vervain(n = noun.plant) verbena - any of numerous tropical or subtropical American plants of the genus Verbena grown for their showy spikes of variously colored flowers;
vervain, n. [OE. verveine, F. verveine, fr. L. verbena, pl. verbenae sacred boughs of laurel, olive, or myrtle, a class of plants; cf. verbenaca vervain. Cf. Verbena.].
Any plant of the genus Verbena. [1913 Webster]
Vervain mallow(Bot.), a species of mallow (Malva Alcea) with rose-colored flowers.