There are dozens of things that could have done in your grafts. My first guess would be you did not align the cambium layers precisely. Cleft grafts are not usually done on equal scion size, for that you should do a wedge type graft, you will get much better contact that way. The whole key is getting those cambiums aligned. If you don't know where the cambium is look it up. Another way to get persimmons in particular to fail is it was not apically dominant. You need nothing there to compete with the graft, the tree will not feed a lower graft if there are higher places it can push leaves. You need to continually remove any competition or the persimmons will not take. For my persimmon grafts this spring I had to rub off shoots every other day to get the grafts to work in the end.

Re: storage, if the scions look fresh they are usually good. Nearly all the time I had failures the scions looked bad before I started.

Scott

you stored them correctly. It was a good date for grafting. I suggest you practice whip and tounge grafting on random branches now, so next spring you are better at it. Also practice you cleft. I like to see an inch or more of length of a cleft graft. not much less in W&T.

One other tid-bit. On this forum in the past I recall reading that there are issues with grafting asian pears and euro pears onto each other. Not that they won't take in the first place but that they won't succeed in the longer term to produce fruit. same with apple and pear, you can get the graft to take, but it will fail before producing.