Roundup For Lawns Southern RTU Refill 1 GAL. For use on Southern grasses - use with confidence on Floratam. Kills weeds not the lawns. Destroys the hard-to-kill lawn weeds like dollarweed, dandelion, clover and yellow nutsedge - all on one formula. Kills over 90 types of weeds. The fastest lawn weed killer ever-starts working immediately. Kills the root. Guaranteed. Active Ingredients: 2,4-D, Penoxsulam, Dicamba, Sulfentazone.