Potamogeton bicupulatus, commonly known as Snailseed Pondweed, Fennel Pondweed, or Two-Cup Pondweed, is a deciduous perennial herb that thrives in a variety of freshwater habitats, including lakes, ponds, slow-moving rivers, and canals. It is native to temperate and boreal regions of Eastern North America. This aquatic plant typically grows at a moderate rate to a height of 1-3 feet (0.3-0.9 meters) and spreads to form dense underwater beds. The leaves are submerged and floating, with the floating leaves being more elliptical. Snailseed Pondweed has small, green, inconspicuous flowers that bloom in the summer, followed by translucent, beaked fruits that are sometimes mistaken for seeds by the casual observer.

In cultivation, Snailseed Pondweed is valued for its ability to oxygenate water and provide habitat for aquatic wildlife. It is often used in water gardens, ponds, and for natural water treatment systems. This plant does best in full sun or part shade and prefers very slow draining clay or loam soils, with high or very high amounts of water. While it is generally low-maintenance, it can spread in some conditions, outcompeting native species. To prevent this, management may be necessary to control its spread.CC BY-SA 4.0