Thin oak woodland with some evergreen cover typifies their natural habitat. Some alpine species will grow in full sun and windy positions. Extremely sensitive to salinity and high pH, rhododendrons will, however, withstand pollution. Although good cultural practices reduce the susceptibility of rhododendrons to pests and diseases, their cultivation is fraught with difficulty. Lace bugs, canker, crown rot, borer, scale and nematodes are just some of the problems.
Fungal pathogens cause flower blight and extensive defoliation.
In the US they are native to the Blue Ridge Mountains of the Carolinas and Tennessee.