hy·dran·gea / hīˈdrānjə/ • n. a shrub or climbing plant (genus Hydrangea, family Hydrangeaceae) with rounded or flattened flowering heads of small florets, the outer ones of which are typically infertile. Its many species include late (or panicled) hydrangea (H. paniculata), an ornamental shrub, and bigleaf hydrangea (H. macrophylla), commonly grown for florists and as a houseplant.

Hydrangea (family Hydrangeaceae) A genus of erect or climbing, evergreen or deciduous shrubs. The leaves are opposite, the flowers in cymes, often as flat heads and with showy, sterile, marginal flowers. Several species are cultivated as ornamentals. There are 23 species, occurring from the Himalayas to Japan and the Philippines.

hydrangea Genus of 80 deciduous woody shrubs, small trees, and vines, native to the w Hemisphere and Asia. They are grown for their showy clusters of flowers, which may be white, pink, or blue. Family Hydrangeaceae.

hydrangea XVIII. — modL. hydrangēa, f. Gr. hudōr, hudr- WATER + ággos vessel; so called with ref. to the cup-like form of the seed-capsule.