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How to Kill Dune Grass

Several different grasses are commonly called dune grass. All of them are very invasive and extremely hard to kill. If not killed dune grasses will spread, mainly by rhizomes (roots which grow new grass) until it has taken over almost every square inch of your yard.

Dune grass is tolerant of poor soil and even salt. Killing dune grass which has already grown among your other grass or plants may require the elimination of those grasses and plants as well.

Spread a black tarp over your dune grass and weigh down the edges of the tarp so it stays in place. Leave the tarp over the grass for 14 days. Dune grass is a sun-loving grass and depriving it of light kills its leaves and weakens its root system.

Remove the tarp and rototill the soil, exposing as many of the roots as possible. Use a hard-tinned rake and/or shovel to dig up as many of the roots as you can. Burn or dispose of the roots.

Watch carefully for new dune grass plants to emerge. When they do, spray their leaves immediately with Roundup. Wait 7 days and then dig down and remove the roots of the dune grass which has been killed by the Roundup.

Be vigilant. Continue to spray all new dune grass growth with Roundup and then dig up the roots. Ridding your yard of dune grass can be a two-season project.

Kill Bad Grass

Spray actively growing grass with a grass killer, such as the non-selective herbicide glyphosate. Apply it only when the weather is not windy and when rain is not expected for the next two days. Reapply the grass killer to live patches if necessary. Pick up the resulting clumps of grass, shake off the soil and discard the clumps. An option is to rake away the grass. Cover the unwanted grass with six layers of cardboard, then cover the cardboard with 4 to 6 inches of mulch, such as leaf mold. If desired, punch holes in the cardboard and plant mature plants in soil beneath the holes, but watch for grass that may sneak through the holes. Pull that grass to remove it. Mow the grass with a lawnmower set at its lowest cutting height and during the hottest time of the year. For other areas of the landscape, use a weed trimmer to cut the grass short. Water the cut grass with 1 inch of water. During that time, the grass underneath the tarp will die from the excess heat created by the tarp and weather.

Tip

Be persistent. Dune grass is very resilient and will grow if even one good root remains underground. Continue spraying with Roundup and digging up roots.

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