azalea [Gr.,=dry], any species of the genus Rhododendron, North American and Asian shrubs of the family Ericaceae (heath family) that are distinguished by the usually deciduous leaves. Azaleas are handsome shrubs with large clusters of pink, red, orange, yellow, purple, or white flowers. The better-known native American azaleas, often cultivated, include the flame azalea (R. calendulacea) of the Appalachians; the pinxter flower (R. nudiflora) and the fragrant white azalea, or swamp honeysuckle (R. viscosa), of the E United States; and the Western azalea (R. occidentalis) of California and Oregon. Most azaleas grow in damp, acid soils of hills or mountains. The rose-purple R. canadense, a rare species with an unusually northerly range (from Pennsylvania to Newfoundland) is the rhodora immortalized by Emerson. Many of the brilliantly flowered garden varieties are native to China and Japan, where the genus is most abundantly represented. The popular Ghent azaleas are hybrids. Dwarf azaleas are grown by florists as pot plants. Azaleas are classified in the division Magnoliophyta, class Magnoliopsida, order Ericales, family Ericaceae.

Any plant of certain species of the genus Rhododendron (heath family), formerly given the generic name Azalea. Though some gardeners consider azaleas distinct from rhododendrons, distinguishing characteristics of the two groups are not consistent enough to separate them into two genera. Azaleas typically are deciduous (see deciduous tree), with flowers that are funnel-shaped, somewhat two-lipped, and often fragrant. Cultivated varieties have been bred from species native to the hilly regions of Asia and North America. Well-known North American kinds include the smooth, or sweet, azalea (R. arborescens); the flame azalea (R. calendulaceum); and the pinxter flower (R. periclymenoides).

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