The 4% Atrazine Weed Killer 1 Qt is a selective herbicide formulated specifically for warm-season lawns. It delivers reliable control of broadleaf and grassy weeds, including crabgrass, in St. Augustine and Centipede grasses, while allowing these turf types to thrive. With a 4% atrazine formulation, it targets both emerged weeds and weeds germinating from seed, making it ideal for preventive and postemergence weed control.