Answer: If the trees look otherwise healthy, my question to you is - do they flower? If not, they will not produce fruit. If they do flower but do not produce fruit it can be due to lack of pollination or that you have ornamental plum trees rather than fruit bearing trees. It would help to know the varieties of plum trees you've planted. With the name we can determine whether that variety will produce fruit in your gardening region. Wish I had more to offer.
Q&A Library Searching Tips