Bolboschoenus fluviatilis aka River Club Rush

Bolboschoenus fluviatilis, or river bulrush, belongs to the sedge family. It is a perennial plant of temperate wetlands. Kew places its native range in eastern Australia and New Zealand. The range also spans North America to northeastern Mexico. Sources also list it as Scirpus fluviatilis and Schoenoplectus fluviatilis. It grows in marshes with fresh or brackish water. It also lives beside lakes and slow streams. Plants can grow in water 3.3 feet [1 metre] deep.

River bulrush has an upright form. Plants reach about 6.6 feet [2 metres] tall. Its roots form tubers at points along their length. These tubers can give rise to new plants. Young tubers are white and rich in starch. With age, they turn black and become woody. They can reach about 0.1 feet [0.03 metres] across. Chicago Botanic Garden lists green flowers from July to August. The flowers have both male and female organs. Wind carries their pollen.

This plant suits pond edges and bog gardens. It needs moist or wet soil and can grow in water. Chicago Botanic Garden lists full sun or partial shade. PFAF reports that it grows in sand, loam, and clay. It also accepts mildly acid, neutral, and mildly alkaline soils. PFAF notes that it can grow in salty soil. Chicago gives a USDA hardiness range of zones 3–9. PFAF does not confirm its hardiness in Britain. Its wider growing notes draw on the needs of the genus.

Peeled stems and roots have recorded food uses. People eat the roots raw or cooked. Young tubers have a sweet taste that recalls coconut milk. Older tubers become woody rather than staying soft and starchy. PFAF gives the plant an edibility score of two out of five. It lists no known hazards, rather than proof of safety. PFAF also records research into possible effects on fertility. That report does not establish a safe medicinal use.

The roots also have a role in basket work. Makers darkened them with mud and ashes for black designs. Chicago Botanic Garden reports that the plant draws birds and butterflies. Gardeners can raise it from seed or divide it in spring. PFAF describes division as easy. Its wetland needs make water-side sites its main garden setting.