It is a twiggy evergreen or semi-evergreen shrub growing to 2 m (6.6 ft) in height, with leaves that are ovate, elliptic-ovate or obovate to oblanceolate, 1.5–5 by 0.5–3 cm in size.

Some varieties of Rhododendron simsii are poisonous due to the presence of grayanotoxin.

It is also distributed in Areas south of Yangtze in China as well as in Vietnam and Thailand.

[2] The specific name simsii commemorates John Sims (1749-1831) who was the first editor of "Magazine Botanique".

[3] This slightly tender species is quite rare in the west, though well known in Chinese gardens.