I've found that the clovers go dormant at some point anyways even in the wet areas. I'm sure there will be some exception but for the most part you're not going to be growing lush clover plots down here in the south during late July...August....during the heat of summer. That's why it doesn't bother me to let other stuff take over as the summer goes on. I need to produce the biomass and if I sprayed it all out trying to grow clover only, then I'd likely end up with a pretty bare, crunchy field toward summer's end.