Ortho GroundClear Weed & Grass Killer Spray, 24 oz. is a fast-acting formula designed to kill weeds and unwanted grasses quickly, with visible results in as little as 15 minutes. This powerful weed killer effectively controls a wide variety of weeds including chickweed, algae, dandelion, ragweed, shepherd's purse, moss, mustards, oxalis, and many others. It also targets grasses such as large crabgrass, annual bluegrass, wild onion, and perennial ryegrass. I for use at any time of the year, this landscape weed control works when weeds are small—3 inches tall or wide—and actively growing. It can be safely applied to walkways, driveways, landscape beds, and areas under trees. Treated weeds will change from green to brown within 1 to 2 hours, providing fast and reliable results to keep your outdoor spaces clear and well-maintained.