I could not find an answer to the following: a neighbor's landscaper applied some heavy duty weed killer on our round raised bed with azaleas (approx. 6' diameter) that is surrounded with rocks. I do not appreciate any weed-killing chemicals, can do it by hand without them. Are there known ways to flush out or neutralize a strong weed killer already in the ground and on the surrounding rocks? (don't have the name of the product he used, but it was strong: every living thing was gone within a week - not sure how the azaleas will do)