I think it depends largely on your area. Here in the NW it is often drizzly in the Spring on the west side, so many of these plants don't tend to do well, although I have seen them do quite well in NE Oregon, where it is drier.

Late answer, I know....
I moved to a new rental last year. There are four 5'-6' bushes in the front yard. Imagine my surprise when plums started to develop on them! The kids cautioned me not to eat them, but I contacted the landlord who said people have been eating plums from that bush for 5 years and no one's croaked yet. Tart, but delicious fresh. Haven't tried to do anything more creative with them yet.
He doesn't know the name, but I think they're carissa lanceolata, or at least that's what some research, comparisons to online photos, etc. have lead me to believe. Hope that helps!