'great willow herb' definitions:

Definition of 'great willow herb'

From: GCIDE

Rosebay \Rose"bay`\, n. (Bot.) (a) the oleander. [Obs.] (b) Any shrub of the genus Rhododendron. [U.S.] (c) An herb (Epilobium spicatum) with showy purple flowers, common in Europe and North America; -- called also great willow herb. [1913 Webster]