Shrubs, (2.5–)3–4 m tall; branches slender, scaly. Petiole 5–6 mm, densely scaly; leaf blade papery, broadly elliptic, or elliptic, sometimes nearly obovate, 3–7 × 2–3 cm; base obtuse or tapering; apex acute or obtuse, mucronate; abaxial surface pale yellowish green, scales ca. 2 × their own diameter apart; adaxial surface green, sparsely yellowish scaly. Inflorescence terminal or axillary, 2- or 3-flowered. Pedicel ca. 1 cm, densely scaly; calyx lobes distinct, ca. 1.5 mm, scaly, margin scaly and ciliate; corolla tubular, scarlet, ca. 2 cm; lobes 5–6, triangular or nearly ovate, ca. 0.4 cm; stamens 10–12, slightly longer than corolla, filaments sparsely pubescent towards base; ovary densely scaly; style longer than corolla, pubescent toward base. Fl. Jul.

Rhododendron igneum is very close to R. keysii, but differs in the broader leaves, fewer flowers in the inflorescence, and in the slightly longer calyx lobes. It has been treated as a synonym of the latter species by some authors.

Dense mixed forests; ca. 2800 m. SE Xizang.