plum fruit falls off before ripening

by diana
(worcesterm ma.)

My plum trees get plums every year but they all fall off when size of prunes and are hard. I have 18 fruit trees and 3 are different plums, all different varieties to pollinate each other. They are approx. 8' apart.

Doug says that fruit drop is normally a symptom of stress of some kind. Usually water or other phyiological; sometimes insect infestation.

Plums also drop fruit (that looks small) when the fruit wasn't successfully pollinated.

Plums tend to do it a little bit faster and easier than other trees in my experience