Description Use Ortho GroundClear Weed and Grass Killer Super Concentrate1 to kill 175 different weed and grass types including crabgrass, dandelion, nutsedge, and oxalis. The quick-kill, dual-action formula starts working immediately. One ingredient kills on contact while the other penetrates deep into the plant to kill all the way down to the roots. Sprayed weeds usually begin to wilt within hours after being treated, with weeds completely killed in 1 to 2 weeks. Apply this powerful weed and grass killer around landscape areas, patios, walkways and driveways. A single application controls most listed weeds. Rainfall or watering 15 minutes after application will not reduce the effectiveness of this powerful weed control. Easily apply to weeds and unwanted grasses with an Ortho tank sprayer. When mixed as directed, each 32-oz. bottle of concentrate creates 6.4 gallons of weed and grass killer to treat up to 2,240 sq. ft.