Azalea is a shrub from the genus of Rhododendrons and they bloom in spring like Rhododendrons but usually a bit later. The like acid soils and shade. Unlike Rhododendrons the flowers are single rather than in clumps. There are both deciduous and evergreen Azaleas. Evergreen variety is the japanese variety which grow to about 30″ tall whereas deciduous variety can grow to almost 10′. The do love moist but well drained humus-rich soil. Plant them in shade or partial shade but not in dry shades of trees.