I am doing more and more bed jobs this year and have came across a couple beds that need the edge line redefined. What are some good techniques for the removal of whats in the existing beds (like mulch, weeds, and grass from improper edging)? Last year we just used edgers and action hoes to remove the grass that had ran into the existing beds. I know with pine straw you cant leave the weeds and grass. Can you leave the weeds and grass and just spray with roundup then put mulch over and just define the edge line?