Just freed a tree from a big mat of Virginia creeper today. Under the vines I thought it was a plum of some type given the bark and branching habit. After exposing the fruit, I have no idea what it is. Can anyone help me? The fruit almost tastes like grapes, with a similar skin and a small pit. Juicy like highbush cranberry. The fruit is in clusters near the base of twigs. Leaves are simple, whitish underneath (visible on a water sprout in the trunk pictures). I suspect it was planted as a fruit tree as it was initially espaliered, but hasn't been maintained for many years. Sorry for the awful photos...
Thanks Susan, That is it! I see it is invasive in some areas but doesn't seem to be here. A good nitrogen fixer and edible, healthy fruit. I think I'll try to grow some cuttings.