That's a great question Coach, most of mine were placed around during excavation because they're so large. I've been filling in the open areas for years now. The weed pulling goes on all growing season. I don't want to use weed killers because I have trout and PS in the pond.
If I could do it over I would have placed a landscape cloth down first, but that may have been fruitless because; The slopes are steep and I'm sure that during excavation it would have been torn anyway.