My experience is with apples, not cherries, but I have seen successful grafts respond differently, with the one extreme of very quick and vigorous growth with bushy leaves, to the other extreme where the only way I knew the graft had taken (other than by looking at the graft union itself) was that the buds swelled up almost like balloons but never leafed out for a whole season. Regarding the latter example, the growth was very vigorous in the second year, even though the graft had apparently healed very nicely in about 2 months time. Sometimes it seems, healing takes just a little extra time.

With cherries, the rumors I hear are that the grafts will be less successful than on apples and pears. With pomme fruits, an experienced grafter can get 90% or more of the grafts to take. With cherries and stone fruits grafted in winter/spring, on the other hand, it seems the success rate might be closer to 50/50, even for experienced folks. You might have better odds with bud grafting in mid-summer. But I could be wrong, this is just the impression I have gotten from others. So anyway...

What I would look for on any graft is the swelling and growth of buds on the scion. And give the grafts a good 2-3 months before "deciding" whether they have taken or not. Patience is key. You don't want to accidentally break a graft that has begun to take, and it takes several months before they are healed well enough to handle any appreciable disturbance. Patience!

I figure in about 3 months, you should be able to figure out which grafts have taken, and which are just taped on but totally dead. On dead grafts, the buds will look the same as they did the day you grafted them, and the bark might begin to shrivel. If you scratch the bark lightly, it might not be green underneath anymore but just gray. Those grafts are certainly dead. However, if there is any hope to life at all and it is NOT obvious whether the grafts are dead, I would encourage you to just leave the grafts alone. Who knows... maybe next season you'll experience a flurry of new growth where the graft previously spent all its resources healing and forming callus tissue instead of growth. With the callus fully healed, whether it takes 1-2 months or 12 months, the graft will be ready to send out a slew of new shoots.

Cheers!

Oh yeah, I plan on leaving them there until next season at the very least. I have what I call my zombie cherry tree that taught me that lesson.

First year I had it, it leafed out okay and then seemed to wither away and die by mid-summer. The other cherry tree was fine, but this one looked *DEAD*. I didn't get around to pulling it, then it was winter and it was cold so I kept putting it off... then it was spring again and suddenly the "dead" tree bushed out like it was making up for lost time and is now the bigger of the two cherries.

So yeah, I'll leave them on there until at least next season, mostly because it'll be too late to really do more by the time I find out for sure one way or the other, and like you said, never know when my zombie cherry tree might have zombie grafts as well.

I had 2 tiny persimmon seedlings and a moringa oleifera seedling both come back from the dead this spring. I was absolutely stunned in each case.

I'm out of town on a 3-week trip, and very eager/nervous to get home and see how my grafts (and the rest of my garden) has done.

Obviously, the key to grafting is getting the cambium layers aligned. As stated above (correctly) different grafts react differently. The rootstock is key. When that rootstock want to push growth...if all systems are "go"...things will happen within 2-3 weeks. Watch the leaf buds swell! You are betting on growth push/connection before the scion drys out.