Several years ago I planted a large monkey grass patch to keep the area where the storm sewer empties from eroding. Worked great, but now it is very thick and full of grass. How do I thin it and how do I get rid of the grass and keep it out? Thanks.
Certified GKH Gardening Expert
I would recommend pouring boiling water on the areas where the unwanted grass is growing. Boiling water will kill whatever it comes in contact with, but you'll have to protect the monkey grass. Alternatively, you could cover monkey grass clumps with cardboard boxes or use a gallon milk jug with the bottom cut off as a shield. Spray the grass with an herbicide during hot weather when the grass is actively growing. One application won't work, as it's going to take several. If a little herbicide touches the monkey grass, don't despair. It will only kill the little sprout, not the clump. Finally, you can use the old standby--hand pulling all the unwanted grass. If hand pulling is not viable, you can try using Ortho Weed-B-Gone. This will kill the grass but not harm the monkey grass.