Query regarding thread vs approach grafting on JMaple

[Lars Grimm]

Hi All,

I commonly see folks talk about developing a good trunk and then grafting on all the branches in good locations, but not which grafting approach to use in these circumstances. I am making plans for this coming spring and am debating the pros/cons of thread grafting versus approach grafting new primary branches in appropriate position.

I have a Japanese Maple with a trunk up to 3" thick and very few good primary branches. Approach grafts would be easy, but I doubt I could get the angle to be as close to horizontal as I want in some locations. Thread grafts could easily get the correct angle, but I would be threading them through several inches of primary trunk in several places.

Is there a limit to how long a thread graft can traverse the trunk before exiting?
Any reason to favor thread vs approach grafting for primary branches on larger sized Japanese Maples?

Thank you all as always for the feedback.
Lars

 

[TomB]

Thread grafts are easier and give a more aesthetically pleasing result in my view. I've not done one through a trunk more than 1-2 inches thick, but I see no reason why it wouldn't work with a thicker trunk - what matters is the join at the exit point.

 

[0soyoung]

• The nearer to perpendicular that you want the line of the branch to the trunk, favors thread grafting. There is no limit to how thick a trunk can be other than the practical limit of being able to drill the thread 'eye'.
• The nearer to parallel that you want the line of the branch to the trunk, favors approach grafting. Approach grafted branches tend to emerge tangentially from the trunk (which is quite weird and unnatural in some circumstances - the same is true for free scion grafts).
• The nearer the graft scion thickness is to the trunk thickness (at the grafting point) are to equal, favors approach grafting
• Approach grafting is appropriate for root grafts.

 

[sorce]

I don't think you'll have a problem drilling through 3 inches. My ficus is close to that.

Couple things DO change though.

More time drilling will build more heat.

The distance of drill makes it more susceptible to hit a rotten section.

The longer the distance the more branch taper will cause your exit side to be quite gappy.

I'd try not to leave a node within the trunk.
Getting growth with a long enough internode would help, and also negate the taper problem. Since usually there is no taper within an internode alone.

Consider cuttings in pots, seperate scions, to give you more freedom of entry and exit points.

Cheers

Sorce

 

[Dav4]

I have had success thread grafting palmatum trunks upwards of 3" wide, and plan on attempting more this spring on even larger material. I may approach graft as well, but plan on doing this only at the root base or up in the canopy where I've got some callused chop scars.

 

[BackyardBonsai]

I would like to see some example of a 'good' approach grafts. I have a hard time see how that will look good as explain by @0soyoung - Approach grafted branches tend to emerge tangentially from the trunk. The picture in my brain has the branch on the side of the trunk which would look weird. Anyone with good approach graft can help me here by posting a pic or two.
Thanks.

 

[Brian Van Fleet]

Adding branches to a trunk is easy with thread-grafting. It’s not messy (essentially no scars), you can pick the exact angle, and place the first bud on the exit side anywhere you want...ideally on the side, and really close to the trunk.

When drilling, remember to drill through the exit side, and that the only place the graft actually attaches is at the cambium at the exit side. Drill the hold big enough that you’ll have some viable buds on the exit side, wedge the entrance side with a little shoot from the same tree, and seal cuts well.

 

[Mike Westervelt]

Brian,
That's interesting about your wedging technique, I was taught to wedge the exit side and to put the wedge(bamboo) on the bottom of the shoot so it contacts the cambium at the top of the hole?

 

[Brian Van Fleet]

Brian,
That's interesting about your wedging technique, I was taught to wedge the exit side and to put the wedge(bamboo) on the bottom of the shoot so it contacts the cambium at the top of the hole?

Yeah, I meant wedging a shoot into the exit side, to ensure good cambium contact. Here is a shot of a thread-graft on my Chishio JM. Took 2 years to take. Exit side, just loosely wired for the first time last month. Notice how close the first bid is to the trunk, and how it emerges toward the front on the side:

Entrance side (back of trunk), just separated in the fall:

 

[Lars Grimm]

Adding branches to a trunk is easy with thread-grafting. It’s not messy (essentially no scars), you can pick the exact angle, and place the first bud on the exit side anywhere you want...ideally on the side, and really close to the trunk.

When drilling, remember to drill through the exit side, and that the only place the graft actually attaches is at the cambium at the exit side. Drill the hold big enough that you’ll have some viable buds on the exit side, wedge the entrance side with a little shoot from the same tree, and seal cuts well.

My understanding of why to do the exit side is to ensure you get the hole in the correct spot and to prevent splintering/blow out that can occur when the drill bit comes out the other side. Is that correct?

 

[0soyoung]

I would like to see some example of a 'good' approach grafts. I have a hard time see how that will look good as explain by @0soyoung - Approach grafted branches tend to emerge tangentially from the trunk. The picture in my brain has the branch on the side of the trunk which would look weird. Anyone with good approach graft can help me here by posting a pic or two.
Thanks.

The scion axis will be nearly parallel the axis of the trunk and so makes a close 'V'.

the only place the graft actually attaches is at the cambium at the exit side.

And this is why thread grafting is not suitable for root grafts.

 

[Brian Van Fleet]

My understanding of why to do the exit side is to ensure you get the hole in the correct spot and to prevent splintering/blow out that can occur when the drill bit comes out the other side. Is that correct?

Yep

 

[River's Edge]

Here is an additional picture, trunk is over 3 inches in diameter. The whips are propositioned for grafting in spring. This lowers the chance of breakage when performing the graft.
One tip that i have found useful is to use a Brace & Bit type drill. Allows one to drill slowly and carefully for alignment. The older drill bits have plenty of length and drill live wood easily. This limits the heat build up and subsequent cell damage.

 

[Lars Grimm]

Here is an additional picture, trunk is over 3 inches in diameter. The whips are propositioned for grafting in spring. This lowers the chance of breakage when performing the graft.
One tip that i have found useful is to use a Brace & Bit type drill. Allows one to drill slowly and carefully for alignment. The older drill bits have plenty of length and drill live wood easily. This limits the heat build up and subsequent cell damage.View attachment 275424

Are the Brace and Bit type drills the old school manual drills? I've never heard of that brand/type and this is what Amazon gives me.

 

[River's Edge]

Are the Brace and Bit type drills the old school manual drills? I've never heard of that brand/type and this is what Amazon gives me.

Yes they are, the old school carpenter style. Bits are approximately 11 inches in length. I have also used " IRWIN" brand bits in the old manual system. It also helps to drill a smaller hole from the exit point to entry point first to ensure proper angle and placement. The Brace & Bit as well as old bits are easily found in second hand stores or garage sales.