The clammy or swamp azalea (Rhododendron viscosum (L.) Torrey) is a fragrant late-blooming azalea native to eastern North America ranging from Ontario and Maine to Florida and across the south to eastern Texas and Oklahoma. In the northern parts of its range, the swamp azalea is deciduous; in central Florida, it retains the uppermost leaves through the winter.

Although called the swamp azalea, it is seldom found in saturated soils preferring slightly elevated "hummocks" within a swamp or edge habitats where mesic (moist) forests meets the uplands. The photographed swamp azalea was growing at the edge of a remnant palmetto prairie (dry) where the land sloped down to an oxbow (old riverbed) swamp.

Like other azaleas, it sets its flowering buds in late fall blooming the following spring on "old wood", the branches of the previous year. During or shortly after flowering, the azalea begins growing new branches that bloom the next year. The usual color is white, sometimes tinged with pink, but the color can range to light red. There are yellow and pink cultivars, but white serves the swamp azalea well. In the deep shady greens of the forest, its flowers are highly visible.

The swamp azalea's flowers are tubular terminating with five recurved petals. The pedicel (stalk), the calyx (sepals), and the corolla (petals) are "densely long-stipitate-glandular", covered with stalked sticky glands that gave it the name clammy azalea. (Guide to the Vascular Plants of Florida, Richard P. Wunderlin, University of Florida Press, Gainesville, 1998)

The stamens and pistil are exserted; they extend beyond the corolla (petals). Any visiting pollinators, moths and hummingbirds, contact the stigma (pollen receptor) and the anthers (pollen bearing) while feeding on the nectar. The tacky glands may serve to discourage nectar thieves like ants that are incapable of serving as pollinators.