SedgeHammer Plus is the go-to control for nutsedge, the glossy, fast-growing imposter that outruns your lawn in summer. The packet contains halosulfuron with surfactant already included: mix one packet in a gallon of water to treat about a thousand square feet of yellow or purple nutsedge without harming most established lawn grasses.

Spray when sedge is actively growing, and hold off mowing for a couple of days before and after so the spray has leaf surface to work with. It moves slowly and systemically, so expect gradual yellowing over one to two weeks as it reaches the tubers.