Image Crabgrass, Nutsedge, & Weed Killer for Lawns Concentrate kills the weeds, not the lawn. This dual action formula starts working on contact to kill even tough weeds to the root. Use on established lawns to control annual grasses, broadleaf weeds, and sedges. This water based formula starts working immediately and won't harm your lawn when used as directed. This product can be used to control weeds in southern and northern turfgrasses including Fine & Tall Fescue, Perennial Ryegrass, Kentucky Bluegrass, Bermudagrass, Centipedegrass, and Zoysia. Use when weeds are small and actively growing. For best performance, apply when temperatures are between 55 Deg F to 85 Deg F. This product kills Sedges, Crabgrass, Dandelion, Clover, Dollarweed, Spurge, and other listed weeds.