Roundup For Lawns3 is a tough weed killer for use on northern grasses that kills weeds, not the lawn. This tough weed killer kills 253 types of weeds and works fast on hard-to-kill weeds. It won't harm lawns when used as directed on northern grasses, including bluegrass, fescue, zoysia, perennial ryegrass. The ready-to-spray applicator covers up to 5000 sq-ft, just connect to your garden hose and spray. This product starts working immediately, is rainproof in as little as 3 hr and controls weeds for up to 3 months. Roundup For Lawns3 kills the root so weeds won't come back. Apply Roundup For Lawns3 to actively growing weeds during the early growth stages for the excellent results. Apply in spring or fall when daytime temperatures are between 45 deg F and 90 deg F. Roundup For Lawns3 is a simple step for home lawn care. No weeds. No worry.