graft post-mortem questions

12 years ago

I started whip and tongue grafting pear trees (mostly onto well established wild callery seedlings in the field) this year on March 7, and I've had enough time now to see some failures and to see some different patterns in the failed grafts. I'm hoping some of you on this list can help me understand what happened and maybe how to avoid repeat problems in the future.

Almost all of my grafts began to grow this year with the main exception of one batch of scionwood. The cambium layer definitely looked green still when I grafted, but none of the 3 grafts I attempted ever grew at all. It seems like the problem probably had something to do with the scionwood before I ever grafted it.

The other problem I had was buds that began to elongate and in some cases even open up into unfurled leaves (just like the grafts that still look good) before pretty rapidly wilting and dying. I've never had grafts fail in that way before. When I unwrapped the rubber bands to look at the graft union the area under the rubber band has mostly been black (compared to mostly normal brownish-gray bark on the rootstock and more young-greenish color on the exposed part of the scion.) I've wondered if I could be wrapping my grafts too tightly or if I should have removed the rubber bands when the buds opened up? Mostly the failed scions appear to have knit together with the stocks neatly, but I haven't pulled them apart yet to see better.

Comments (3)

Konrad___far_north
12 years ago
It could very well be that your scion were not good.
I don't think your rubber band were too tight, I use electrical tape. No, you shouldn't loose the rubber band until well into the season. I take off the tape next spring. It would be good to have some scion put on from a different source,..just to compare.
steve_in_los_osos
12 years ago
I'm not sure about potential scion/rootstock incompatibility issues, but I have experienced the pushing scions which then simply collapse. In those cases I believe there was not sufficient cambial contact for a good union. The apparent "flush" of the scion is just from energy stored in the wood, just as scions kept for a long time in the refrigerator will slowly start to push out their buds. Makes it hard to know when you should just abandon an effort and regraft :-(

I've got two plum grafts out of eight plum/peach grafts that are making me nervous because of their lackluster leafing out. Makes me wonder about them, and the backup wood in the fridge is not getting any fresher.
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marknmt
12 years ago
I would suspect the scion wood too.

I think that it might be possible to wrap the graft union too tight with rubbers. I got carried away for a while wrapping mine and had a few failures that might be attributable to that, and the bark was quite dark when I finally removed them. And I could clearly see the imprint of my wrapping. The bark appeared compressed and shiny. But I never had the problem with pears- just apples.

Good luck,

Mark