Pre-emergent Herbicide Overapplication: Not the Solution

Q: Putting down pre-emergent on landscape beds every six weeks isn't working. Should I apply monthly?

A: Pre-emergent chemicals control weeds from seeds (crabgrass, annual bluegrass) but not weeds sprouting from roots (wild violet, onion, bermudagrass). If applied at the recommended rate and watered in, there's no need to apply more often than the label instructs. Over-application may harm existing grass. Sometimes hand-pulling weeds as they appear is the best solution.