I tried grafting the NG scions you sent me last year to my large rootstock in the field. I stored them just like all my other persimmon scions, but they got mold. When my persimmon grafting time came (about 10 May most years), only one NG scion had green when I did the scratch test. I used it but it must have been too far gone and didn't take.
To solve that problem, I brought some of my containerized persimmons in after they had enough chill hours around Christmas and warmed them up under lights. You were gracious enough to send me more NG scions. I used them all grafting to the containerized rootstock. If I had any left, I would give them a try but I don't so I can't graft NG to my natively growing field stock this spring.
My plan is to grow these containerized grafted NG through the summer in the Rootbuilder II pots and let them go dormant and plant them in the field this fall. I will then wait until next spring. I'll wait until the very last minute before bud swell and prune them to collect scions. Hopefully the shorter the period I have to store the scions, the less chance of mold issues. Then next spring I'll try to bark graft to my native rootstock in the field.
It is funny. I have gotten American persimmon scions from all over the country including from you and none have shown any indication of mold. There must be something about the hybrid that makes it more susceptible.
At any rate, thanks again for the scions and I'm looking forward to tasting the fruit. While my primary focus is for wildlife management, I'm not at all above eating my fill
Glad you enjoyed the thread. I have since modified David's technique a bit and improved my success rate even more. I no longer scrape the bark off the back side of the scion. I found that if I'm slightly too deep I break continuity of the cambium. Instead I make a small shallow back cut. I got this from Dr. Shengrui;s video on bark grafting Jujube: Grafting Jujube. The other thing I do is to make a very slight shave of the bark from one side of the grafting cut to expose the cambium on one side. I align that side against the cambium of the rootstock under the bark flap. This gives me 3 points of potential cambium contact, The front (rootstock side of scion) because there are still cambium cells left on the wood, the one side that I shaved where I have cambium alignment, and the back side of the scion where I make the Dr. Shenguri cut under the flap.
I also learned how important pressure is when bark grafting larger trees in the field. I use electrical tape because it stretches and gives me a lot of pressure. I found that not all parafilm is the same when wrapping the scion. I have fallen in love with Parafilm-M. It comes in 2" sizes but I usually cut it in half to make one inch strips. I've also learned to wrap the scion before grafting, not after. When I wrap after, it causes movement in the graft. I use bamboo with cable ties to keep birds and such from landing on the scions before they are solid. I've also learned that sealing cuts on larger trees can be a problem. It is a large wound to seal, but a liquid like Doc Farwell's or latex paint can run down into the graft. I usually wrap a small piece of parafilm at the base of the scion before sealing it to keep this from happening. I've also recently started trying wood glue for sealing scions. That seems to work well but you still have the runniness problem. One final thing I do is to use a little rooting hormone on the scion where the cut portion sticks above the rootstock. I've seen conflicting studies on this, but I think it promotes callusing which the graft needs to knit.
With a couple years under my belt, it is now pretty rare for a persimmon bark graft to fail on native rootstock between 1" and about 5". My success rate has not been that high with bark grafting to small diameter container grown rootstock. I did get about a dozen to take this year.