Also known as clammy azalea, and swamp honeysuckle, this flowering deciduous shrub is native to the wetlands of eastern and southern US and a member of the heath family, Ericaceae, that also includes heather, mountain laurel, and blueberry. The plant grows up to ‘8 tall and spreads with maturity. The leathery, oval leaves are up to 2.5″ long and are clustered at the branch tips. The leaves are dark green before turning yellow, orange and purple in fall. Terminal clusters of 4-9 clove-scented, white to pink flowers appear after the leaves emerge from late spring into summer. With 4-5 petal-like lobes, each flower is 1.25″ across, tubular, and very sticky. The flowers are attractive to hummingbirds, bees, butterflies and other pollinators and are good in the vase. Swamp azalea is the last of the azaleas to bloom and tolerates heat as well as wet soil. It is a good choice for native plant, fragrance, pollinator, hummingbird, butterfly, woodland, shade and water gardens. It is especially nice near a patio where the fragrance can be enjoyed. The genus name, Rhododendron, comes from the Greek words ῥόδον (rhódon) meaning rose, and δένδρον (dendron), meaning tree. The specific epithet, viscosum, is the Latin word meaning sticky and refers to the condition of the corolla.
Type: Flowering deciduous shrub
Outstanding Features: Fragrant flowers; fall coloration
Form: Rounded, spreading
Growth Rate: Slow
Bloom: Clusters of white to pink tubular flowers in late spring to summer
Size: 2-8′ H x 2-8′ W
Light: Dappled or part shade
Soil: Average, acidic, moist to wet, but well-drained enough that the roots are not submerged for extended amounts of time.
Hardiness: Zones 4-9
Care: Plant away from black walnut and butternut tree both of which secret substances that inhibit the growth of azaleas. Protect from wind and mulch to keep the roots cool, moist, and protected from cold in winter.
Pests and Diseases: Phytophthora root rot, crown rot, leaf spot, canker, powdery mildew, rust, aphids, mealybugs, mites, scale, thrips, borers, whitefly, leafhoppers, lacebugs.
Propagation: Root cuttings, layering, seed
Outstanding Selections:
‘Lemon Drop’
‘Pink Mist’
‘Pink Rocket’
‘Viscosum’
Photo Credit: Wikipedia