Juncus marginatus, commonly known as Margined Rush, is a grass-like herbaceous perennial that is native to a variety of wetland habitats including moist meadows, wet prairies, marshes, and the edges of ponds and streams across North America, particularly in the Eastern and Southeastern US. It typically grows to heights of up to 51 inches, forming dense clumps of upright, cylindrical stems. The inflorescences appear in summer, with flowers that have reddish-brown sepals, and are not particularly showy. The seeds develop in rounded, beakless capsules that are more noticeable than the flowers.

Margined Rush is valued for its ability to stabilize soil and filter water in wetland restoration projects. It is also used ornamentally in water gardens and naturalized areas where its vertical form contrasts with broader-leaved plants. It thrives in full sun to part shade and prefers consistently moist to wet soils of various types, including sandy, peaty, or clayey substrates. While it is generally low-maintenance, it can spread aggressively in ideal conditions. In Minnesota, it is considered endangered due to habitat loss and is protected to preserve its populations.CC BY-SA 4.0