what causes developing santa rosa cherries to fall?

Question

Original tree purchased 15 years ago at Big Lots, It was in a pot. . . overgrew the pot and grew into a tree. After about 4 years plums developed and ripened. Then, the tree started flowering, but tiny plums would drop off. A few may remain to grow, but not ripen. Even the few remaining fall prior to ripening.

Another Spring is fast approaching. There will be lots of beautiful flowers which last briefly, then drop of flowers and what may have been developing fruit.

Answer 1

You may be having pollination problems, but a trip to your local extension office or nursery may be in order. This article should help:

https://www.gardeningknowhow.com/edible/fruits/plum/plum-trees-not-fruiting.htm