Carex socialis #1 (Social Sedge)

Social Sedge, also known as Low-Woodland Sedge, is a fine-textured, light-green perennial that favors seasonally wet sites in open woods. It can tolerate drier conditions and drought once established, and favors heavy clay soils. Its tendency to form large colonies by rhizomatous spread gives it its common name. The fine texture of the leaves and the bright green color are similar to Carex pensylvanica, but this species is a better choice for wet, clayey situations. It can be planted to help with erosion control.

Sources:
Lady Bird Johnson Wildflower Center
New Moon Nursery