Richard,
I've had a couple of seedling beach plums, from OIKOS, growing here for
nearly 10 years. One is just about dead now, as the neighbors re-did their
septic leach field, and it's virtually drowned, as a result. Small, tart
fruits, low pulp:pit ratio, almost 'dry', and they do dry up on the bush,
almost like raisins. Better/larger than a Nanking cherry.