey all... Not to hijack the thread or anything but my question fall under the "wintering" category as well.
Were going to be seeing some pretty cold temps here in Tucson over the next week or so... Highs in the upper 40's and lows in the lower 20's and high teens. I've been covering my Chinese Elms at night to protect from some of the hard frosts we have been getting but with the low temps which are in the mail and my trees aren't use to... I thought putting them in the garage where the temps are around 50 to 55 in the day and around 40 at night. Just wondering if that is a wise decision. Thanks! Hope your all have a great start to the new year!

 

[rockm]

putting them in the garage couldn't hurt...

 

[JudyB]

Hey all... Not to hijack the thread or anything but my question fall under the "wintering" category as well.
Were going to be seeing some pretty cold temps here in Tucson over the next week or so... Highs in the upper 40's and lows in the lower 20's and high teens. I've been covering my Chinese Elms at night to protect from some of the hard frosts we have been getting but with the low temps which are in the mail and my trees aren't use to... I thought putting them in the garage where the temps are around 50 to 55 in the day and around 40 at night. Just wondering if that is a wise decision. Thanks! Hope your all have a great start to the new year!

I always go with better safe than sorry. If there are significantly different conditions than you've had before, I would move them into the garage. The only problem with moving them into slightly better (warmer) temps, is when it gets too warm. Sounds like 50 during the day for the period of your cold snap will not be a problem, as the temp goes down at night. And less fluctuation is better if you can achieve it by keeping the doors closed during the day and trapping any cooler air by opening between sunset and evening.
Just how I would do it, I'm sure there are lots of opinions out there...

 

[AaronThomas]

Excellent! Thanks Judy and Rock for your replys.