You might succeed if your scion wood is not dried out from not being sealed air tight. As soon as your scions warmup they will start leafing out,using up their stored energy. Shade your new grafts to keep as cool as possible. Plan ahead and have what ever you will need. Al

For later grafts I have much better luck with chip or T-buds. I don't know why that is the case but I think it may have something to do with the plants greater difficulty in pushing from a new bud later in its yearly developmental cycle. So, what you do is bud on a shoot and then two weeks later cut 90% through the shoot above the bud and bend it over to the ground, making your new bud dominant but the shoot still getting fed. Note that I don't' do all of my later grafts this way, I just grafted a pear last week with bark and wedge grafts, but I have had too many failures. The pear was on a big trunk so I didn't have any choice.

Scott

You should be fine as long the scion looks good. I was just done grafting a week ago [bark graft].
The longest I've ever held over viable scion was from October to May. I'm a late grafter, a bit later is better then too early for me.

Konrad, your June is like our May as far as how far the season is along. I don't have problems with bark grafts in May here, its more June and later. Maybe our 90s - 100s weather this time of year is baking bark grafts too much, but its easier on bud grafts which are on more actively respirating wood. Any time temps are above 90F graft success is at risk.

Scott

Tbud is my favorite if you have the bark and thinner scions. It's worked well so far. also cleft grafts where you splt the stem/trunk and insert at a slight angle ensuring cambium contact. There's a jolly bearded british guy on you tube I recommend. You can't miss him!Do a search and you'll find his videos quite useful.