Hi @gfsheard,
A warm welcome to the Bunnings Workshop community, it is fantastic to have you with us.
I'd suggest using Amgrow Sedgehammer Lawn Herbicide.
It is designed to control nutgrass and mullumbimby couch in various turf varieties, including couch, bent grass, buffalo, and kikuyu.
It targets these persistent weeds without harming your lawn, ensuring a healthier and more uniform appearance.
Remember to wear gloves, long protective clothing and a mask while applying the herbicide and keep people and pets off treated areas until the spray solution has dried.
Let me know what you think and if you have further questions, please don't hesitate to ask.
Jacob
