Some tropical varieties are epiphytic (ie Vireya). Vireyas are cold sensitive types, mostly native to the tropics.
Many will however still grow in colder climates if protected from frost.
Vireya varieties need protection from temperatures above 250C and below 80C.
Foliage us normally glossy green. Most are small to medium shrubs often growing little more than 1-2m tall.
Most epiphytic types prefer a well drained, coarse, organic rich, media.
Propagate cultivars by cuttings.
Australia has one native species of Rhododendron. This is: R. lochae, which is an epiphytic shrub to 1m or taller with pendulant red flowers. It naturally occurs in limited areas of some Queensland rainforests.
Examples Of Other Cultivated Vireyas
R. aurigeranum -Large orange yellow flowers, aging to yellow, leathery leaves, occurs in cold high altitude New Guinea sites close to frost prone areas.
R. brookeanum -Slightly fragrant flowers, orange tinged with pink. Vigorous growth.
R. caespitosum -Dwarf epiphytic shrub only growing to 10cm wide.
R. christii -Bicoloured with red and yellow.
R. himantodes -Silvery sword-shaped leaves and small white flowers in winter.
R. jasminiflorum -Slender white trumpet flowers with pink filaments in spring, with or without scent; dark glossy green thick leaves.
R. javanicum -Large fiery orange to yellow, with pink throat, to 1.8m tall, dark green foliage, can be epiphytic in the wild.
R. konori -Small tree to 5m with leaves as large as 10cm long and 6cm wide.
R. laetum -Taller shrub or small tree to 8m high, large dark green leaves with felty underside, rich yellow flowers tinged with red or orange.
R. lineara -Small but with bright yellow flowers through spring.
R. macgregoriae -Cream-yellow, orange flowers with pink centre, vigorous but straggly growth habit.
R. polyanthemum -Highly scented bright orange flowers about 4cm long and 3-4cm across.
There are now hundreds of varieties, all based on cross-breeding species and existing varieties. Some worth noting include: 'Sweet Wendy', 'Simbu Sunset', 'Robert Withers'.