Don't Pull Weeds and Grasses, Prevent Them! Introducing Roundup® Landscape Weed Preventer which prevents weeds and grasses for up to 6 months! It creates a weed barrier and stops weeds from growing. For best results, apply directly to soil around plants in Spring before weeds germinate and before mulching. And, when used as directed, it won't harm your desirable plants and flowers! The easy to use built-in applicator provides even coverage. Save time and energy with Roundup Landscape Weed Preventer. Outsmart weeds before they appear. A simple step towards a weed free landscape and garden!