We grow beach plums in Minnesota - zone 4a sand plains. In our climate they look and taste similar to our
wild american plums - but....they are WAY smaller. Short little babies. Our American plums can get up to 15 feet tall - most being around 10ft. The beach plums seems to top out at 3 feet or so.
Jason Hernandez is correct - coyote (and bear) scat is loaded with wild plum seeds. I have not seen them "digested" or otherwise opened in the scat, but they do come out whole. In our experience, it can take cold 2 seasons (cold/hot/cold) for a plum seed to germinate, but we do not open the pits to free the seeds.
All of these native plums are worth growing. They are cold hardy, drought tolerant, and tasty.
Duffymeadows.com