Looking for ideas to thicken Chinese elm trunk bottom.

[fredman]

I've been growing this from a stick in a pot....some 15 yrs.
Its coming on nicely lately...but it has a major flaw. Above the nebari, the trunk is "flat".
I obviously should've paid better attention when it was growing in the ground...but that's spilled milk now.
Any ideas as to how to correct this now...?
I'm thinking maybe place a thread graft (from a big pot...or even plant the root section in ground) in the narrow area, let it grow out to fatten up the bottom section....

 

[Shibui]

Healing damage usually adds thickness quicker than normal growth so damaging the trunk where you want extra thickness can help.
I've seen 2 methods used:
1. lightly hammer the bark repeatedly where you want it to thicken. Need to hit hard enough to cause some cambium damage but not too hard to cause permanent problems?
2. Make vertical cuts through the bark in the area that needs extra. I've used this method. It did take a few years to make much difference but repeated cuts a couple of times each year did work.

 

[fredman]

Hahaha...I forgot about that. I've actually done that to a tree (forgotten which one)....waaay back in the beginning.
Yeah that's the answer.....Thanks mate..
I'll get my carpentry box out.

 

[oranjeaap]

Because I like the tree better on the first picture anyway I'd say rotate it 90 degrees in the pot and problem solved!

 

[Shibui]

Because I like the tree better on the first picture anyway I'd say rotate it 90 degrees in the pot and problem solved!

Great remedy for the trunk but then the branches do not grow in suitable directions so, while you may be solving one problem, you are creating another problem.

 

[fredman]

Because I like the tree better on the first picture anyway I'd say rotate it 90 degrees in the pot and problem solved!

Great remedy for the trunk but then the branches do not grow in suitable directions so, while you may be solving one problem, you are creating another problem.

Haha...I just want it to look good from all sides.

 

[MACH5]

My method is to puncture the bark with a pair of scissors or similar sharp tool. I make many small incisions in the desired area. Should be done more than once within the same growing season. But as with many bonsai techniques it will take a while to take effect.

 

[rockm]

FWIW I’ve found the hammer method shortcut very unreliable and produces odd looking swelling that doesn’t really look like maturity. Same for slicing through the cambium. This is an elm. You can get natural looking results in a couple of years simply by planting it out inthe ground or planting it in a lever grow bow with tile underneath the root mass. Both will produce better looking results without odd looking lumps and ridges (not to mention to danger of hammering the side of your tree to death or God forbid girdling the tree with callus tissue).

 

[fredman]

Thanks people. I have a plan of action. I'll make incisions with the scalpel and drill some 1mm holes.
@rockm I've considered planting it, but it has spent a lot of time in there already. I don't want to loose the bit of ramification it has already.

 

[Ply]

My method is to puncture the bark with a pair of scissors or similar sharp tool. I make many small incisions in the desired area. Should be done more than once within the same growing season. But as with many bonsai techniques it will take a while to take effect.

This is the thread @MACH5 was referring to, for anybody interested.

I distinctly remember the thread as it's the only succesful instance of scarring that I've personally seen. I think it's best used for subtle areas to combat reverse taper (or lack of taper, in this case) - rather than overall thickness of trunk. If I hadn't seen Mach do it I would've considered it makebelieve. But it's a tool I'll gladly add to my arsenal.

 

[penumbra]

Great remedy for the trunk but then the branches do not grow in suitable directions so, while you may be solving one problem, you are creating another problem.

Because I like the tree better on the first picture anyway I'd say rotate it 90 degrees in the pot and problem solved!

I also think the tree looks much better in the first picture.

 

[fredman]

Question to be sure plz...
Which time would be optimum to scar the cambium...?
I'm thinking it needs quite a lot of bulging to rectify the narrow section. If I scar it early spring when it buds, it'll push maximum energy in there...but it might create excessive bulging, and I want progressive growth over the entire area.
But, if I do it after the spring flush, it will bulge slower...but that will take longer.
I have to add...this tree is a slow grower since its been potted. Every year it hardly grows a second flush...after I trimmed it in summer time.
With that in mind...I think i'll do it early spring...?

 

[Shibui]

Not enough experience to know whether timing makes a difference.
I'd be inclined to just work on the outside of the curve. Thickening inside the curve will straighten the trunk. Thickening outside should give you a little more trunk movement down low.

 

[fredman]

Makes sense yes...thanks mate.
I just read on the link above that Sergio said its not a one time thing....it should be done throughout the season. Makes sense to me to.
It obviously also will depend on the reaction from the tree...and will differ from tree to tree.
I'll see how it responds and go with it accordingly. Logic says not to over do it. Give the bark time to properly recover before attacking it again....

 

[Shibui]

Logic says not to over do it. Give the bark time to properly recover before attacking it again

This is how I did the trident maples I tried it on. Also did it several times each season. Seemed to take several years to have any real effect.