gunnera

Giant rhubarb (Gunnera tinctoria, Gunneraceae) is a massive perennial from Argentina and Chile, reaching 5 to 6 feet tall with palmate leaves up to 2.5 meters (8.2 feet) across on spiny stems. Cone-shaped inflorescences up to 1 meter tall and weighing up to 14 kilograms appear from June through August. Despite the common name, it is not closely related to culinary rhubarb.

Giant rhubarb grows in part shade with moderate to high water needs and tolerates wet soil, hardy in Zones 7 to 9. The stems bear thorns. No pest or disease issues and no cultivars are documented.