Honestly, I got really lucky with the form the tree was in when it was delivered. I did train and prune it from the beginning with the idea that I was going to convert the 3 scaffolds into different varieties. The 4th runt of a branch being changed into a nurse branch of the original Shiro was a last minute addition.
We’ll see how lucky I get with the grafts surviving seeing as I grafted them way earlier than recommended.
My early plum grafts last year started but then half petered out. I never had that happen on plums before. This year I did them in 60’s weather a couple weeks after you did yours.
I know that some grafts fail after a year, but on average, how long do you give a graft before calling it a success?
It depends on how vigorously they are growing. If it is taking off like a rocket it is going to make it. The slow starters are the ones that can be dicey. Stalling is a bad sign. To figure out fast vs slow you need to do a lot of grafts over the years and watch the timing. Most failures never get going, a few start plumping up buds and then stall/fade, and a very few get a bit of leaf growth going then stall/fade. The further they get the less chance they will fail.