Poastcan be sprayed around them to kill the grasses, but if you use glyphosate (Roundup) to kill the broadleaf plants/trees...as well as the grasses, etc...surrounding the sawtooths, I'd give at least a 5 foot buffer around them. I've seen people get right up to them with it and not hurt them as long as they didn't spray it on the trees, but I would not take that chance myself.