Make troublesome lawn weeds a problem of the past. Roundup For Lawns is a ready-to-use tough weed killer for Northern grasses that kills weeds, roots and all (when used as directed), with up to 3 month weed control (as listed). This product kills 253 types of weeds (see inside booklet for weed list), including crabgrass, dandelion, clover, yellow nutsedge, poison ivy, chickweed, oxalis, and purslane. In addition, it starts working immediately and is rainproof in 3 hours.