Description from Flora of China
Rhododendron bhotanicum C. B. Clarke.
Shrubs, often epiphytic, 1.5–3 m tall; sparsely branched; young shoots scaly. Petiole convex, 15–20 mm, scaly; leaf blade thinly leathery, ovate-lanceolate, or narrowly elliptic, 6–15 × 1.5–5.5 cm; base cuneate or rounded; apex rounded; abaxial surface pale white, scales 2–3 × their own diameter apart, variable in size; adaxial surface deep green, sparsely scaly. Inflorescence terminal, umbellate, 4–6-flowered. Pedicel 1–1.5 cm, densely brownish red scaly; calyx lobes 1–5 mm, oblong, persistent and surrounding base of fruit, scaly at base; corolla broadly tubular-campanulate, white, 7–8 cm, outer surface scaly at base; stamens 10, filaments pubescent below; ovary 5-locular, densely reddish brown scaly; style base scaly. Capsule ca. 50 mm, not keeled. Fl. Apr–May.
Forests, sometimes epiphytic; 1600–2900 m. Xizang [Bangladesh, Bhutan, N India, Myanmar, Nepal, Sikkim].