hododendron simsii is native to East Asia, where it grows at altitudes of 500?2700m (1600-9000 feet). It is a shrub that grows to 2m (6.5 feet) in height, with leaves that are ovate, elliptic-ovate or obovate to oblanceolate. Flowers range from white to dark red. Rhododendron simsii is of the two species of Rhododendron that can be grown as indoor plants. Rhododendron simsii grown indoors are almost invariably hybrids of mixed parentage and are all small shrubs rarely more than 45cm (18 inch) in height and spread and they have 2-3cm (0.8-1 inch) long leathery, generally egg-shaped leaves. Funnel-shaped flowers are borne at the ends of the stems.
Potted Rhododendron simsii in bud or bloom should be placed in bright light but out of the direct sunlight. When not flowering, they do best if given only medium light, as at a sunless window, although a brightly lit position in a cool room is also suitable. Keep these plants in as cool position as possible, preferably 7-16?C (45-61?F). If the Rhododendron simsii are brought into warm rooms ? above 20?C (68?F) ? the roots will dry quickly, flower will flop and leaves will fall. Move the plants gradually from cool into warmer positions if absolutely necessary, but flower will last longer if they are kept cool. To make sure that indoor grown Rhododendron simsii are permanently moist at the roots (they are almost always potted in pure peat moss) water them plentifully, giving enough at each watering to keep the potting mixture thoroughly moist. They dislike lime, so use soft, lime-free water.