Why are azaleas included in the genus Rhododendron?

Azaleas are included in the genus Rhododendron because they are taxonomically classified as specific species within that diverse group of woody flowering plants in the heath family (Ericaceae). While azaleas were formerly placed in their own separate genus, Azalea, they are now recognized as members of the genus Rhododendron.12

Although they share the same genus, azaleas are distinguished from other rhododendrons by certain physical characteristics. Azaleas are typically deciduous, whereas many other rhododendrons are evergreen. Additionally, azalea flowers are often funnel-shaped with five projecting stamens, while other rhododendron flowers are more frequently bell-shaped and possess ten or more stamens. Despite these differences, intermediate forms exist, reinforcing their shared classification within the same genus.12