Any of several large ornamental waterside plants of the genus Gunnera, including G. manicata and G. tinctoria, which have very large leaves borne on spiny stalks.
Origin
Late 19th century; earliest use found in William Robinson (1838–1935), horticulturist and publisher.
Definition of prickly rhubarb in US English:
prickly rhubarb
noun
Any of several large ornamental waterside plants of the genus Gunnera, including G. manicata and G. tinctoria, which have very large leaves borne on spiny stalks.
Origin
Late 19th century; earliest use found in William Robinson (1838–1935), horticulturist and publisher.