Monkey grass can be killed with Roundup or other liquid systemic herbicides containing the active ingredient glyphosate, which works by entering the plant through its leaves and disrupting proteins essential for growth. Because Roundup is a non-selective herbicide, it should be used with caution in areas where it might contact desirable plants.
It is best applied in the early spring before the active growth period. Roundup or other liquid systemic herbicides containing the active ingredient glyphosate can be used to kill Monkey grass.