The azalea is a flowering shrub related to the rhododendron. According to the Azalea Society of America, the azalea thrives in variable shade. This type of shade is provided by trees that sway or blow in the wind, offering sun one moment and shade the next to azaleas.
The azalea prefers filtered light or partial shade. With too much shade, the plant does not flower. In full sun, the shrub is compact and the blooms, though prolific, do not last long.
An azalea native to the United States is deciduous and sheds leaves over winter months, while an azalea native to European areas is evergreen with leaves all year.
Azaleas, hybridized for hundreds of years, offer varieties for most climate zones. Some are more shade or more sun tolerant depending on the cultivar.
The University of California recommends evergreen azaleas based on Indica or Indian hybrids. These hybrids grow in full sun and are nicknamed sun azaleas.
The University of Illinois recommends azaleas such as the Flame Azalea that tolerates partial to full shade. Other hybrids are based on this azalea.