I tried my hand at grafting a couple of years ago. It didn't go well. I used a tool to cut the stem (V Graft) and wrapped it with opsite tape. None made it. Wondering what I did wrong? I tried to choose branches of similar diameter, and did my best to wrap the branches nice and tight. Is there a better time of the year to do the grafts? Any tips would be welcome. I've got larger yellow white trees that I'd like to graft some colors onto.

Thank you!

I'm just bumping this to the top to see if anyone has any good tips?

Try slant grafts instead. Try to use woody, older branches. Use zip ties to hold in place. Best time is early to middle of the growing season. Don't have the graft in full sun. If so, cover with a layer of foil. There's a ton of videos on YouTube that can guide you in the right direction. Grafting is hit or miss. Got a 50/50 chance of success. Good luck next time.