We bought a 2-in-1 plum tree about 4 years ago. It's half damson and half greengage, grafted on to one rootstock.
It has grown well but stubbornly refused to flower at all. It's nota pollenation problme, there simply are no flowers.Then this year it produced two tiny flowers together. One of these has set, so we are looking forward to our first plum!
I still don't know what we're doing wrong, I gave it a good feed of potash early in the year. I've pruned it a bit now, but am not sure whether I've done this right. If anyone has any ideas on how to encourage it to blossom, please tell me!