Gunnera manicata, known as Brazilian giant-rhubarb[1] or giant rhubarb,[2] is a species of flowering plant in the family Gunneraceae from the coastal Serra do Mar Mountains of Santa Catarina, Parana and Rio Grande do Sul States, Brazil.

In early summer it bears tiny red-green, dimerous flowers in conical branched panicles, followed by small, spherical fruit.

[7] Gunnera manicata is native to the Serra do Mar mountains of coastal Santa Catarina and Rio Grande do Sul states, Brazil, where it is used in traditional medicine for sexually transmitted diseases.

[8] Giant rhubarb came to be widely cultivated in the United Kingdom and Ireland as an ornamental garden plant.

[5] In December 2023, the UK Department for Environment, Food and Rural Affairs banned Gunnera × cryptica: it cannot be sold or cultivated, and those who have it in their gardens must ensure it does not spread.