Rhododendron colemanii, commonly called the Red Hills Azalea, was first described in 2008 from material collected in Monroe County, Alabama. It occurs on sandy ridges and banks of streams and on moist north-facing hardwood slopes in hardwood forests. Its range is confined to the Red Hills area of Alabama and a small area of adjacent west Georgia. Unlike most of our native deciduous azaleas, the Red Hills Azalea is a tetraploid (having twice the normal number of chromosomes or 4N). It shares this trait with Rhododendron atlanticum, Rhododendron austrinum, Rhododendron calendulaceum, and the old world Rhododendron luteum. These species make up a monophyletic group, sharing a common ancestor unique only to them.

The Red Hills Azalea is a multi-stemmed shrub reaching 20 feet in height. Leaves are deciduous, alternate, obovate to oblong in outline, with entire ciliate margins. The leaves are pubescent along the midvein on the upper surface with multicellular hairs. The lower surface is glabrous or pubescent with unicellular and scattered multicellular hairs. The midvein on the lower surface of the leaf is pubescent with appressed multicellular hairs. Flowers are produced in terminal racemes after the leaves are fully expanded. The pedicels of the flowers are densely covered with unicellular and multicellular glandular hairs. Flower color varies widely from white with a yellow blotch on the upper corolla lobe, to uniformly white, pink with yellow blotch, or uniformly pink, to rarely yellow. The outside of the flowers are covered with unicellular and multicellular gland-tipped hairs. The flowers are fragrant with a sweet, musky or lemony odor. The fruit is a cylindrical capsule with prominent raised warty bumps toward the tip, and sparsely to densely covered with unicellular and multicellular eglandular hairs, often with glandular-tipped multicellular hairs at the base. Although it is a recently described species, the Red Hills Azalea is widely available in the horticulture trade. Plants do best in a moist, organic rich, acidic soil with good drainage. Plants grow and flower best in partial sun. Too much sun can lead to leaf damage in the summer, and too much shade will cause plants to become leggy with few flowers.

Recommended for further reading:

Rhododendron colemanii: A New Species of Deciduous Azalea (Rhododendron section Pentanthera; Ericaceae) from the Coastal Plain of Alabama and Georgia, Wenyu Zhou, Taylor Gibbons, Loretta Goetsch, Benjamin Hall, Thomas Ranney, and Ron Miller, available at researchgate.net