Chinese elm queries

[BonsaiLittleMe]

Hi everyone,
I have several queries re chinese elm:
1. I have propagated four or five root cuttings, all in the one planter tray. They are all shooting well. Is now a good time to consider digging them out and potting them on individually?
2. Also with regard to elms generally, here in Perth they are pretty well evergreen. Even though I kept them in the coldest part of the yard over winter, the leaves didn’t fall at all on any of my various elms. Would it be ok to repot and rearrange the roots on them now, or should I still wait until next August?
Any advice welcome!

[BirchMan]

Hi BLM,

I would say the root cuttings would be fine to pot up now - my reasoning is I've just finished doing the same for JRP seedlings last Sunday.

Larger elms, I'd probably wait until August. Unless they're at risk where they are I'd say you've missed the window. They'd probably survive but if you can wait it's better when it's cooler weather and they're more dormant. Agree it's unfortunate we don't get colour in them here but nothing stopping you defoliating them in Winter to get the silhouette.

Cheers
BM

[shibui]

Queensland growers tell me Chinese elm is evergreen up there too. Someone eventually tried repotting with leaves on and that worked fine. I was told they now repot Chinese elm any time of year and the rest of us could probably do that too but we ten to stick with traditional timing.
Small, younger trees are generally OK to repot any time, even if they are growing strongly. I still tend to do mine in late winter but I would be confident you can pot those root cuttings up now if you want to.
Not sure how big or old your other elm is (pics are always good) so guessing a bit but I would say it should cope with repot now if you need to. If there's no urgent reason to I would probably err on the side of caution and wait till August or Sept.

[juan73870]

The above guys are correct, and I can vouch for Chinese elms, at really any stage, being able to handle a repot/root trim/prune/wire, pretty much anything - at any time of the year. I mean, within reason ie. I wouldn't do much except water during extreme heat....
In Adelaide, it is rare for any of my elms to change colour, let alone lose leaves over winter, and I just work on them whenever they need to be worked on.
They're tough as old boots.

[BonsaiLittleMe]

Hi, and thanks everyone for that advice.

I will pot up my root cuttings while we have some cooler days this week, but follow your advice and wait until next August for the larger elms.None of them are in bonsai pots yet- still in grow pots or colanders in the ground.

How tall should I let them grow before chopping them off lower down?
The trunks are only finger thickness, but they are about 1 metre high.

I have been repotting my natives, all grown from tubestock or nursery plants, and growing in colanders in the ground for a year or more. They have all survived so far, despite some drastic work sorting out the roots. I have learned the hard way to sort out the root system sooner rather than later!

[shibui]

There is no set height to grow before cutting back. The theory is that allowing free growth to close to final thickness will give the fastest results but I find that generally results in a vertical, straight trunk with very little taper and a huge cut. It then takes a long time for the cut to heal and new apex to match the stump. Some people are happy with that.
I now prune more regularly. It is hard to tell if that slows growth much if at all but the resulting trunks are usually much better with taper and bends caused by the prune and regrow It also means the earliest cuts have healed and the latest ones are smaller which then heal in a year or 2 and the new apex grows to match the top of the trunk in around the same time. Even if this method slows growth by a year or even 2 that time is then saved in the post growing development stage and quality is way higher
For trees in my grow beds I let them grow free all summer then prune any that are more than 3cm thick or over 1m tall in the winter. First prune is around first branch high - usually about 15cm from the roots. Subsequent chops are at a convenient node just above - about where you plan each successive branch layer. When and where will depend what you want to end up with. Larger bonsai can have larger sections to the trunk and more space between branches. Smaller shohin sized trees need much closer bends and branching so cuts must be closer.

Your experience with natives tallies with many others. Despite the old myths I have found many species to be very tolerant of root pruning at the right time of year. There are still a few species that do not appear to tolerate drastic root pruning. We all need to contribute any accumulated knowledge to a common store. Vic native bonsai club is collecting and storing this sort of data so please contribute any experiences.

[BonsaiLittleMe]

Thanks for all that advice re the elms, much appreciated.

Will take the opportunity also to report as requested re my natives repotting results.

It has now been 3-4 weeks since a group of my trees were root-pruned and repotted. Time I think for them to settle down, and any failures showing up- so far, none (fingers crossed!)
Results so far:

Natives:
Brachychiton: 5 plants that were raised from seed 2 years ago. Stuck in tiny pots for a year and the roots went round and round. Moved to slightly larger pots a year ago and the roots fattened up a lot. This time I drastically pruned and sorted the roots, wired the very flexible stems into all sorts of shapes and repotted into bigger pots. All looking good, maybe one might fail but hanging in there at the moment.

Acacia howittii: a rescue plant from a nursery. Did nothing in a colander for a year. Repotted, trimmed roots. Now shooting strongly. No problem so far.

Syzigium australe “Bush Xmas”: radical root-prune. Now shooting again all over. No problems.

Melaleuca bracteata Gold: roots trimmed and repotted. Shooting again. No problems.

Agonis flexuosa ( WA Peppermint): radical root trim and repot. 5 trees grown from seed two years ago. All re-shooting. No problems so far.

Westringia: another rescue plant I am trying to keep as a shohin. Radical root trim, repot into a small bonsai pot. Looking good, lots of new growth.

Calothamnus hirsutus: moderate root prune. Struggled at first but is shooting on old wood now. Fingers crossed with this one, as it has a lovely spiral trunk twist.

Lepto Riot: moderate root prune. Not happy, might loose this one.

Agonis variagated: moderate root prune. Hanging in there. Will probably survive but taking its time to get going again.

Syzigium “Tiny Trev” moderate root trim and repot. No problems, shooting back well.

Not natives:
Golden duranta: massive root prune. Did not blink! Very strong new growth.

Escallonia: same brutal treatment. Massive regrowth.

Schinus terebinthifolius “Brazilian Pepper Tree”: these trees keep coming up in my garden, now and then I pot them up and grow them on for practice in wiring, clipping, repot techniques etc. Free trees that I don’t care if I kill them. Turns out that is near impossible! I gave two of them radical root-prunes and they just keep powering on- no wonder, since they are a declared weed in some parts. I have another tiny one in a pot the size of a coffee jar lid, still keeps on keeping on....and the compound leaves are staying very small too.

Olive sapling: brutal root trim and repot- no problems, unsurprisingly.

Still more naives to be done over the next month. Will report on them later.