I didn’t know what False Green Kylinga was until four years ago, when we first encountered it out on New York’s Long Island. Once a nuisance seen mostly in the southeast, it’s now the #1 weed plaguing coastal communities up to the northeast seaboard.
False Green Kylinga (Kyllinga gracillima Miq.) is a perennial plant, one of a species of mat-forming sedge. It thrives under close mowing situations (an inch or less) and in areas that are poorly drained or frequently wet.
Before flowering, False Green Kylinga looks like a nice, healthy grass. From May through October the plant develops triangular stalks that terminate in globe-shaped, dense green flower heads, with dozens of spikelets within each flower head. It spreads really quickly, crowding out desirable turfgrass. The weed dies with the 1st frost, leaving behind large dead patches on the lawn.
This weed is tough to control once large mats have formed. Herbicides are effective only on actively growing plants, so applications should be made from May through August. For long-term control, you need to solve the underlying cause of the weed’s proliferation. That means addressing any drainage issues that are causing prolonged periods of excessive moisture.
Bottom line: If you see what you think might be False Green Kylinga, call your arborist immediately so s/he can implement an early and consistent treatment program.