If all are successfull how many will you keep?
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When using an offset cleft graft on a side branch that is somewhat larger than the scion, I assume that it is better to make the branch cut horizontal and offset toward the bottom to maximize cambium fluid flow into the scion. However, I couldn’t find any guidance about this on the Web. Is my assumption correct? The cut in the branch is offset to match the cambium layers on both sides of the scion, which seems like a good idea; but I haven’t tried it yet.
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Good point. I was thinking more from a structural point of view. As the graft is healing and the branch receives loading downwards (fruit, wind, birds), which position of the graft on the host is stronger?
Bottom? Top? One of the sides? Which shear modulus give you a stronger connection, everything else being equal.
Maybe there is a structural engineer in here. My structural engineering courses were all for non-major and in my sophomore year (1984!)
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I believe this in reference to a callery I put 8 varieties on? Four of them are still there, one the wind blew off after it grew about 3 feet. I’ll keep all the varieties, and probably add more next year to get the number back up to at least 7 or 8.
I’m sure it’d be no problem getting a dozen and more different pears onto a callery root once the tree has enough size and branches.
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A whip & tongue graft offers the most support in breezes and birds lighting on the grafts.
And if a cleft or bark graft…having the best connection in the direction of prevailing winds gives the best chance it doesn’t break at the graft from wind.
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So did a bit of boning up on shear and bending stresses.
Grafts on top and bottom (assuming host branch is not vertical) are stronger connections than side grafts.
This is for cleft or modified cleft grafts.
By top and bottom I am referring to the vertical plane facing the sky or the ground. When a downward force is applied those two positions will be in bending while grafts on each side would be in shear. Contact points for the graft (just like welds) are stronger in bending than in shear.
OK nerd mode off.
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Your conclusions don’t make sense to me.
Are you suggesting that cambial union is more mechanically resistant to tension (pulling apart) than to shear (sliding faces) and that is why you are focusing on shear?
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There may well be significant differences when comparing the graft scaring during early healing from grafting to a metal weld.
It’s just the way I look at things, a symptom of my schooling and career.
Welds typically are stronger in tension than in shear. Strength is designed around shear which is conservative
I’m wondering if grafts behave the same way… Specifically the placement of cleft or modifies cleft grafts.
I was hoping there has been some work done by some to say whether it’s been observed or is anecdotal or that it had not been observed to be different.
I’m also curious how folks here label and keep track of their grafts. Obviously a written (computer) record is nice, but how do you label on the trees? Tape and permanent marker? Metal tags? Plastic tags?
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I generally just try to position my cleft grafts so that they seem most stable in that moment, i.e., when the two sides of split rootstock are above and below the wedge of scion. Or to put it another way, split the rootstock horizontally, not vertically. Here’s one from a couple years ago on a greenhouse multi-graft avocado:
It’s possible this is not the most structurally sound way to do it, but it seems like it would be.
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I have an embossed tag which I paid dearly for. But I have every intention of using them over and over by just writing in a small corner, then when the graft fails, I just cross the name and reuse the tag.
And I don’t think too hard about my grafts either. I read the grafts pointing up have better chance of surviving so that’s what I did. All of my espalier trees, I grafted them up vertically, not horizontally.
You can tell, I’m in the don’t worry, be happy camp.
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The right way to do it in my opinion. That puts the healing scar in bending or tension and compression when you put weight on the branch downward.
I don’t think it’s wrong to try to apply engineering statics and dynamics to healing grafts.
It may not be a huge difference but I think there is one.
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If all other considerations are equal, engineering dynamics are probably important; but I think that in most cases the quality and amount of scar tissue around the graft will be the most critical factor controlling its strength.
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harrow delight on seckel on right, graded in May + little yellow pear on left which is a late season graft not taken yet. this was a cut branch from the harrow that never leafed out, apparently the branches were alive but not the roots.
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I found a few scions in my fridge a neighbor gave me this spring. They seem to be okay and the cambium is still green. Is it too late to try grafting them on my existing apple trees?
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give them a try. what do you have to lose?
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If I understood you correctly - a side branch somewhat horizontal - no, it’s actually the opposite. Due to the nature of growth regulation in plants (auxins), growth on the upper part of a branch is favored. Although I don’t think it will make a significant difference in this example.
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