New Chinese Elm - verifying info & seeking advice

[CliffracerX]

'Tis I again, emerging from my strange little corner of the Tiny Forest to pester y'all wonderful Nuts with some questions & pictures. I recently ordered a beautiful Chinese Elm (Ulmus Parvifolia, specifically) from Kawa No Oka Bonsai to finally fill in the Chinese Elm-shaped hole in my collection.


It arrived today looking gorgeous - even if my weather wasn't!

It's been a little stressed by the transit and lost a few leaves due to shipping, but otherwise is in pretty pristine condition - turgor is pretty high across the board, everything's nice & green, and the whole box had that wonderful smell of chlorophyll hard at work when I opened it. With that in mind, my question now is how best to care for it moving forwards, and to that end I'll be sharing what I've learned so far for y'all to try and take apart if I'm wrong about anything.

1. Dormancy requirements: optional, but recommended once it's acclimated to my environment better.
   • Per my conversations with Jason @ Kawa No Oka, it - and all their other elms - are usually given a dormancy period, but were woken up early this year to get that night, dense flush of spring growth.
   • Additionally, per both the IBC and the wise words of our own nuttiest nut, due to the subtropical nature of Chinese Elms, they have no problems going without a dormancy period, and will instead have quiscence periods, similar to full-tropical trees like ficuses.
   • Worst-case, if I really want it to go dormant but don't want to risk Mountain Weather(tm) zapping it with an unexpected plunge into negative-bajillion F temps, easing it in with some cool outdoors air in the fall & moving it into a mini-fridge is apparently viable.
2. Light requirements: plenty, which I'll be providing with supplemental lighting when indoors.
   • I have both a dedicated plant shelf for tropicals that's got tons of lighting, a decomissioned aerogarden, a surprisingly beefy USB grow light for desk plants, and a fancy lighting setup for an indoors lemon tree, and know my options enough to pick up extra if I need. When it's indoors - and awake (which may end up being a lot of the time, as my outdoors-thumb is browner than a mallsai juniper kept in a windowsill for a year) - it'll have plenty of supplemental lighting.
   • Given the density of the canopy, tiny internodes, and well-reduced leaves, I take ensuring high-quality lighting extra seriously for it - it's clear a lot of work has gone into training and reduction, and I don't want a few weeks of crappy lighting to ruin that with Leggy Syndrome(tm).
3. Watering requirements: fairly bog-standard water-when-dry.
   • The one complication here is in the moss - I've heard conflicting advice on if it's better to remove moss or leave it on, especially for tropicals like this. If it presents no danger to the tree, and won't be too much a pain to care for, I'd likely leave it on 'till a repotting, as it does an incredible job working with the tree itself to sell the idea that this is a big ol' tree providing shade to a field.
   • That said, if it's more advantageous to remove it for the tree's health, I'd likely try and strip it off & grow it separately so I'll have a nice supply of bonsai-ready moss for when I wanna put things on display.
   • Other than that, AFAIK it's pretty standard, watering-wise; wait 'till the soil feels only lightly moist about an inch down, then water thoroughly. I'm guessing based on the minor loss in turgor on the new leaves due to shipping that it's also a fairly 'talkative' tree, and so if I'm not watering it enough it'll probably let me know by getting droopy and sad-looking, same as my Fukien Tea.
4. Future plans: at this point, likely largely maintenance!
   • Being that this is a fairly well-established and trained tree, I suspect it's mostly going to need maintenance work, moving forwards - pruning, cleaning up the branch structure a bit, and general work to keep things nicely reduced.
   • I can't see the full state of the branch structure clearly due to the canopy at present, but I do suspect it might need a little work to clean up & improve density further.
   • I'm also inevitably going to take some cuttings, which I understand to be incredibly easy - pretty much just trim a branch, stick it in the dirt, and forget about it for a year.

All in all, I'm excited about it, moving forwards! I've long wanted a Chinese Elm, and I doubt I could have found a tree that more perfectly fits the dream look than this one.

 

[PA_Penjing]

I like the shape, beats all those mallsai guys.

Everyone has got an opinion, and this only mine but... I find it far easier to treat them like the zone 5 hardy tree that they are. I leave them out in winter just like all my other trees. Of course I protect the pots once the temperature dips below 20 F. Doesn't matter how hardy a tree is the roots don't love dropping into the teens. The two problems with babying chinese elm are 1. They break dormancy earlier than a lot of other trees, so if you give them a wimpy winter they'll probably begin growing even sooner. Maybe this isn't a problem for you if you have a really nice lighting system already. 2. is that trees can get pretty damaged by refrigerators, it is extremely dry inside of one of those things and they can become desiccated.

 

[CliffracerX]

I like the shape, beats all those mallsai guys.

Everyone has got an opinion, and this only mine but... I find it far easier to treat them like the zone 5 hardy tree that they are. I leave them out in winter just like all my other trees. Of course I protect the pots once the temperature dips below 20 F. Doesn't matter how hardy a tree is the roots don't love dropping into the teens. The two problems with babying chinese elm are 1. They break dormancy earlier than a lot of other trees, so if you give them a wimpy winter they'll probably begin growing even sooner. Maybe this isn't a problem for you if you have a really nice lighting system already. 2. is that trees can get pretty damaged by refrigerators, it is extremely dry inside of one of those things and they can become desiccated.

My thoughts exactly! Half the reason I've been searching for so long was trying to avoid the classic Mallsai S-shaped Informal Upright(tm) look that seems to be so commonplace, especially amongst the Chinese Elms being sold here in the states. Weirdly, formal brooms & similar (like this one) are a lot more common in the UK - but it's hardly advisable to ship a tiny tree across the pond like that!

As for treating it hardy - I'd ideally like to give them dormancy for the fact they are hardy trees & it'll be better for its overall healthy growth, but weather here is notoriously weird and unpredictable, so I'm more inclined to try and either treat it fully like a tropical - which I'm definitely able to handle by now, having a growing collection of tropicals on my plant shelf, including the original Fukien Tea from my first thread - or to find ways to give it dormancy without risking one of the infamous 'burg cold flashes zapping those roots to mush. For 1, giving it care indoors if it breaks dormancy earlier than strictly optimal is no big, as I've already outlined. That said, on 2 - the fridge dessication risk is one I'm not 100% sure how I'd get around, and is largely a result of me not having the typical unheated garage of nice cold frame to stick things in overwinter.

 

[Shibui]

Moss will grow on the soil if it is happy with the conditions. If conditions are not right it just dies. Moss can dry out and then come back when moisture returns so just turning a bit brown does not mean death of moss. I'm not sure how moss copes with indoor culture.

Minimum trimming can be simply shear back (hedge trim) to the outline every few weeks as shoots grow out of the canopy through summer.
If you have more time trimming each new shoot individually is better as you can choose where the next bud will grow and hence the direction of the resulting shoot.

Winter, when the tree is bare, is a great time to do structural pruning as it is much easier to see the branching. It would be good to allow the tree to go dormant just for winter pruning if possible. Where leaf drop is not possible defoliation is an alternative though very tedious. Snip off all remaining leaves so you can see the structure for winter pruning.

 

[WNC Bonsai]

I am in the mountains near Asheville not that different from Blacksburg. Mine stays outdoors year round, no babying required—these are temperate trees not tropicals. They can take part sun and do well. I use a freely draining mix and water daily during most of the growing season. In winter it goes into a cluster of other bonsai with oak leaves or pind needles piled on the soil layer. At the arboretum here there is a line of large Chinese elms along the main drive, so they can take it and do well.

 

[rhawes]

I have had zero luck giving my species chinese elm a light winter. I have come to the conclusion they are absolutely outdoor trees from my experience, the other cultivars did fine with a wimp winter but my chinese elm are struggling!!!

 

[CliffracerX]

A disconcerting update on this, one that I was hoping wouldn't come to an SOS on the forums, but sadly my best doesn't seem to be cutting it.
Over the past month or so, it has slowly been shedding its canopy from the inside out - without any other signs of stress, like low turgor or a loss of that healthy leaf shine. A little over a month ago, it looked brilliant:

Of note, I was still keeping it largely indoors - weather was inclement, and I didn't much fancy a sudden freeze burning off all the foliage & atomizing the unprepared root system. As such, it stayed under pretty hefty growth lighting, alongside my pink lemon, while waiting for a more stable season. However, over the course of that month, it would yellow & drop a few leaves every day, starting from the inside and moving out. My initial theory was that it wasn't getting enough light - my Fukien Tea had done much the same, so I tried moving it to live solo under a defunct Aerogarden, which would give it even more light than in its position alongside the lemon. This, in retrospect, may have been a bad move. New growth was already coming out in that iconic sun-baked gradient of lime, yellow, orange, and red, that indicates a happy deciduous getting plenty of light, and once it was under the Aerogarden, some of that growth began to die off - retaining red tips on the yellowing leaves, like a stressed succulent would. Meanwhile, the interior continued to slowly empty.

Last night, being kept up by a Plant Panic Attack(tm), I finally took the moss off to get a look at what's going on under the hood.

Not good! The roots are definitely still intact (i.e, it's not rotting out, just unhappy), but the soil is a mucky mess - the kokodema (spelling?) has clearly broken down a fair bit, and it's probably not getting enough oxygen as such, then leaf burn from being wayyyyyyy too intensely growth-lit is surely not helping.
For reference, the overall state of the tree when I checked the soil last night. Note the yellow and red leaf in the upper left - this is new growth exhibiting the red-tipped stress symptoms I normally associate with the likes of a healthily-stressed Crassula Ovata "Hummel's Sunset", not a semideciduous tree.

If there is one good thing to come of this, it's that I can now at least see the structure of the interior, and it is...not great. If I can pull it out of this mess, I'd definitely appreciate advice on how best to cut back and polish that branch structure into something more befitting of the broom/upright look it could nail.

As it is, I have three theories for what's going wrong.

1. Mucky soil & high water retention drowning the tree.
2. Some burn from being placed so close to the LEDs in the Aerogarden light setup, which while not fatal is definitely not helping matters.
3. Possibly a sign of Moppy Elm Syndrome, as outlined by some other Nuts - when they really get growing, you have to prune hard lest they become a mop and dump the interior of their canopy. This would explain the complete lack of other stress symptoms, and why the defoliation was inside-out, instead of a dieback more typical of stress.

A friend of mine also noted it's possible that it's hungry - while it clearly had some slow-release ferts in the soil, given the state said soil has degraded to I imagine those ferts are similarly spent. That said, I wouldn't dare fertilize while it's otherwise stressed.
With all this in mind, I'd guesstimate the best treatment plan right now is to let that soil dry out a bit, then maybe do a repot into something quick-draining and easy-breathing. Let it recover under more gentle lighting conditions, like one of my smaller lamps, or on a porch. Once it's perked back up and pushing new growth, possibly cut back pretty hard and try to get it backbudding in order to start rebuilding the branch structure and canopy to nail the look.

Any thoughts, Nuts?

 

[Shibui]

Indoor is always difficult for temperate tree species. Changing light conditions is also stressful as leaves need to adjust to changing light conditions each time. Wet soil is definitely not good. Your tree is probably suffering from more than one problem so no point in trying to pin down one.

There's one school of thought that says avoid repotting stressed trees but I firmly believe that if the soil is causing stress then waiting for the tree to recover is futile. Repot to correct soil problems may add a touch more stress but will quickly alleviate the main problem.

You could continue to try to grow it indoors and keep looking for cause and effect or get it out into fresh air and sunshine where Chinese elms definitely do far better.
Fortunately Chinese elm can be cut back hard any time and still bud well so it won't matter if the branches grow longer or more dense while it recovers.

 

[CliffracerX]

Indoor is always difficult for temperate tree species. Changing light conditions is also stressful as leaves need to adjust to changing light conditions each time. Wet soil is definitely not good. Your tree is probably suffering from more than one problem so no point in trying to pin down one.

There's one school of thought that says avoid repotting stressed trees but I firmly believe that if the soil is causing stress then waiting for the tree to recover is futile. Repot to correct soil problems may add a touch more stress but will quickly alleviate the main problem.

You could continue to try to grow it indoors and keep looking for cause and effect or get it out into fresh air and sunshine where Chinese elms definitely do far better.
Fortunately Chinese elm can be cut back hard any time and still bud well so it won't matter if the branches grow longer or more dense while it recovers.

Agreed, on all accounts. My only concerns are going to be with trying to get it out without tearing up the roots too much (especially considering it's probably going to need to be bare-rooted just to really make sure that muck is gone), and in the realm of keeping it happy while it recovers. My track record with stuff outdoors is not great, even with far larger, unstressed & well-established plants, so I'm more than a little nervous about sticking a stressed tree out in the summer's heat!

That being said, any thoughts on a better medium for it to recover in? My instinct says a mix of perlite and something like the BonsaiJack mix - I don't want to go all in on inorganic stuff yet as by my own track record I'm about 99% certain that would be the death of it, but pure Perlite could still leave it in a bad way. A mix should let it retain enough moisture to be healthy, whilst still draining quick and breathing well.

 

[Shibui]

Use whatever mix you are comfortable with. Chinese elm will grow in almost anything but you'll be accustomed to watering properly with one type of mix. It is likely your watering will make a much bigger difference in survival than the type of soil.

My track record with stuff outdoors is not great, even with far larger, unstressed & well-established plants, so I'm more than a little nervous about sticking a stressed tree out in the summer's heat!

With respect, your track record with stuff indoors appears to also be not great.
A few posts ago you were nervous about putting trees outdoors because of cold. Now procrastinating because of heat. Just wondering if you are really meant to grow bonsai?

Seriously though, look for a place with good morning sun and protection from hot afternoon sun but also somewhere you'll be likely to check the tree EVERY day. Get in the habit of checking water EVERY day to combat summer heat. A slightly oversize pot seems to give some insurance against summer dry while you gain confidence and develop good watering habits.
If this one does not survive outside please don't blame the heat. The tree has a lot of different factors against it already, any of which may cause it to give up.

Good luck

 

[rodeolthr]

Ask anyone who puts their ficus benjamina outside during the summer, what happens when they bring it back inside come autumn.......they drop half of their leaves. Talk to the seller and find out what THEIR growing arrangements are for their trees. It's most likely not the same as what you're providing, and the tree is showing its disapproval.

 

[Carol 83]

Ask anyone who puts their ficus benjamina outside during the summer, what happens when they bring it back inside come autumn.......they drop half of their leaves.

Mine don't.

 

[penumbra]

Don't want to come off as too harsh, but forget trying to keep an elm or any other temperate zoned outdoor tree inside. Every year we get a lot of people on this site who come here with dead or dying elms. There are apparently a few people who have kept them indoors, or so I am led to believe by their postings, but an elm doesn't belong inside any more than a maple or oak. And for those who claim to have figured out how to keep an outdoor tree inside, it is all highly doubtful that these plants ever behave naturally or have anything approaching the longevity of a tree outside.
If you want a bonsai inside, get a tropical plant. A ficus is nearly foolproof, but there are a few others as well.

 

[penumbra]

Mine don't.

Do you have a straight benjamini? They do tend to partially defoliate when moved. Most of the benjamini cultivars do not defoliate noticeably. This is based upon the half dozen varieties I am growing.

 

[Katie0317]

Pasting from your post: Not good! The roots are definitely still intact (i.e, it's not rotting out, just unhappy), but the soil is a mucky mess - the kokodema (spelling?) has clearly broken down a fair bit, and it's probably not getting enough oxygen as such, then leaf burn from being wayyyyyyy too intensely growth-lit is surely not helping.
End of paste.

I had to look up kokodema and am confused. What does kokodema have to do with Chinese elm soil? What am I missing?

I'd plant it outdoors in the yard. In dirt. That would be my choice to let it heal. A Chinese elm is hard to kill and it would be a shame to lose the one you got. Planting it in the earth and letting it be a tree for a while and see if it doesn't come around. We have several elms in our yard and they're incredibly hearty.

That's my thought. You can dig it up next spring and start the bonsai process again.

Wishing you and your elm the best.

 

[Carol 83]

Do you have a straight benjamini? They do tend to partially defoliate when moved. Most of the benjamini cultivars do not defoliate noticeably. This is based upon the half dozen varieties I am growing.

Not even sure, whatever is on top of the ginseng thing my brother gave me. My other's are tigerbark, Too Little and Wiandi , none of them lose any leaves.

 

[penumbra]

Not even sure, whatever is on top of the ginseng thing my brother gave me. My other's are tigerbark, Too Little and Wiandi , none of them lose any leaves.

No. none of those do the defoliation dance that the straight species do.

 

[Shibui]

I had to look up kokodema and am confused. What does kokodema have to do with Chinese elm soil? What am I missing?

Akadama.......
It took me a few minutes to decipher.

 

[Katie0317]

I thought he meant akadama too and then I Googled kokodema. He could mean kokodema and not akadama.
You can read about kokodema here.

Kokedama: Lazy-Person’s Bonsai

fifthseasongardening.com

 

[CliffracerX]

Man, this exploded overnight! Getting to the rough messages in order-

I hear the concerns about keeping it indoors, and the message to get it the heck outside. It's been out since the morning after I put up my SOS, currently nestled in alongside my lemon to get it some shade when the worst of the afternoon sun hits. (and for those wondering - no, the lemon has no dreams of being a bonsai, it's just a bushy ol' variegated pink lemon I'm slowly growing out in hopes of one day making into a not so tiny tree to have some funky, fresh-grown lemons in the future.)

Sticking it in the dirt and just letting it be a tree is honestly pretty high up on my options list - my only concern is going to be deer-proofing it while it's in the ground, otherwise it's inevitably going to get one heck of a hard pruning some hungry summer night.

Finally, y'all are right - I somehow mixed up kokodama and akadama! It is decidedly not in a moss-ball, just extremely melted clay-based soil.