Zelkova Serrata

Arising from the very inspiring exhibits at the Exmouth show, I was especially interested in that Zelkova and Marcus' defoliation - the 6 hour job. Having just acquired a couple of these, and repotted them from the mess they were in, would it be right to defoliate them in say, two months, or should I wait for next year? They certainly could do with the light getting in to the inner branching, but I don't want too much trauma for them too soon.
Advice please?

When you say " repotted " did you cut any roots.
If you haven't then you should be ok.
Perhaps a better option would be to just remove the larger leaves first.

Thanks Peter. Lightly trimmed roots before repotting - very lightly. But Zelkovas make rapid progress if they are treated well, don't they? I thought 2 months on would be OK, but may not be worth the risk.

Hi Rick,

glad you enjoyed the show. A tree repotted in april definitely can be defoliated now, in fact it is essential as the added vigour following potting will lead to big leaves and powerfull straight shoots.

I have several zelkovas here and they are one of the fastest growing trees I've worked with - i defoliated one of the others 3 weeks ago and it had new leaves showing within a week - My good one was done 6 days ago and the first new buds opened 2 days ago in the canopy, by last night the buds were swelling all the way down to the lowest branches. The reason it works so well seems to be that a single leaf is removed and the new bud makes a fine twig with 2 or 3 leaves so outer ramification forms quite easily. It was essential to gain as much accurate information about the tree from professional growers and people I know with exceptional examples before taking on such a special specimen and "defoliate at least once a year", "feed very well" and "sun loving" were all stressed.

The second reason I have to do this tree is to let those inner shoots see some light for a few weeks so they survive and continue to build the broom from the inside, The inner shoots were not defoliated as I want them to gain strength and grow rather than form more tiny twigs that would only die back once the canopy returns. In time many parts of the outer tree will be pruned back to inner twigs as the branches thicken and lose visual taper so the inside shoots are the future of the tree.

the feed well advice is important - so many growers under feed all their trees and they hold back even more on fast growers - I hear supposedly experienced bonsai people advising sparse minimal feeding of tridents & zelkovas due to large leaves forming and long nodes when it is the opposite that is required - tridents need 2 defoliations per year - i usually do one full and the second on the outer canopy - plus pruning of course. When you ask a tree to give you a lot of development you need to give it the food to respond and not starve it into weak stunted growth - the under feeders usually lose a tree or two each winter which proves the point really - bonsai dont die very often at random - usually the owner has a big part to play !
I think that keeping the zelkova the same way as the trident will go a long way to improving and maintaining great ramification and health



Monday 24th June 8pm ish

cheers Marcus

i actually repotted and defoliated the little one same day - the one that was leafing out in a week - we know a tree with swelling buds will recover root growth quickly following root pruning - i wonder if we could create a new repotting window for healthy vigorous deciduous trees by defoliating them a week or so before a summer repot ? if it works it takes away the annoyance of poor spring weather following early repotting

time to forget the old rules and do some experimenting i think  - i'll play with some small tridents, zelkovas and chinese elms to see what happens - this is just my cogs turning atm so i wouldn't rush out and try it on a good tree just yet - the more i think about it this could be a brilliant way to control the strong new growth of the second flush you get on a defoliated trident.

cheers M

Morning Marcus. Thankyou for the information and reasoning. I didn't actually go to Exmouth, but the pics were enough to see what had gone in and on! These two Zelkovas of mine are the first time I've tried the species, so I'm especially keen to get it right. Your help is invaluable.
What size can Zelkova be grown to as a bonsai? Most I have seen are shohin or not much bigger, and they are credible like that, but does it work for larger specimens as well? What size was the one you defoliated (shown in this thread)?
Do you have a view on which deciduous trees should NOT be defoliated? Cheers. Rick.

BTW - Your logic sounds good to me, but I'll leave the experimenting to you!! I'm nowhere near experienced enough for that. Cheers.

Zelkovas make superb bonsai of all sizes and its fair to say the only reason we don't actually see any good big ones yet is simply because they are not selected for import by European buyers. I have borrowed a couple of pictures from online blogs of large brooms - one very well known tree and one i'd not seen before - there is a bigger one too of extremely high quality - the picture includes a young Russian apprentice behind the tree but i cant find it yet





My tree is 48cm tall, 50cm wide so chuhin sized or 'medium' bonsai

I'm begining to learn we (as in non japanese) bonsai growers tend to avoid or ignore defoliation wherever possible where-as the japanese growers use it as part of the standard annual techniques to aid refinement of many trees. I know there is older information saying to avoid annual defoliation but many trees if well fed respond excellently. Using the method for the right reasons is the key - it triggers inner buds to form or triggers dormant inner buds to open so it increases the density inside the tree. Partial defoliation of the outer canopy is used to let light in so weak inner shoots can strengthen and it will trigger buds in the outer areas to open...this increases inner strength and outer ramification. Lastly leaf reduction of the outer canopy (different to defoliation) is used to just let light in to the inner shoots but not to trigger new buds to open. trees at different stages need different methods

it will be interesting to see which trees readers have good and bad experiences with.
My 1st hand experience so far
Total defoliation good with acer palmatums including deshojo / kiyohime / mikawa, Trident maple, Field maple, Sycamore, Chinese Elm - cork and normal, Zelkova serrata, hornbeam (but leave end leaf in place), cotoneaster, firethorn, buddlea, various prunus. inner buds open soon after

not good with japanese white bark beech - crenata. the tree just sat for the rest of the year with buds but didn't open them until the next spring - reduction of leaf size by cutting it in half works very well though to let light in to inner shoots

I've not tried European beech, hawthorn, blackthorn

Thanks again, Marcus, for the detailed info. It's a bit of an eye-opener - I did not realise that it was another one of those contentious things. As you say, other's experiences may differ.
One on your success list makes life even more complicated - for me, at least. My Firethorn (Pyracantha) is just coming into flower, so defoliation would have to be done earlier than midsummer, or maybe not? Perhaps it is unaffected by the formation of flowers? So much to learn - so little time! Cheers. Rick.

Hi

I recently bought a 3.5m tall Zelkova, couldn't believe I would ever find one in the local nurseries - bit of a dream come true  

This tree will be an exercise in patients since I have to air-layer my way down over the next few years and get as many trees as possible out of this.

But I have to ask, I read somewhere (old forum post) that Zelkova air-layers don't survive their first dormancy.......? Any truth to this?

Thanks for the advice and examples, seeing these trees gave me a warm feeling all over.....  

Cheers
Gerhard

Hi,

firethorn defoliation - if you have straight branches with no side shoots - ie lack of ramification i would go for a year with no flowers and berries and defoliate the tree early summer, prune the tip of the long branches as well and let new shoots develop. this is a great time to wire if you need to as well. David has an awesome thread on here with a very nice firethorn - I know he cuts back very very hard at times from the pics so not many leaves remain - then look at the flowers next year !!!    

Re air layers - lots of large sized airlayers do not survive the first winter regardless of species as people cut them off too soon - if you have lots of foliage above it will need lots of roots to support it so 2 summers may be best before detaching. I would also feed the layer area once hardened roots are forming or it will be deficient in essential items

cheers Marrcus

Hi Marcus

I've been going through the same process with a Chinese Elm the last few years, so I'm pretty confident I can find the balance. I lost about 20cm of the trunk on the parent tree after taking off the last layer, but otherwise 2 thriving layers already.
From what I read the Zelkova is not quite as tough as the Ulmus, so I'll keep that in mind

Thanks

Again - thankyou Marcus. I'll be sure to look it up and follow the experienced advice. Cheers. Rick.

hi,
i think in the league table of hardy air layers chinese elm, juniper chinensis and acer palmatum/ trident lead the rest - these have never failed on me !!! (that has now tempted fate big style !!!) if a tree is suspected of being less hardy i would have an 18 month plan with winter protection built in - that should make it easier

cheers Marcus

Marcus - Following your posts on this thread I took your advice and launched straight into defoliation of one of the Zelkovas 10 days after repotting. The results are excellent! 2/3 weeks on and there is new growth everywhere, with no apparent damage to any part of the tree. Now I have to ask - when to recommence feeding? Thanks for your time. Cheers. Rick.