Can I graft onto a calloused wound (or is that area effectively 'dead')?

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The title pretty much sums up the question. I have been making pretty but cuts on trees I am field growing, and the wounds are callousing over nicely. The calloused area in some instances will cover perhaps half of the circumference of the trunk. Is that calloused area inert? I mean, is the a cambium layer and can I graft onto a calloused wound?

Thanks!
 

0soyoung

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There will never be a bud originating from the natural 'scar' cover.

So, the only way to get one (or more) there is by grafting. @Ohmy222 could have a bud in the middle of that pruning wound had he placed a node between the two grafting pins. But, alas, he either didn't think about it OR he doesn't want a branch to ever be there.
 

jason biggs

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i think a lot depends on the species and ones climate...
ficus for example are much easier than most, they also throw aerial roots to cover dead areas...
 
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Onc eyou get it to grow tissue over it, there is a living layer over the cut, which in time can be used for grafting.
yeah, it can be grafted on. Some actually approach graft to close big wounds by taking a seedling and fusing it across the wound. This is the a rough example from a Google search. I haven't seen it gouged out like this before though.
There will never be a bud originating from the natural 'scar' cover.

So, the only way to get one (or more) there is by grafting. @Ohmy222 could have a bud in the middle of that pruning wound had he placed a node between the two grafting pins. But, alas, he either didn't think about it OR he doesn't want a branch to ever be there.

Many thanks - this is exactly what I wanted to know. Much appreciated!
 

Ohmy222

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There will never be a bud originating from the natural 'scar' cover.

So, the only way to get one (or more) there is by grafting. @Ohmy222 could have a bud in the middle of that pruning wound had he placed a node between the two grafting pins. But, alas, he either didn't think about it OR he doesn't want a branch to ever be there.
or i ripped a random image off google :)
 

0soyoung

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or i ripped a random image off google :)
I'll also say that this method will work better if the stem being grafted
  1. more nearly parallels the axis of the stem to which it is being grafted (instead of across it as in the pic) AND
  2. the tip of the stem is up toward the tip(s) of the stem to which it is being grafted.

I learned this with (scholar.)Google's help. Fair enough for both of us. 😉


PAT
 

jason biggs

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2 x ficus microcarpa with large deadwood sections...
in the first picture i thread grafted a rooted cutting a year ago and now 2 small rooted cuttings that are
starting to take... i don't think the ugly deadwood ever goes away but lets see.... (think i am going to keep
on cleaning areas of the scar down to live tissue??
the 2nd tree i have thread grafted 2 x branches.20210911_133443.jpg20210911_133534.jpg
 

hemmy

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I am sorry but this will not work the way you think it does. It needs to merge with living tissue on the exit sire of the wound.
This is an interesting area of exploration. On a thread graft, is it a requirement to remove (or NOT remove) the cambium and phloem of the “scion”? If it is intact, how does the inner cambium, phloem, and xylem fuse for transport? If it is removed, then is it the inner cambium and phloem callousing at the exit site that create the connection to the phloem and xylem? Is thread grafting even done in commercial horticulture?

In a non-thread graft, the cut site supplies access to cambium, phloem, and xylem of graft scion. I assumed they all made connections to the corresponding tissue on the host plant. But apparently the callus formation at the union site can be responsible for eventual tissue differentiation into phloem and xylem which creates the vascular connections. But the callusing isn’t an absolute requirement in some plant species.

It isn’t clear to me how the phloem and xylem connection and transport occurs. Here is a great paper exploring the process.

Melnyk, CW. Plant grafting: insights into tissue regeneration. Regeneration. 2017; 4: 3– 14. https://doi.org/10.1002/reg2.71

“Callus and tissues surrounding the cut differentiate to phloem and xylem before the vascular strands are connected between scion and stock”

“Together, these data suggest that callus formation at the graft is not an absolute requirement for successful graft formation or vascular connection. Callus formation is important to promote grafting for many plants (Garner & Bradley, 2013), indicating that the importance of callus may be species specific. Whether callus is a cause or consequence of successful grafting remains unknown.”
 

hemmy

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2 x ficus microcarpa with large deadwood sections...
in the first picture i thread grafted a rooted cutting a year ago and now 2 small rooted cuttings that are
starting to take... i don't think the ugly deadwood ever goes away but lets see.... (think i am going to keep
on cleaning areas of the scar down to live tissue??
the
On the first one, if the trunk can be slanted so the wound is on a side and the branch entrance of the thread graft is on the soil side; then couldn’t you promote root formation on the bottom portion and create a “new” plant that will thicken and grow through and over the wound? Although if it is constructed by sapwood in the interior maybe it would split the tree or constrict itself? Perhaps the better solution is fusing an add on plant with roots that climb down the outside from the deadwood to the soil? Which it sounds like you are doing by rooting the cuttings in the rotting wood.
 

Leo in N E Illinois

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One of the easier methods of grafting with deciduous trees is bud grafting. The scars are usually pretty minor, whether the bud takes or not. It is really worth looking into bud grafting. It can be done late summer into autumn.

As to grafting into scar tissue rolling over a large cut wound. It the cut was to remove a branch, surrounding every branch is usually a collar of dormant buds that normally are not visible. The collar becomes visible if you cut leaving a stub. Over the next year the collar will swell, and become visible. Then go back and cut the stub flush to the collar. The buds in the collar will activate and you will have a ring of buds sprouting around the wound. Keep one or two of these buds to be replacement branches.

If when you remove a branch you gouge into the wood of the trunk, often you remove the collar of buds ringing the removed branch. Then you must graft to get a new branch at that point.

If the wound is a trunk chop, there is no collar of dormant buds. Here various grafting techniques are needed if the tree doesn't back bud where you need it to back bud.

You can graft anywhere that you can expose the cambium. The cambium of the understock and the cambium of the graft MUST line up. Sometimes in scar tissue rolling over a large cut the cambium is not a "flat sheet" and it can be a little difficult figuring what angle the cut needs to be, but you can graft anywhere you can expose the cambium and mate the cambium of the understock and the scion.
 
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