Roundup Poison Ivy Plus Tough Brush Killer ConcentrateRoundup Poison Ivy Plus Tough Brush Killer Concentrate is an exclusive formula that kills poison ivy, poison oak, poison sumac, wild blackberry, kudzu, and all types of tough weeds. It is rainproof in as fast as 30 minutes, produces visible results in hours, and allows you to plant 1 to 30 days after application. Use this weed control in residential fields and trails, around trees or shrubs, around homes, buildings, cabins, lodges, and camp sites,