Thread graft question

[willhopper]

When a thread graft is done, does the cambium fuse on both sides or just the exit side? The reason I ask is, when I was drilling through, the bit was laboring and when it finally went through it did so quickly and the chuck ended up hitting the trunk, making a larger ring around the hole.

So, the cambium might not make it down to the scion on the exit side before it starts to roll over and heal. The entry side is very snug.

Am I screwed?

 

[Brian Van Fleet]

When making a thread graft, you should always drill in the opposite direction as the thread graft. However, in this case, you may have gotten lucky. The exit side is where you want the graft to knit, and the entry side should just heal.

 

[willhopper]

When making a thread graft, you should always drill in the opposite direction as the thread graft. However, in this case, you may have gotten lucky. The exit side is where you want the graft to knit, and the entry side should just heal.

Thanks, but I did drill it that way. The chuck hit the tree where the Scion exits. What you are seeing is the scion coming out, not going in.

 

[willhopper]

When making a thread graft, you should always drill in the opposite direction as the thread graft. However, in this case, you may have gotten lucky. The exit side is where you want the graft to knit, and the entry side should just heal.

Maybe we should be more clear with entry-exit. So are you saying the exit side of the scion is where you want it to graft, because that’s where the large wound is and what I have been asking? Or the exit side of the drill bit?

 

[0soyoung]

One can apply a wire tourniquet on the input side to make it swell and potentially 'take' before the exit side has. While it does make the input side 'heal over' much faster, it completely removes your ability to judge the success of the graft by the differences in the thread stem thickness of the exit side versus input. not the question you were asking.

 

[Smoke]

You want it snug on the exit side. Just take the whip out, seal both holes inserting a stick of the same size in the hole, cutting flush and seal the holes. Then do the hole drilling process 1/2 inch from where you screwed up. Be more careful this time!!!

 

[Lou T]

You want it snug on the exit side. Just take the whip out, seal both holes inserting a stick of the same size in the hole, cutting flush and seal the holes. Then do the hole drilling process 1/2 inch from where you screwed up. Be more careful this time!!!

So in effect he’d be creating a patch?

 

[Brian Van Fleet]

Thanks, but I did drill it that way. The chuck hit the tree where the Scion exits. What you are seeing is the scion coming out, not going in.

If that’s the case, you drilled it the right direction, just sloppy. If your thread graft enters from the left side, and exits on the right, your drill bit enters from the right, exiting on the left. The clean side is where the bit enters, and the scion exits. However, it appears you have damaged the side where the scion exits, so I’d probably redo it as Al suggested, unless you’re working with a really fast-growing species like a ficus.

You should also try to have the first node closer to the trunk than you got, otherwise you’re always going to have a long distance between the trunk and first bifurcation

 

[Smoke]

So in effect he’d be creating a patch?

Sure.... will heal in a month. More like a band aid

 

[willhopper]

You want it snug on the exit side. Just take the whip out, seal both holes inserting a stick of the same size in the hole, cutting flush and seal the holes. Then do the hole drilling process 1/2 inch from where you screwed up. Be more careful this time!!!

This is what I did. I determined that it would be the side I screwed up that would need to graft, so I plugged the hole with putty and sealed it with cut paste. Drilled a half inch away and did it again and it’s went flawlessly. Fingers crossed.

 

[willhopper]

If that’s the case, you drilled it the right direction, just sloppy. If your thread graft enters from the left side, and exits on the right, your drill bit enters from the right, exiting on the left. The clean side is where the bit enters, and the scion exits. However, it appears you have damaged the side where the scion exits, so I’d probably redo it as Al suggested, unless you’re working with a really fast-growing species like a ficus.

You should also try to have the first node closer to the trunk than you got, otherwise you’re always going to have a long distance between the trunk and first bifurcation

Thanks, yeah, I’ve read that before about the first node. I hope I did it close enough.

 

[peterbone]

I my opinion you could leave the thread graft as it is and seal over the damaged area. I think it will easily be able to heal over the wound and still fuse. If it doesn't then you can always redo it still later.

 

[Shibui]

I my opinion you could leave the thread graft as it is and seal over the damaged area. I think it will easily be able to heal over the wound and still fuse.

I agree with this. The cambium is growing underneath as the tree 'rolls over and heals' so the damaged area will still graft, just takes a few weeks longer.
Both sides (entry and exit) of the graft can unite. I have had some instances where only the entry side healed successfully and I had a branch feeding nutrients back to the trunk - not really what was intended.

I can't see any sign of bark removed from the scion in the photo. Normally I would scrape a little area where the scion exits the hole so there will be exposed cambium on both parts. This makes uniting quicker. If the scion is intact it can still unite but the bark will prevent cambium contact until the scion thickens quite a bit.

Also interested that the

The entry side is very snug.

I've always needed to drill oversize holes to allow the buds to slide through because buds are nearly always wider than the shoot. Never been able to get a 'snug' fit on a thread graft. Where the hole needs to be larger to allow buds through a wedge of some sort is used to push the scion closer to the side of the hole, especially when bark has been removed on the scion.

 

[willhopper]

I agree with this. The cambium is growing underneath as the tree 'rolls over and heals' so the damaged area will still graft, just takes a few weeks longer.
Both sides (entry and exit) of the graft can unite. I have had some instances where only the entry side healed successfully and I had a branch feeding nutrients back to the trunk - not really what was intended.

I can't see any sign of bark removed from the scion in the photo. Normally I would scrape a little area where the scion exits the hole so there will be exposed cambium on both parts. This makes uniting quicker. If the scion is intact it can still unite but the bark will prevent cambium contact until the scion thickens quite a bit.

Also interested that the

I've always needed to drill oversize holes to allow the buds to slide through because buds are nearly always wider than the shoot. Never been able to get a 'snug' fit on a thread graft. Where the hole needs to be larger to allow buds through a wedge of some sort is used to push the scion closer to the side of the hole, especially when bark has been removed on the scion.

Thanks for replying. As you can see in the photo, the amount of cambium accidentally removed in the circumference Of the exit hole likely would have been a bridge too far to cross. It would have taken far too long to reach the scion, IMO, and I didn’t want to lose that time or run the risk of it not fusing at all.

As for the scratching of the scion’s cambium, everything I’ve researched says not to do that. This isn’t an approach graft. The scion has no choice but to grow so it will be forced to fuse, and this way I’m not inviting any pests or fungus, etc., to infect the scion.

 

[willhopper]

Well, the thread graft was doing well, but now for some reason the leaves on the out side are dying off and the branch seems to be dying back. The IN side is great, healthy and has great new happy leaves. I have no idea what’s going on

 

[0soyoung]

The xylem in the thread is clogged (CODIT reaction to some kind of damage). Usually this comes from scraping the cambium (accidentally/intentionally) which could have happened when threading or by over tapping the binding shim (the toothpick/skewer tapped into the hole to hold the thread snugly against the top). It is also possible that it was cracked in bending the thread to feed into the hole.

Wait until bud break to be certain it is a dead end.

 

[willhopper]

The xylem in the thread is clogged (CODIT reaction to some kind of damage). Usually this comes from scraping the cambium (accidentally/intentionally) which could have happened when threading or by over tapping the binding shim (the toothpick/skewer tapped into the hole to hold the thread snugly against the top). It is also possible that it was cracked in bending the thread to feed into the hole.

Wait until bud break to be certain it is a dead end.

Thanks, it definitely is dying back, the branch has turned black at the end until the midway point.

 

[Paulpash]

If it was really tight threading it through the stem can sometimes buckle.

Silly question but did you check that all the buds were in tact after you had guided it through the hole?

 

[willhopper]

Yes, but wondering now if it was too tight in the hole. And wondering if the terminal bud fell off later.

 

[thumblessprimate1]

Sometimes I drive a stick or wire of similar thickness through to make sure no debris is left to hinder the thread. It also helps prevent damage of buds when the hole drilled might be too small for the thread.