This product contains a proven blend of three weed killers to kill existing weeds PLUS a residual herbicide to keep them from coming back for up to six months. Weeds begin to wilt and die within hours and are completely dead in 14 – 28 days. And it won’t harm your lawn when used as directed. Offers up to 6 months of control with only 1 application. Proprietary 2-in-1 formula. Post-Emergent: Kills existing broadleaf weeds. Pre-Emergent: Prevents new broadleaf weeds for up to 6 months (Does not provide pre-emergent or post-emergent control of Crabgrass; see product label for kill/prevent weed list). Won’t harm lawns (when used as directed). Do not use on Carpetgrass, improved varieties of St. Augustinegrass including Floratam, Dichondra or desirable clovers). Apply anytime, Spring or Fall. Rainproof in 1 hour. The treated lawn can be mowed one to two days after spraying. Clippings from the first three mowings should be left on the treated area. Do not use clippings from the treated areas as mulch or compost around flowers, ornamentals, trees or in vegetable gardens. If lawn is dry, water one to two days before using this product. Rain or watering one hour after application will not wash away effectiveness.