Spectracide One-Shot Weed and Grass Killer Concentrate2 works fast to kill unwanted weeds and grasses. This powerful formula kills from the leaves to the roots and prevents regrowth for up to five months. Plus, it works quickly, with visible results same day. Clear out unwanted vegetation on walkways, driveways and patios. Avoid spraying this product onto desirable plants, lawn grasses, shrubs or trees. Spectracide One-Shot Weed and Grass Killer Concentrate2 gives you control over weeds and grasses, roots and all.