a tall valerian (Valeriana officinalis) with small, very fragrant, white, pink, or lavender flowers and a strong-smelling root formerly used in medicine
See garden heliotrope in American Heritage Dictionary 4
noun
A widely cultivated valerian (Valeriana officinalis) having clusters of small, fragrant, purplish, pink, or white flowers and strong-smelling rhizomes formerly used in medicine.