Welcome to this forum, Jspence 42.
I don't think you need to worry about the Black Cohosh, unless it is just everywhere. I have a section of Black Cohosh growing in one of my patches, and the plants seem to get along fine. It is a marketable plant as well.
If you end up cutting it back to makle rrom for your 'sang, then be sure you dig out the roots where you are cutting it back...
good luck on it!