Thread Graft - Logistical Help

[dbonsaiw]

I plan on trying my hand at some thread grafts in May. The branches I intend to use for the grafts are now in leaf. My question is what can/should I remove from the growth on these branches so that they fit through the drilled holes? I will be doing this on Japanese maples. Obviously, I would cut the leaves off, but what must remain so that it regrows?

On a related note, how much bigger do you make the hole than the thickness of the branch? It seems the hole would need to be considerably larger to accommodate buds passing through unharmed.

 

[Dav4]

I plan on trying my hand at some thread grafts in May. The branches I intend to use for the grafts are now in leaf. My question is what can/should I remove from the growth on these branches so that they fit through the drilled holes? I will be doing this on Japanese maples. Obviously, I would cut the leaves off, but what must remain so that it regrows?

On a related note, how much bigger do you make the hole than the thickness of the branch? It seems the hole would need to be considerably larger to accommodate buds passing through unharmed.

You missed your window. You need to perform thread grafts during the dormant season before bud swell. Your only option, other then to perform approach grafts, is to defoliate the branch (early/mid summer is best timing imo), perform the graft and hope the branch forms buds verses dying. Fwiw, most prepare for thread grafts the season before by allowing branches in appropriate spots to elongate and will even wire them to improve their positioning. When you perform the graft, the hole drilled needs to be big enough that it doesn't damage/rub off the buds as they move through the hole and there isn't really a formula to follow other then trial and error and it'll need to be bigger then you think . I drill the hole with what I hope is the right diameter bit... if the branch passes with minimal resistance, I'm good but if not, I remove the branch and move up to the bigger diameter bit.

 

[Shibui]

Correct that holes need to be large enough for buds to pass through. In practice that means the holes are quite a bit larger than the shoots as mentioned by @Dav4 . That in turn means the shoots fit loose in the holes so we use a piece of stick to wedge the shoot against one side of the hole while it heals and unites.
While on the subject of drilling holes a couple of pointers in case you have not seen them: as the drill bit exits it often breaks out some wood and bark so drill in at the proposed union site to minimize damage where the shoot is expected to unite. Also- drill at low speed so the but does not heat up and cauterize the wood. Starting with a small bit and working up to the size that fits is also good choice to minimize damage and get the best fit.

I've only ever done thread grafts while the trees were dormant so no need to remove leaves.

I guess it will still be successful after leaves but you'll have to defoliate to get the shoots through the holes. Snip leaves off close to the base of the leaf stalk taking care not to damage the buds at the base of each leaf as those are what will grow into new shoots. I've seen mention of wrapping the shoot in parafilm or inside a split drinking straw to hold needles or leaf stems close to the stem so they slide through easier. May be worth trying if there are leaf stems still attached to the grafting shoots.

 

[TomB]

I've tried doing maple thread grafts in the summer, after removing the leaves. Although it is technically possible, it's a poorer choice and it didn't work for me.

You would need to remove the petiole (stalk), cutting as close as you can without damaging the latent buds at the base. Therefore you need a bigger hole at this time of year.

The leaves you remove may not grow back, leading to the branch failing. In my experience maples can be funny about partial defoliation: if you only strip one branch and not the whole tree, it may not push a crop of new leaves but just keep what it has for the rest of the year. Also, defoliating will reduce the vigour of the tree, which is not what you want when grafting.

I'd wait until next year, before the buds swell.

 

[dbonsaiw]

fwiw, my original plan was to attempt grafting next year. Reading over Merrigioli last night he indicated that May is an optimal time to graft Japanese maples (June for tridents). I was left scratching my head as I thought I missed my window. I then started to change my plan to graft this year, which gave rise to a number of logistical issues that everyone pointed out here (which would make early spring the ideal time). I can just as easily wait till next spring.

the wood splintering on the other side is an interesting experience point. When I did wood working the same would happen. Perhaps an angled jig can be made so the entry and exit points can be made to exactly align even when drilling from both sides.
Cauterizing is another issue I didn’t consider. Any use in spraying the tree with water as I drill to prevent this?

 

[dbonsaiw]

Here's an article I found on Bonsai4Me - http://www.bonsai4me.com/AdvTech/ATthreadgrafting.htm - seems to indicate that mid-summer is the best time for this.

Does the calculus change at all if I am grafting from (i) the same tree; (ii) a sapling; or (iii) a branch from an established tree?

 

[Dav4]

Here's an article I found on Bonsai4Me - http://www.bonsai4me.com/AdvTech/ATthreadgrafting.htm - seems to indicate that mid-summer is the best time for this.

Does the calculus change at all if I am grafting from (i) the same tree; (ii) a sapling; or (iii) a branch from an established tree?

I'll disagree with the article and say early spring, before bud swell, is the best time for thread grafting for the reasons mentioned above. Healthy trees grow strongly in spring and most well executed thread grafts on maples will have taken within a few months but certainly within a year. The only way I see a thread graft to be done mid summer is via defoliation which basically stops that branch from growing... at all... for the rest of the year.

 

[Maiden69]

You can use brad point drill bits to minimize blow out and to get a cleaner entrance hole. A set like this DeWalt are a great addition to any tool box. If you want something more rust resistant a set of CrV drill bits like this Fisch would last you a lifetime for bonsai work.

I agree with early spring before the buds swell. That way you can match your exit to your branch as tight as possible without the issue of having buds rub off. I have done ficus during summer, and I used parafilm to protect the terminal buds, while defoliating most of the branch. I don't think I would want to do this with any maple or deciduous tree.

 

[dbonsaiw]

I'll disagree with the article and say early spring

Next spring it is. The advice is much appreciated.

 

[Deep Sea Diver]

Good research! I’d say Harry H really knows what he is doing and likely has done a lot of thread grafting. Can’t see why a professional like HH recommending a practice if it produced a sub optimal result. Yet his posted process is a bit counter intuitive though. It seems to me as it’s six of one, half dozen of the other to one experience in the technique.

I did a spot of research and found practitioners using thread grafting anytime between late winter and midsummer. Yet the safest, easiest bet for a new to the technique practitioner is certainly the late winter as @Dav4 recommends. Don’t see any issues as long as the area is properly sealed.

It looks like HH’s betting on the more immediate summer/fall caliber swelling for the join vs waiting through the branch extension period to have the branch fuse.

Looking forward to seeing your results! Gotta love learning another horticultural tool for one’s toolbox!

cheers
DSD sends

 

[dbonsaiw]

I’m in no rush, so will wait until spring as that seems safest. I’ll be watching my trunk chops for budding. Half have back budded from hard wood and the other half are still bare, but it’s only been a few weeks. If nothing pops by mid May I’ll give the thread graft a go.

 

[Eckhoffw]

I thought this to be a helpful video on the process.

 

[Deep Sea Diver]

THAT’s a great video!

A few very minor quibbles, like why not drill a bit in the branch side after the drilling the pilot hole? Then the entry/exit holes will be both be smooth…

The other is technical, uncovering the cambium on the whip to match the cambium of the trunk on both exit and entry sides? Not needed, yet it might make for a healthier branch…. Maybe overkill?

Thanks for sharing.

Cheers
DSD sends

 

[Shibui]

the wood splintering on the other side is an interesting experience point. When I did wood working the same would happen. Perhaps an angled jig can be made so the entry and exit points can be made to exactly align even when drilling from both sides.
Cauterizing is another issue I didn’t consider. Any use in spraying the tree with water as I drill to prevent this?

You can use any techniques you feel will help but most probably not needed.
Fusion is only required on the 'out' side of the graft because that's where the sap needs to flow from trunk to branch. Sap will not flow from the 'in' side through the trunk and into the branch so fusion on that side is superfluous which also means that bark damage that side is of no consequence.

Drilling at slow speed is far easier than drilling under water and just as effective. Not sure what temps would cause problems or what drill speed will cause that. I just use a low speed and everything is good.

Note that internet posts will only show successful outcome giving the impression that thread grafting is 100%. I've had some failures, as have most people I've talked to who have used this more than a few times, so don't feel bad if the first attempt does not work as planned.

Use this year to grow some suitable shoots for the graft. If inarching from the same tree you need long flexible shoots that will bend round to the graft site without breaking - not as easy as it sounds. I've also pre wired and pre bent shoots which helps overcome this problem.
Prepare a few shoots in case one gets carried away and ends up too thick. Shoots that are growing too fast could be defoliated to reduce thickening.
I've found that shots from lower on the tree graft far better than shoots from higher in the canopy. I guess that's because normal growing direction is upwards and shoots heading down don't grow and thicken as well.

Good luck with the grafting.