Preen Lawn Crabgrass Preventer - 17 lb. 2463694 Prevents crabgrass and other grassy and broadleaf weeds for up to 4 months It also provides post-emergence control of seedlings crabgrass for up to 4 weeks after it germinates Provides season-long control for some of the toughest weeds When used according to the directions, it will not harm nearby established ornamentals 17 lb bag