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Thread Grafting

10 years 1 month ago - 10 years 1 month ago #17091 by Taffy
Thread Grafting

Thread Grafting is a method of placing a branch where one is needed. Some trees don’t ‘back bud’ very well, and this procedure can overcome that shortcoming.

One of the advantages of applying a thread Graft over a normal wedge (or cleft) graft is that the branch used is continually being fed from where it is growing from the trunk or branch. It doesn’t rely on a quick fusion to survive.

Other methods such as wedge grafting, ‘T’ grafting etc require a reasonable amount of skill to do correctly and to ensure the graft takes. Thread Grafting can be done by just about anyone with a good expectation of success. I’ve done many thread grafts, and so far I’ve only had two failures. One was because my dog snapped it off, and the other was because a caterpillar that thought it needed the growing tip more than I did.

Below is the method I use. To do it, the tools required are:

A Drill – variable speed or a hand drill.
Drill Bits.
Grafting tape.
A drinking straw.

The tree used here is a Liquidambar – but this method is suitable for just about all trees, in particular Broad Leaf and Deciduous trees. I haven’t seen or heard of anyone doing a Juniper, but I know of one person that intends to thread graft a Black Pine. It’ll be interesting to see how that one goes.

Now, how to do it:

Select where you need the branch. In the first photo there is a long section of trunk that has no branches or shoots. I decided I needed one where the arrow is, so I marked it with an angled line. That is the angle that I will drill the hole required.

Next, select the branch you will use as the ‘donor’ and remove all the leaves and any buds except for the bud at the very tip:

Select a drill bit that is slightly larger than the diameter of the branch to be used or the bud – whichever is the largest. With Liquidambars, the bud usually has the largest diameter, but this one is slightly smaller. Figs such as Ficus Benjamina have very narrow (and very fragile) growing tips.

Drill a hole directly through the centre of the trunk/branch at the angle you require. Use the drill on a very slow speed! If you do it at high speed, you will cauterize or burn the soft tissue in the trunk. That can stop or drastically set the fusion process back. Also, you have more control over the drill on a slow speed. This photo shows the exit hole:

Cut a piece off your drinking straw a few centimetres longer than the diameter of the trunk/branch and split it all the way up the one side. Open it up and wrap it round the donor branch:

Slide the straw up and over the bud or growing tip. If the straw is larger than the branch, it can then be rolled up so that it is snug against the branch – like grandpa used to do when he rolled a cigarette. This protects the bud while it is being slid through the trunk. It is imperative you don’t damage the bud in any way otherwise you would most likely have a failure of the graft:

Slide the straw and branch through the hole – hold the straw and the branch while doing it – don’t let the branch slide through the straw. The second photo below shows the tip inside the straw:

When the branch is completely through the hole, hold the branch from the back and gently pull the straw through leaving the branch in place:

Slide the branch through until it is at your desired length. The length doesn’t really matter but if you only have a very short branch showing, it will take longer to develop to the required length than having a longer one. When it is about where you want it, move it back or forward until you find a node or where a branch or leaf was previously cut off. This would be the most active part of the branch in relation to the cambium layer which will do the fusing. It can be done on a bare section of the branch, but may take longer to fuse:

Note which one it is and either slide it a little further out or slide it back until it shows by the entry point:

Lightly scrape the bark on the underside of that node until green tissue is visible – don’t cut into it, just lightly scrape with the edge of a blade. If you scrape too deep or cut into it, you will run the risk of cutting through the phloem and cambium layers. The phloem layer is what feeds the branch from the roots. The cambium layer is what will do the fusing. Now slide the branch back until the section you scraped is just showing through the hole. This will ensure the cambium layers on the trunk and the branch are aligned together. The branch will be a bit smaller than the hole, so use a couple of pieces of tooth-pick or matchstick – or as I prefer to use, a couple of twigs off the same tree with one end shaved into a wedge and slide them in on the top of your branch. Push them in tight to ensure good contact on the bottom of the branch and then cut them off flush with the trunk. The reason for ensuring it is the bottom of the branch and not the top that is in contact with the trunk is because the phloem layer mentioned above is what will feed the branch when they fuse. Water and nutrients flow up the trunk just under the bark. The cambium layer will create a callous and also the new fused phloem layer:

Some people use cut paste to seal around the branch. I prefer not to because if it gets in between the branch and the trunk, it could stop the graft from fusing. I just wrap grafting tape in a figure of eight a few times – front and back:

Finally, wire the branch in place to stop it moving:

That’s it, the Thread Graft is finished! It doesn’t need to be put in shade or anything; in fact it will fuse quicker out in the sun. Just put it somewhere that it won’t get knocked – and watch out for caterpillars! Keep watering and fertilizing your tree as normal and it will fuse. When you see that the branch is visibly thicker where it exits the trunk to where it enters, then the fusion has taken place and you can then sever it where it enters. How long will fusion take? I have no idea. It depends on a lot of factors such as the species and health of the tree, the time of the year the graft was applied (with most trees spring is the optimum time because they are at their peak growing period) and the after care. This photo below is a Thread graft I put on a Ficus Retusa, and the fusion is evident by the exit (green arrow) being considerably thicker than the entry point (blue arrow). This one is now ready to be severed:



A seed is actually a tree packed ready for travel. (Bill Funk)

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10 years 1 month ago #17093 by Rod Lovett
Taffy thanks for this very informative tutorial , mate there is some great info here for anyone wanting to have a go at thread grafting. I use this technique myself and have had a great deal of success with it, you have given me a top hint using the straw . I find with thread grafting that you do have to be careful when threading the graft as you can damage the buds, using the straw will stop this from happening..... thanks Taff great hint!
Cheers Rod...

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10 years 1 month ago #17095 by Leong Kwong
Thanks Taffy you are an ACE.

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10 years 1 month ago #17096 by Shannon young
Good on you Taffy great tips....top job mate!! :)


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10 years 1 month ago #17097 by Kris Matthews
Thank you very much Taffy. When it comes to grafting and the techniques involved I have had very little exposure. This tutorial is fantastic and definitely helps to cover all aspects of this technique. I also like the idea (mentioned earlier) about having a distinct area in the forum for "techniques and tips" so as to easily access information like this.

Thanks again Taffy this sort of information is really appreciated. Cheers Kris.

Only when the last tree has died, the last river has been poisoned and the last fish has been caught will we realize that we cannot eat money.

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10 years 1 month ago #17098 by dean sear
after being away for the last week with hospital i saw this thead and taffy i must say it is very good info and will come in handy for everyone when i am back on feet i will try this method love your work
cheers dean

a simple question or hard should at least be answered or attempted to be solved
cheers dean

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10 years 1 month ago #17101 by Jerry Meislik
Very nice tutorial. Good work.

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