I did some apple cleft grafts last August, in addition to the chip grafts. I figured that if I have success with clefts in the spring (and never have much success with budding), that I should try them in the late summer too…
Results are in:
Chip buds: 1 in 12 made it (a couple more appear to have callused over nicely, but the bud looks dead)
Cleft grafts: 4 in 6 took, but only 3 are alive now (I broke one with my head…)
Now, this isn’t to say that clefts are better than chip buds during the summer. That would contradict everything I’ve seen online. But, if you are completely incompetent at budding, cleft grafts are a reasonable possibility. I should also mention that none are growing particularly vigorously. I think some of my spring grafts may have passed them, so it may be most useful for when you have the summer wood and don’t think you’ll have access to it the next spring for whatever reason (cut or dying tree, moving, etc).
Here are a couple pics. Note the parafilm which is still visible on the 2nd. I removed most of it this spring when I was taking stock of how things did and removing the green tape that held them together. You can see a few somewhat failed chips in the pics as well. I experimented with longer chips this time (in hopes of more cambium contact), but had the same dismal results as when I used smaller ones.
Clefts from 8/16/2015:
Freyburg:
Lobo: