For several years of dog walks, I watched after road mowing crews mowed off the side of a large feral black cherry growing in the county roadway easement. When I could access the cherries, they were delicious and different from the usual sweet cherry, black and with a "black cherry flavor".
I salvaged some sticks and grafted to a sour cherry (I think North Star?') that wasn't mature yet, headinf there. I thin that was two, but maybe three, years ago.
Here are those black cherry branches now.
They are much more vigorous compared to the sour cherry tree. The big tufts of flowers, are the feral black cherry. The more sparse flowers are the sweet cherry.
I think I can prune back the black cherry about 1/2 after they bear. There are some sour cherry wild seedlings in the duck yard - maybe I can graft onto those, and try to preserve the original sour cherry.