any of a genus (Astilbe) of herbaceous, perennial plants of the saxifrage family, usually having spikes of white, pink, or red flowers
See astilbe in American Heritage Dictionary 4
(ə-stĭlˈbē)
noun
Any of various chiefly eastern Asian perennial herbs of the genus Astilbe, having compound basal leaves and showy panicles of tiny colorful flowers. Also called spirea.