Eleocharis interstincta, commonly known as Knotted Spikerush, is a perennial herb that is evergreen in warmer climates. It is native to wetlands, marshes, and the edges of ponds and streams in Florida, the Caribbean, Mexico, and Central and South America. This sedge typically grows to a height of 1-4 feet (0.3-1.2 meters) and a width of 1-3 feet (0.3-0.9 meters), forming dense clumps of grass-like foliage. The plant features small, inconspicuous brownish flowers that appear on the tips of the stems, primarily during the warm season.

Knotted Spikerush is valued for its ability to stabilize soil and filter water, making it an excellent choice for water gardens, rain gardens, and naturalized wetland areas. It is also used for erosion control along waterways. In cultivation, it requires full sun to light shade and thrives in wet to saturated soils, often with standing water. It is a low-maintenance plant that can spread to form large colonies if conditions are favorable. While it is not known for significant pest or disease problems, it can become invasive in areas outside its native range if not managed properly.CC BY-SA 4.0