Proc. Amer. Acad. Arts 15: 48. 1879 ,.
Shrubs, to 2.5 (–5.5) m, rhizomatous. Stems: bark smooth to vertically furrowed, shredding; twigs sparsely to moderately scattered, multicellular stipitate-glandular-hairy and eglandular-hairy (hairs unbranched), also unicellular-hairy, glabrate in age. Leaves deciduous; petiole multicellular eglandular and stipitate-glandular-hairy and unicellular-hairy; blade elliptic to obovate, 2.3–17 × 0.8–5.5 cm, thin, membranous, margins entire or undulate, plane, widely scattered to densely eglandular-hairy, apex acuminate, abaxial surface scattered stipitate-glandular-hairy, adaxial surface scattered stipitate-glandular-hairy and eglandular-hairy, especially near margins. Floral bud-scales glabrous or nearly so abaxially, stipitate-glandular-hairy, often also unicellular-hairy along margins. Inflorescences 5–15-flowered; bracts similar to bud-scales. Pedicels 5–26 mm, stipitate-glandular-hairy. Flowers opening before development of leaves, erect to horizontal, fragrant; calyx lobes 0.3–8.5 mm, glandular-ciliate, often also scattered, stipitate-glandular-hairy; corolla pale to deep pink, sometimes white, with orangebrown or red spots on upper lobes, widely campanulate and appearing ± 2-lipped due to more extensive connation of 3 upper lobes and 2 flaring, slightly longer lower lobes, 18–37 mm, glabrous on outer surface, petals connate, upper lobe 10–18 mm, lateral lobes 14–24 mm, lower lobes 15–30 mm, tube gradually expanding into lobes, 3–8 mm (to 1/4 as long as lobes); stamens (5–) 7, not or only slightly exserted, ± unequal, 12–38 mm; filaments glabrous. Capsules borne on erect pedicels, 9–17 × 3–6 mm, very sparsely to moderately multicellular stipitate-glandular-hairy. Seeds with ± stellate-globular tails; testa tightly appressed. 2n = 26.
Phenology: Flowering spring.
Habitat: Montane bogs, rocky summits, heath balds, steep slopes in deciduous or coniferous forests
Elevation: 900-1800 m
Rhododendron vaseyi is widely cultivated because of its beautiful flowers.