Description from Flora of China
Azalea mucronata Blume, Catalogus, 44. 1823; A. indica Linnaeus var. alba Lindley; A. rosmarinifolia N. L. Burman; Rhododendron argyi H. Léveillé; R. ledifolium G. Don; R. rosmarinifolium (N. L. Burman) Dippel (1889), not Vidal (1886).
Shrubs, semievergreen, 1–2(–3) m tall; young shoots spreading; branches many, densely gray-brown villous, also with a few glandular hairs. Summer and winter leaves different. Petiole 2–4 mm, densely long-strigose, hairs flat, and shortly glandular-hairy; leaf blade papery, lanceolate to ovate-lanceolate or oblong-lanceolate, 2–6 × 0.5–1.8 cm; base cuneate; apex obtuse to rounded. Inflorescence 1–3-flowered. Pedicel to 1.5 cm, densely yellowish brown-villous, also glandular-hairy; calyx lobes 5, lanceolate, ca. 12 mm, densely glandular-pubescent; corolla broadly funnelform, deeply 5-lobed, white, occasionally pale red, without purple flecks, 3–4.5 cm, lobes elliptic-ovate, as long as tube, glabrous; stamens 10, unequal, filaments puberulent below; ovary ovoid, ca. 4 × 2 mm, 5-locular, densely coarsely appressed-glandular-setose; style very long-exserted, glabrous. Capsule conical ovoid, ca. 10 mm. Fl. Apr–May, fr. Jun–Jul.
This species was described from a cultivated plant that may represent an albino form of the Japanese Rhododendron mucronatum var. ripense (Makino) E. H. Wilson; the latter differs in having rose-pink flowers.
Cultivated in many places in E and S Sichuan and in many parks in China. Fujian, Guangdong, Guangxi, Jiangsu, Jiangxi, Sichuan, Yunnan, Zhejiang [of cultivated origin].