Gunnera perpensa aka Gunnera Perpensa

Gunnera perpensa has the common name river pumpkin. It belongs to the Gunneraceae family. This herb lives for more than one year. It comes from eastern and southern Africa, including Madagascar. Its range runs from Ethiopia south to South Africa. It grows in swamps and wet grass beside streams. It also grows on cool, damp ground in upland forests. These sites stay wet even in regions with dry seasons.

Garden sources give heights of about 1.3–2.3 feet [0.4–0.7 metres]. A broader plant account reports heights of 3.3 feet [1 metre]. The plant has a creeping rhizome, a stem below ground. This stem forms clumps that gardeners can divide. PFAF gives August as the time when flowers bloom. Male flowers grow at the top of the flower head. Female flowers grow below them. Flowers with both male and female parts grow between them. Wind carries the pollen.

Grow this plant in damp soil rich in humus. It accepts full sun or partial shade. Sandy, loamy and clay soils can all suit it. Soil may be mildly acid, neutral or mildly alkaline. In the wild, it grows in wet soil and shallow water. This makes it a choice for a bog garden. It can also grow along shallow pool edges or streams. Useful Tropical Plants says it cannot survive frost. It may die back in the coldest months, even in sheltered spots.

Grow new plants from seed or divide the clumps. Sow fresh seed in autumn in a sandy mix. Use a cold frame for cover. You can also sow seed in spring. Move seedlings to their own pots when large enough to handle. Keep them under glass through at least their first winter. Plant them out after the last expected frost. Divide clumps when fresh growth starts in spring. Keep small divisions under cover until they root well.

People eat the leaves cooked or chew them. They also eat the leaf stalks raw. Both main use sources report no known hazards. This does not prove safety for every person or pet. Useful Tropical Plants notes use in South Africa's folk medicine. It also notes possible use to repair soil and hold it in place. Wild harvest and wetland loss have cut plant numbers in South Africa. The species still has a global listing of Least Concern. That status does not rule out steep local losses.