Swamp Azalea (Rhododendron viscosum) August 10, 2020 2560 × 2048 Swamp Azalea (Rhododendron viscosum) Swamp Azalea or Clammy Azalea (Rhododendron viscosum). Ericaceae family. Native shrub. Acidic swamps, wetland edges. Napeague, Long Island, June 2020.