Alpine azalea is an alpine dwarf shrub, forming open to dense mats dotted with star-shaped pink flowers in tundra and gravelly ridges and slopes in the mountains across Denali. Plants grow only a few centimeters tall, with small (3-8 mm long) leathery, lanceolate-oblong to oblong evergreen leaves with inrolled margins. Leaves are oppositely arranged, without petioles or short-petioled. They are green above, whitish and minutely hairy beneath. Two to six star-shaped flowers grow in clusters at the end of branches, held on narrow pedicels, 1-10 mm long. The petals are fused into a bell shape, separated midway into five triangular sections, a deep to light pink color. Sepals are dark red with ciliate margins, and they remain attached to the fruit. Each flower has five stamens with dark red anthers and a single carpel. The fruit is a rounded capsule, 2-3 mm long, held upright from the pedicel, splitting into 2-3 locules. The hundred or so seeds released are winged, 0.5-1.4 mm long. No other cushion-forming alpine plant has star-shaped pink flowers and revoluteovate leaves.
L. procumbens is monoecious, with bisexual flowers. The flowers are both insect pollinated and self-fertilized—a study in northern Sweden found fruit set was reduced but still present in flowers excluded from pollinators (Kudo and Suzuki 2002). Seeds are wind-dispersed (Liu et al. 2009).
Alpine azalea is sometimes cultivated as a decorative plant in rock gardens. Tea brewed from its leaves has been used in treating tuberculosis by the Tlingit (Emmons 1991 in Garibaldi 1999).
Alpine azalea is a circumpolar species with an arctic-alpine distribution, including Eurasia, Iceland and arctic Scandinavia. In North America, alpine azalea ranges from Alaska eastward to the Atlantic Canadian provinces and Greenland, and southward into northern New York state. In the west, this species reaches Washington state. Alpine azalea is found throughout alpine and upland Alaska to the northern slopes of the Brooks Range. There are lowland localities from the Seward Peninsula along the Western coast and through the Aleutians and Bering Sea islands. In Denali, this species occurs in the alpine zone on both sides of the Alaska Range, in the Kantishna Hills and Teklanika Mountains and with a few low-elevation occurrences north of the mountains.
As the common name implies, this is an alpine species. The average site is at 991 meters in Denali, increasing in cover with elevation (to 0.55% at above 1100 m). Alpine azalea most frequently occurs on steep slopes, 20-28 degrees with a preference for south-facing slopes.