Riesenrhabarber in Trebah Gardens, Cornwall

Gunnera manicata, known as Brazilian giant-rhubarb or giant rhubarb, a native to South America from Colombia to Brazil, is a species of flowering plant in the Gunneraceae family.
Gunnera manicata, Devon, England
It is a large, clump-forming herbaceous perennial growing to 2.5 m (8 ft) tall by 4 m (13 ft) or more. The leaves of G. manicata grow to an impressive size. Leaves with diameters well in excess of 4 ft (122 cm) are commonplace, with a spread of 10 ft (3 m) by 10 ft (3 m) on a mature plant. The underside of the leaf and the whole stalk have spikes on them. In early summer it bears tiny red-green flowers in conical branched panicles, followed by small, spherical fruit. However, it is primarily cultivated for its massive leaves.
This plant grows best in damp conditions e.g. by the side of garden ponds, but dislikes winter cold and wet.
It has gained the Royal Horticultural Society's Award of Garden Merit.
Despite the common name, this plant is not closely related to rhubarb. Q: Wikipedia