"Reverse" thread grafting a juniper?

[circledisk]

I may have an opportunity to work on a fairly large, overgrown juniper with little to no lower trunk growth. The branches are quite thick, and I've been looking at different grafting methods. Would it be possible to do a sort of thread graft on a juniper? In this case, it would not be a traditional thread graft where the entire branch is fed through a hole in the trunk.

The idea I have is to take a cutting, like a scion, and insert that into a hole in the trunk. Has this ever been done on a juniper? Would it take? I can't think of why this wouldn't work. I can work on an illustration if that would be helpful.

 

[leatherback]

Look at scion grafting and/or approach grafting. This is what you are after.

I'll start you off:

 

[Srt8madness]

I may have an opportunity to work on a fairly large, overgrown juniper with little to no lower trunk growth. The branches are quite thick, and I've been looking at different grafting methods. Would it be possible to do a sort of thread graft on a juniper? In this case, it would not be a traditional thread graft where the entire branch is fed through a hole in the trunk.

The idea I have is to take a cutting, like a scion, and insert that into a hole in the trunk. Has this ever been done on a juniper? Would it take? I can't think of why this wouldn't work. I can work on an illustration if that would be helpful.

I can think of why it wouldn't work - the cambium wouldn't be lined up. Leatherbacks answer is the solution for juniper grafting.

 

[leatherback]

peg-grafting has been done for Japanese maples, butafaik only with roots grafted on the to-be grafted peg, to only be cut off later.

 

[circledisk]

Look at scion grafting and/or approach grafting. This is what you are after.

I'll start you off:

I know about scion grafting and approach grafting, I was just wondering if peg grafting was also a viable option. Is scion grafting limited to a specific branch size? I couldn't find any information on scion grafting thicker (>1" dia) branches.

 

[circledisk]

I can think of why it wouldn't work - the cambium wouldn't be lined up. Leatherbacks answer is the solution for juniper grafting.

Does the cambium need to be lined up in that way on conifers? Thread grafting doesn't line up the entire cambium on a deciduous tree, but it still works.

 

[Paradox]

Does the cambium need to be lined up in that way on conifers? Thread grafting doesn't line up the entire cambium on a deciduous tree, but it still works.

If the cambium isn't lined up, the graft will die. The cambium is the living tissue of the tree/branch. If they don't line up, there is nothing to fuse and support the graft

 

[circledisk]

I know what the cambium is...I'm just referring to the technique of a thread graft. You have a horizontally oriented cambium layer pressed up against vertical rings of heartwood, sapwood, cambium, and bark, and those still hold.

 

[Paradox]

I know what the cambium is...I'm just referring to the technique of a thread graft. You have a horizontally oriented cambium layer pressed up against vertical rings of heartwood, sapwood, cambium, and bark, and those still hold.

Yes because there is cambium to cambium contact to fuse together on the exit side of the graft. It doesnt need to be oriented in the same direction

 

[circledisk]

Exactly, so why would a similar graft type not work on a juniper? What I'm saying is that a scion graft potentially exposes more cambium oriented in the same direction between the trunk and the new branch, whereas the thread graft exposes only a small portion of the donor branch to the trunks cambium. Anecdotally my experience with junipers is that they have a thicker cambium layer as well.

 

[Paradox]

Exactly, so why would a similar graft type not work on a juniper? What I'm saying is that a scion graft potentially exposes more cambium oriented in the same direction between the trunk and the new branch, whereas the thread graft exposes only a small portion of the donor branch to the trunks cambium. Anecdotally my experience with junipers is that they have a thicker cambium layer as well.

I think Mark Comstock has done grafts on juniper as you describe: drill a hole in the trunk then insert a scion into the hole making sure there is cambium to cambium contact rather than do an elongated cut to insert a scion wedge

 

[circledisk]

Thats exactly what I'm looking for, thank you. I imagine that this method could potentially yield better results with more mature wood, given the thicker cambium layers and more support a peg offers vs. a scion. I'll try and find his literature.

 

[circledisk]

When I do this kind of graft, is the non-perforated buddy tape enough to preserve moisture, or would the graft take more successfully using perforated tape and a sealed bag of sphagnum around it?

 

[circledisk]

It seems like this technique may also work in the intended way. It looks like a method of scion grafting that exposes more of the surface area of the limb and trunk to each other, almost like a whip and tongue graft. I may have to try this method as well.

 

[Paradox]

When I do this kind of graft, is the non-perforated buddy tape enough to preserve moisture, or would the graft take more successfully using perforated tape and a sealed bag of sphagnum around it?

Not sure. Try both?

 

[circledisk]

Not sure. Try both?

Might as well

 

[Paradox]

It seems like this technique may also work in the intended way. It looks like a method of scion grafting that exposes more of the surface area of the limb and trunk to each other, almost like a whip and tongue graft. I may have to try this method as well.

View attachment 547645

Yes this is the method I described as using a scion wedge. It is probably considered one of the standard ways to do scion grafting

 

[Paradox]

It seems like this technique may also work in the intended way. It looks like a method of scion grafting that exposes more of the surface area of the limb and trunk to each other, almost like a whip and tongue graft. I may have to try this method as well.

View attachment 547645

The other wedge method is just a single wedge as shown in the second video posted by leatherback instead of a tongue graft.

 

[circledisk]

Interesting. I’ve mostly seen single scion grafts mentioned but that may be a product of laziness or the size of the grafts people are mostly doing. I intend on using thicker branches, so a double cut may be more appropriate.

 

[circledisk]

Bonsai Tonight has a few blog posts about scion grafts and he uses the bag and spagnum aftercare method, but that seems too contrived against buddy tape.