Bonide Poison Oak & Ivy Killer RTU uses the effective herbicide Trimec (a combination of 2-4,D; Mecropro-p; and Dicamba) to kill Broad-leaf weeds to the roots. Bonide Poison Oak & Ivy Killer RTU works systemically and travels throughout the plant with results becoming apparent after a few days. Bonide Poison Oak & Ivy Killer RTU becomes rain fast after drying - do not water for 24 hours after treating.