Doing a search “Peach graft” brings up several (I stopped counting at 8) topic on the subject. If others have poor success as I do I can understand why.
The first two years of failure I attributed to my novice status but now, at year three, I believe it’s other factors. Apples, pears, plums, cherries, and apricots I have decent success using several techniques. My peach grafts fail.
5/2 I did 4 bark grafts. They showed some green and then died a week later. 6/4 I cut them off and tried again. I see a small amount of green on 2 of the 4 but now on 6/19 nothing is happening. Clef grafts have also failed. I’ll know in the next two weeks if there is some success. When I have to time I need to read all the threads and try to figure this out.
Look at the high temps for the week or so after you did the grafts. That is often the reason for failure of peaches. Also a really hot weather spell several weeks in can be bad.
OK, I didn’t get to it last weekend, but I’ve checked my grafts and now have the following to report.
It’s conceivable that some of the late ones will still leaf out, though it is probably more likely that some of the late ones that did leaf out will die. This data shouldn’t say that late grafting can’t work- just that with my skills and approach it doesn’t work all that well. I know I’ll be doing a greater proportion of them earlier next year.
Caveat: Dates rounded by up to 2 days, so that I could better group results. For example, I didn’t want to have 3,4, and 3 when I could report 10 for the middle date.
I excluded grafts to new rootstocks. If I had not, there would be an extra 2 takes in 5 graft on 5/6.
With you skill at your site. My grafts made around May 20th seem to mostly be fine- some growing more than others, but none have stopped growing and died- I’ve never had a peach graft do that. A lot of apple grafts in my nursery look terrible, but the trees roots were disturbed quite a bit in spring. Apple grafts on older trees not disturbed all took just fine. I made at least 50 peach grafts, by the way.
E. plum grafts were being hit by aphids and leaf hoppers and were looking poor (as well as apple grafts) and psyla has already slowed my pear grafts but I put some Assail on them and all look much improved.
Bob, your statistic is definitely has a trend. It is not just a random distribution. 
Good point- all my peach/nectarine grafts were at a single site. I only had a handful of other grafts at different locations.
I agree, though it isn’t a huge sample size. One other factor is that for the later grafts, the scionwood has been sitting around for another month. And whenever I graft, I use whatever looks best at the moment, so, it is likely a double-whammy against the late grafts.
Here’s a look at this year’s plum (including Pluot and Euro plums). There isn’t anywhere near as much of a trend, though I think there is a bit of a dip at the end. I should measure last years grafts to see how significant a size impact the time of grafting has, 1+ years later.
I’m pretty surprised by that. I think Scott mentioned it happening to him and it is a regular occurrence for me, so I generalized that it was common. And I don’t mean that it put on 4" growth and died- just that it made small leaves, which then wilted and died. It doesn’t happen to a majority (obviously), but maybe 10-20%. More often for the later ones I think.
I’ve seen the same thing happen with plums sometimes, though not as often. In fact, I suspect that some from the tail end of the plums may not make it, pushing down the later success rates a bit.
The 4 bark grafts done 5/2 on a 3 inch Citation trunk showed some green and then died. Weather was cool with temperatures in 60s and 70s except for two days in a row at 89.
After that failure 2 inches was cut from the trunk on 6/4 and I tried again with 4 more bark grafts. Two showed some green but after two days of mid 90s they looked dead. A cleft graft, peach on peach, also failed. All Scion was well wrapped. I’m batting 0. Apple, plum, apricot and mulberry during the same time frame are doing OK.
Now it’s time to try T budding with the remaining scion. The Scion my be too old but I’ll give it a try.
Those temps don’t sound horrible, but you should have protected them with aluminum foil for those days near 90. Did you have the scions completely sealed? That ups the odds - either use a paint like doc farwells, or parafilm.
June is often too late for peaches, the tree has moved out of the spring growth spurt phase as far as hormones go. So, you have to make it work in May. At this point you may want to wait and try chip buds in July.
I still have some peach scion wood in the refrigerator. Is it worth using for budding or other type of grafting or should I just discard it?
It may partially depend on crop load, because peaches are active growers throughout summer. So far, my late May grafts are doing fine, but then, my season is a couple weeks later than yours- at least a week, anyway. I picked my first Flavor May peach yesterday- clean as store bought. Most flowers seemed to have been killed, however, by Feb. plummet. It is the only peach or nectarine in my collection where this happened.
It has to get very dry to completely stop peach growth. But it can easily get dry enough to make T budding difficult or impossible. The bark isn’t slipping well enough.
This is an interesting trend, Bob. Here are my results for peach/nectarine grafting in 2017 (this was my first year grafting peaches & nects). Weather-wise, I’m about one month ahead of you.
When looking at your data, I would toss out the 0/6 on newly planted/potted trees. They are much harder to be successful with than established trees.
Once you do that, and roll it up by date:
March: 9/20 = 45%
April: 6/6 = 100%
May: 1/5 = 20%
So, it looks to me that maybe there is a best time to do it, but if you do it a bit early, you can still be reasonably successful. It’s hard to say with such a limited sample size (same issue with my slightly larger data-set).
I have not had time to tally my grafts. Will do it soon. I think I have done well but not as good as last year. I blamed it on the fluctuating weather, not the grafter 
The good news is I am 100% on pawpaw (1/0) and persimmon (3/0) this year.
Especially when my relatively large sample size of grafts done May 20th is an aberration to the assumption that early enough to beat summer heat is necessarily better. I haven’t bothered counting my grafts to do this in a scientific manner but I haven’t found more than 3 non-vital grafts. However, some haven’t pushed enough growth yet for me to be confident of their survival, although none of the non-vital grafts ever pushed any growth. Sometimes grafts start to grow and are subsequently hit by OFM, in the case of peaches, and leaf-hoppers and aphids in the case of most other species I graft ( also psyla for pears). These insects need to be controlled when they are prevalent and in my area they always are.
Peaches were difficult for me this year, I blame the weather! May was either cold and wet or scorchy hot, June similar.
Last year I had 90% take, this year was the flip side at 10%.
I will bud graft these in the future…
Peaches and nectarines grafted last year are doing great and will be ready for new homes by next season.
I had some peregrine and indian free this year, did like 6 gtafts of each to american plum. I had about an 80% take initially.
Left for work 2 weeks in az where the weather here went into the 90s and even though wife watered well i am down to 1 single peregrine chip-budded. Everyone else scirched and withered.
Strangely almost all my j plum grafts crapped out too, but nearly all apple, american plum, euro, and persimmon took.
Which graft technique did you do for your peaches that worked? I’m grafting into Lovell root stock and want to maximize my chances of success 
Definitely search for peach grafting in the forum search. There are piles of other threads.
To summarize what I’ve read: peaches and nectarines are hard. Late summer budding (T or chip) seems to work better. They callus at higher temps than other fruit.
Ton of answers to your questions.
Here is one of the threads. Scott and Olpea (aka Mark) gave some good advice here.