Cyperus lancastriensis, with no widely recognized common name, is a perennial herbaceous plant belonging to the sedge family. It is native to wetlands, marshes, and along the edges of ponds and streams in the eastern United States. This sedge typically forms dense clumps and can reach heights of 1-3 feet (0.3-0.9 meters). Cyperus lancastriensis has a grass-like appearance with triangular stems and umbrella-like clusters of narrow, greenish-brown spikelets at the top. It does not produce showy flowers, as is characteristic of many sedges, and its flowering season extends through the summer months.

Cyperus lancastriensis is valued for its ability to stabilize soil and filter water, making it useful for erosion control and in rain gardens. It is also used in naturalized plantings and as a ground cover in wet areas. This sedge prefers full sun to part shade and thrives in wet, boggy soils with poor to moderate drainage. While it is low-maintenance and can be an asset in water gardens or naturalized areas, Cyperus lancastriensis can become aggressive in favorable conditions. It is important to monitor its spread to prevent it from becoming invasive outside its native range.CC BY-SA 4.0