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.