We think of rhododendrons and azaleas as being from cooler and moister climates. After all, that is where they do best. Yet, there does happen to be a native western azalea, Rhododendron occidentale, that lives in the Sierra Nevada and coastal ranges from San Diego County to just southwest of Portland, Oregon. (Azalea and Rhododendron are varied specie of the same genus.)
Bloom is mostly white, with pink, pale yellow or golden orange. Some of the fancier garden varieties bloom clear white, or with more vibrant color. The lightly fragrant, two inch wide flowers bloom in groups of two or three on open conical trusses. Each truss produces as many as a dozen flowers in sequence, so a new flower replaces a fading flower for a bit more than a week each spring.
Western azaleas plants are unfortunately not much to look at after bloom. They grow somewhat slowly and irregularly to about three to five feet tall. The two or three inch long deciduous leaves that can turn yellow and orange where autumn is cooler are more likely to turn an unimpressive grayish brown here. Foliage can fade prematurely if the weather gets too hot and arid through summer.