I have a plumcot tree app. 8 yrs. old. Rarely do I get any more than 2-3 fruits per year. It is planted next to a Mariaposa plum I also have a Trevat apricot and several other fruit trees, all of which bear heavily. I have even gone and got some branches of another apricot without any success.
Plumcot Not Bearing
Well, since you have several other fruit trees that are bearing well, apparently the problem is not light, fertilizer, pruning or moisture related. And 8 years should be old enough to start bearing. Are you sure this variety is properly suited to your climate? Sometimes a hybrid tree has different requirements than others in its species. The other thing is pollination. In my research, I found that plumcots are not very attractive to bees. Some people have grafted limbs from plums or apricots right into the body of the plumcot tree. Make sure the scions flower at the same time. Another thing that people have tried is to cut limbs from any trees flowering at the same time, and place them into vases of water in or under the plumcot. The idea is to attract the bees to forage in the plumcot. If your interested, here's more info on grafting: https://www.gardeningknowhow.com/ornamental/trees/tgen/grafting-trees-what-is-tree-grafting.htm