How To Get Rid Of Nutgrass In Your Lawn Using [Sempra Herbicide] And Your Local [Lawn Spraying Service]. In this video we have a look at a client’s lawn in the Lower North Shore suburb of Cremorne. Nutgrass and Mullumbimby Couch are both sedge type weeds and are both targeted successfully with [Sempra] or [Sedgehammer] herbicides (both with the same active constituent). Sempra and Sedgehammer are herbicides that can selectively remove Nutgrass and Mullumbimby Couch from just about all turf grasses including Buffalo (Stenotaphrum secundatum), Couch (Cynodon dactylon), Kikuyu (Pennisetum clandestinum), Zoysia (spp), Queensland Blue Couch, etc. Generally these weeds are found in lawns that are too moist in the upper zone of the soil.