Thread Grafting to add lower branch on Chinese Elm

[tmjudd1]

I'm wanting to add a lower branch to this tree, however. This tree does not have any available material for a typical thread graft. I'm considering using a sacrificial 'seedling', in a 2" pot, and basically turning both plants into Siamese Twins, until the graft takes and I later separate them. The trunk thickness, where I'd like to do the thread grafting is about 1/2" in diameter. What would be the largest diameter thread Graft that I could safely install within a trunk this size?

 

[W3rk]

Just thought I'd throw out a couple of options for you. My chinese elm put on a ton of growth over the summer last year. You could let it grow out this coming spring and root some cuttings (I've had great success with this so far) to then use as your grafts. Or you could also see if you can bend any new branch extensions back around to where you want to graft without removing them.

 

[sorce]

Good to graft!

I agree, use cuttings or itself.

If it won't grow big enough to graft to itself.....
It also won't grow to heal the graft!

Fish da dish.

Sorce

 

[Shibui]

Definitely use some material from this tree if you go ahead and graft. Seedlings are all different and this will look really odd if the lower branch has different colored or sized leaves. Stem cuttings of elm are quite easy and root cuttings are even easier so that you will have identical material to graft with.

Most trees do not sprout buds below a healthy canopy. Auxins coming down the trunk from the leaves inhibit buds. To allow buds to grow the auxins need to be stopped/ reduced. Hard pruning is sometimes enough to stimulate lower buds but probably won't help in this case. You could try interfering with the flow of sap at the point you want the buds - a single horizontal cut through the bark will temporarily stop auxin flow below and often buds start just below the cut. The cut heals up in a few weeks so no long term damage, even if the buds don't sprout. I would combine that treatment with a really hard prune up top (I think this one needs a good prune anyway) to double the effect.

What would be the largest diameter thread Graft that I could safely install within a trunk this size?

A hole up to 1/2 the thickness of the trunk should be possible. Thread graft would need to be smaller so the buds will slide through the hole.
Also consider approach graft where you don't need to drill right through.

 

[just.wing.it]

I would air layer instead.

 

[0soyoung]

Just thought I'd throw out a couple of options for you. My chinese elm put on a ton of growth over the summer last year. You could let it grow out this coming spring and root some cuttings (I've had great success with this so far) to then use as your grafts. Or you could also see if you can bend any new branch extensions back around to where you want to graft without removing them.

Easier yet, just keep it attached to the tree - just loop it around and thread it through the hole!

The principle reason one prefers to thread it in spring is that the buds will be smaller and hence the hole in the trunk can be smaller. Secondarily, it is easy to fatally damage the thread when it is actively growing, BUT, one can defoliate the thread, wrap it with a single layer of parafilm to protect its buds and bark. IOW, one can try to affect the graft anytime after a long enough shoot is available.

Another issue is the limit on the size of the hole through the trunk. IMHO, the hole cannot be much larger than roughly one-third the trunk diameter (larger entertains accidental, and possibly very serious, damage to the trunk) - for a half-inch trunk the hole needs to be made with something smaller than a 1/4-inch bit (this would leave about 0.125 inch of trunk on the sides of the hole = risky). My ball park estimates are the thread could then be something like 1/8th to 3/16th of an inch (just ball park estimates). Which is actually fairly thick. Proportionately, thinner stems thicken more than thicker ones. So, I would probably plan to drill a hole with a 1/8th bit, maybe 5/32 to make affect a thread graft on a 1/2-inch trunk.

The tighter the fit, the quicker a thread graft will take.
The tighter the fit, the greater is the risk of damaging the 'scion' when threading it

and wedging it tightly to the top of the hole.​

 

[M. Frary]

Just cut it back hard in the spring to force it to pop buds all over. Chances are you can get a branch to grow where you want it without grafting.
It's an elm for Pete's sake. Not an oak or beech.

 

[tmjudd1]

Lots of good info and food for thought, here. I truly appreciate all the advice. Being as green as I am, I need all the help I can get if I'm going to get off to a good start!

Definitely use some material from this tree if you go ahead and graft. Seedlings are all different and this will look really odd if the lower branch has different colored or sized leaves.

I never thought about that, but it does make perfect sense, now that you mention it! With my limited knowledge, I was simply thinking that a Chinese Elm is a Chinese Elm... is a Chinese Elm!
My main reason for wanting to 'thread graft' a seedling into the trunk was to 'cheat' a little bit. I was wanting to insert a lower 'seedling' branch that already had a bit of girth to it, so it would not 'appear' to be considerably smaller than the next branch up, and would hopefully take on proper proportions within 1 or 2 growing seasons. Not exactly 'instant' bonsai... but darned close to it!

If it won't grow big enough to graft to itself.....
It also won't grow to heal the graft!

Just how much growth should one expect from a Chinese Elm, during one season, provided the tree is truly healthy and all of its needs are properly met?

The principle reason one prefers to thread it in spring is that the buds will be smaller and hence the hole in the trunk can be smaller. Secondarily, it is easy to fatally damage the thread when it is actively growing, BUT, one can defoliate the thread, wrap it with a single layer of parafilm to protect its buds and bark. IOW, one can try to affect the graft anytime after a long enough shoot is available.

I either read, or watched a video (don't remember which) where it was being proposed that thread grafts were better performed in winter, while the tree was somewhat dormant. Didn't explain why. Would your statement be on those same lines, possibly to protect/acclimate the thread, somehow, prior to entering the next active growing season? In addition. I was also thinking of the buds when I thought about using a large diameter seedling. I can actually bore a tapered hole in the trunk that would be the same size and shape of the scion, where I want it to seat into the trunk, that would be larger in diameter than the majority of the length of the whip. All buds would be fairly safe except for the ones at the base of my whip, where the whip starts to seat tightly into the trunk. I'll not want any secondary branches in that area, anyway, after the branch is well established. I hope that makes sense. Basically, I'd be inserting a long, long cone into a precisely tapered hole. "Machinist Bonsai!"

 

[M. Frary]

within 1 or 2 growing seasons

A branch from a bud will be filthy in one year if let grow freely.

 

[sorce]

Just how much growth

I had a Siberian elm seed root in half a pond basket and hit almost an inch thick with branches on branches on a trunk by the end of the year.

Filthy! Lol!

Took me about 5 years to get good growth on things and realize what it was.

Sorce

 

[M. Frary]

Filthy! Lol!

I dont know where that came from except I did watch Home Alone recently.
"And keep the change you filthy animal"

 

[tmjudd1]

A branch from a bud will be filthy in one year if let grow freely.

I'm now starting to see what you meant by 'Filthy'! My true growing season is currently just 'starting' to begin, and in such... this 'thing' is already going nuts! It's starting to give me 'flashbacks' of a high maintenance girlfriend that I once had to deal with, many moons ago! Unlike 'her', I think I will keep the Chinese Elm!