It is a slow-growing evergreen shrub that eventually becomes 3 to 6 feet tall. In the species, the flowers are red tinged with purple, about 2 to 3 inches wide, but it has been bred in many other colors. Its leaves are bright green, about 1 inch long. R. mucronatum, the snow azalea, has Chinese ancestry but in not found in the wild. It is commonly used for ornamental pruning, grows 6 feet high and 4 to 6 feet wide.
Rhododendrons grow best in partial shade, since full sunlight tends to bleach the flowers.
They need an acid soil with a pH of 5.0 to 6.0, well mulched with organic material. Mix garden loam with equal parts of coarse sand and ground bark or oak leaves before planting. Soil around the rhododendrons' shallow roots must be kept cool and moist but well drained. All except leatherleaf rhododendron transplant well in the spring, or in the fall if mild winter weather does not damage the shallow-rooted plants. Prune rhododendrons after the flowers have faded to induce new growth.