I have rocked areas that were not lined with plastic prior to rock being laid down. Every year there are tons of weeds and grasses that I keep pulling out. I'm going to spray with Round-up and then I want to spray with a pre-emergent. Please reccomend a pre-emergent.
Certified GKH Gardening Expert
Preen is a good pre-emergent or you could opt for a more natural choice such as corn meal.