I'm not sure what you mean, Berger. I've never tried to root wild black cherry/Prunus serotina, since they come up all over the place from seeds. I've got two in containers now that I dug up this past spring when they were only inches high. I'll keep them in containers for as long as possible, unless I learn bonsai! :)
I've never had any trouble finding caterpillars on wild black cherry on the branches within my sight. Finding them on the tall trees is impossible - they make a big tree, with the lowest branches being way above my head, even on a tall ladder.

If you can't find any local seedlings to dig up, you can ask for somebody to send you some seeds next year. WBC is a fast grower.

Sherry