Roundup, 1.25 Gallon, Weed & Grass Killer Refill, Kill the toughest weeds and grasses down to the root with Roundup Ready-To-Use Weed & Grass Killer III refill. The formula is ideal for use in and around vegetable gardens, flower beds, tree rings, and mulched beds, as well as on cracks in driveways, walkways, and patios. Simply pour into your any Ready-To-Use Roundup Weed & Grass Killer III applicator and kill weeds faster with Roundup.