A deciduous azalea is a type of flowering shrub that sheds its leaves in late fall or early winter each year. Azaleas are native to regions of North America and Asia and are part of the Rhododendron genus. Most deciduous azalea varieties are North American natives, though some Asian species are also deciduous.
Azaleas are part of the Rhododendron genus and the Ericaceae family, which is a large family of shrubs that includes blueberries and cranberries as well as heather and heath. Members of the Ericaceae family share a preference for acidic soils. Azaleas are further classified into two sub genera: evergreen varieties belong to the subgenus Tsutsusi, while deciduous azaleas belong to the Pentanthera subgenus.
Deciduous azaleas drop their leaves in the fall. The evergreen cultivars retain most of their leaves year-round — they do shed some foliage, but they do it continuously and drop only a few leaves at a time. The effect is a shrub that is covered with leaves through the winter. Deciduous azaleas shed all of their leaves in late fall before cold winter temperatures set in. The shrub remains bare through the winter and regrows a new set of leaves the following spring.
There are 16 types of azaleas that are native to North America, and of these 16, all are deciduous shrubs. Most Asian azalea varieties are evergreen, though several are deciduous. North American azaleas tend to have smaller flowers than Asian varieties. To create deciduous azaleas with large flowers, Asian azaleas are often crossed with North American natives. Some of these deciduous hybrid cultivars include Yellow Cloud, Marina and Cecile.
Deciduous azalea shrubs produce blossoms in red, yellow, white, orange and purple. Some shrubs will also display blossoms with two colors. Extensive breeding has created numerous cultivars with many flower color variations. Some types of deciduous azalea shrubs display colorful fall foliage before dropping their leaves for the winter as well. The leaf colors include red or crimson as well as deep purple.
Soil preparation before planting is important to get a new deciduous azalea well established. The planting bed should be prepared with organic matter before planting. Once in the ground, azaleas benefit from a 2- to 4-inch (about a 5- to 10-cm) layer of mulch. An acidic mulch, such as pine needles or sawdust, can be used around deciduous azaleas. Once established, azaleas should be irrigated regularly to keep the soil consistently moist but never saturated.