Pest grasses range in size, from the tall and tufted pampas grass, to shorter grasses like Mexican feather grass. Grasses can form dense covers that exclude all other plants.
Spraying is the best option for controlling low grasses. Herbicides are available that kill only grasses, and won't damage other plants.
Pull or grub treatment
Only pull or grub out grasses if you have something to replant in their place, or you are able to go back and control other weed species coming through.
Use a spade or grubber to remove the main root mass, shake off any soil, and leave the roots exposed to die.
Revisit the site regularly to pull or grub any grass re-growth.
Note: Just cutting grasses won't work because the growing points of grass are too close to the ground to reach.