Stuckenia pectinata aka Comb Pondweed

Stuckenia pectinata is a water plant that lives for years. It belongs to the Potamogetonaceae family. People call it sago pondweed or fennel-leaved pondweed. Older works may use the name Potamogeton pectinatus. It is native to much of the world, including Britain. It grows in ponds, rivers, canals, and ditches. It prefers water rich in bases, not acid sites. Its form can vary within this one species.

This plant has soft stems and grows from rhizomes. These stems lie beneath the water. Stems reach about 3.3 feet [1 metre] in length. The listed garden spread is about 1 foot [0.3 metres]. Few branches grow near the base of each stem. More grow near the top. Most of the plant stays below the water surface. Its flower spike rises above the water. Water moves pollen from flower to flower. Plants do not bloom every year. It crosses freely with other plants in its genus. These crosses often yield sterile offspring, which cannot breed.

Give this pondweed full sun and a mix based on loam. It also grows in sand, clay, and most pond-bottom materials. It suits water that is neutral or alkaline. It can cope with high salt levels, too. Its habitat includes water less than 8.2 feet [2.5 metres] deep. It prefers still water or a slow flow. Each year, plants can live without standing water for up to three months. The listed USDA hardiness range is zones 4–10. It grows fast and needs checks to keep its spread in bounds.

Sago pondweed adds oxygen to pond water. Ducks and other water birds eat it. It takes up phosphorus, which may help curb phytoplankton blooms. Its stems soften waves and can help curb bank erosion. Researchers can use it to track heavy metals in rivers. But its strong growth can crowd out other water plants. It can become invasive in some regions and habitats. Thick growth can clog canals that carry water to crops. It can also cause problems in waters used for leisure.

Records list the leaves, stems, and roots as edible parts. The roots hold starch and taste like nuts. Some accounts say to peel the roots before use. Others call for thorough cleaning and cooking. Local people have also used wild plants as medicine. One record describes a decoction, a liquid made by boiling the plant. People used it for liver complaints with fever. The sources list no known hazards. But they do not show that the plant is safe for all uses.