Ribbon grass is a relatively easy plant to kill in the home landscape. It is often planted as an ornamental, but if not carefully monitored it can spread outside of its bed. Ribbon grass spreads through underground roots and seeds. Because its roots are capable of regenerating, simply cutting the grass is not enough to kill it for good. To do that, use any number of methods to kill or starve its root system so that it cannot produce any more foliage.
Smother small stands of ribbon grass. In spring, cut the ribbon grass down as low as possible. Water the stand with 2 inches of water. Then spread a sheet of opaque black plastic over the stand. Make sure that all of the ribbon grass is covered. Bury the edges of the plastic 3 inches deep to prevent it from flying away. Leave the plastic in place for one growing season. The accumulated heat and lack of oxygen will kill the stand.
Dig up the ribbon grass. The best way to get rid of ribbon grass quickly is to use a shovel or bulldozer to remove the ribbon grass and the 18 inches of soil that lies beneath it. Discard the uprooted soil and foliage and replace the top soil.
Upturn and mix the ground beneath the ribbon grass to a depth of 18 inches with a shovel. By repeatedly disrupting its roots every 2 to 3 weeks in this manner, you will deplete the ribbon grass' energy stores and eventually it will stop growing back. This may take one to two seasons.
Spray the ribbon grass with a non-selective glyphosate herbicide. In spring, when ribbon grass is actively growing but other plants are dormant, cut the ribbon grass to within a few inches of the ground. Then spray the ribbon grass according to the manufacturer's instructions. Re-spray the ribbon grass as needed at the rate recommended by the manufacturer. The Wisconsin Department of Natural Resources recommends mowing and treating again in mid-September and then in October.
Replant the area once the ribbon grass is gone. This will prevent it from reestablishing itself. Choose a quick-growing native plant or ground cover that will easily establish itself in the area.