Rhododendron arborescens (Pursh) Torr.
Smooth Azalea, Sweet Azalea
Ericaceae (Heath Family)
Synonym(s): Azalea arborescens, Rhododendron arborescens var. richardsonii
USDA Symbol: rhar3
Rhododendron arborescens is a large, loosely branched shrub, 8-12 ft. tall with an equal spread. Glossy, bright green, deciduous foliage lacks the hairs on the underside of the leaves that other native azaleas have. Foliage turns deep red to purple in fall. Fragrant, funnel-shaped, white or pink-tinged flowers with protruding, red stamens cluster in subtle groups of 3 to 6 after the leaves appear.
Relatively tall and fast-growing for a native azalea, Rhododendron arborescens is one of the hardiest native white azaleas and one of the last azaleas to bloom in the spring. It is drought-sensitive and requires moist, partially shaded sites.
From the Image Gallery
Plant CharacteristicsDuration: Perennial
Leaf: Dark Green
Size Class: 12-36 ft.
Bloom InformationBloom Color: White , Pink
Bloom Time: Jun , Jul
DistributionUSA: AL , GA , KY , MD , MS , NC , NY , PA , SC , TN , VA , WV
Native Distribution: Mountains of NY & PA to KY, s. to AL & LA
Native Habitat: Swamp forests; mt. bogs & stream banks; piedmont
Growing ConditionsWater Use: Medium
Light Requirement: Part Shade
Soil Moisture: Moist
Soil pH: Acidic (pH<6.8)
CaCO3 Tolerance: None
Soil Description: Moist, well-drained soils.
Conditions Comments: Sweet azalea is tall and fast-growing for a native azalea. It is one of the hardiest native white azaleas, and one of the last azaleas to bloom in the spring. Drought sensitive, it requires moist, partially shaded sites.
BenefitWarning: Rhododendrons contain poisonous substances and should not be ingested by humans or animals. Honey made from flowers also may be toxic. POISONOUS PARTS: All parts. Highly Toxic, May be Fatal if eaten. Symptoms include salivation, watering of eyes and nose, abdominal pain, loss of energy, depression, nausea and vomiting, diarrhea, weakness, difficult breathing, progressive paralysis of arms and legs, coma. Toxic Principle: Andromedotoxin. (Poisonous Plants of N.C.)
Conspicuous Flowers: yes
Value to Beneficial InsectsSpecial Value to Bumble Bees
This information was provided by the Pollinator Program at The Xerces Society for Invertebrate Conservation.
PropagationDescription: Combine seeds loosely with sphagnum moss and sprinkle lightly over a 2:1 perlite/peat mixture. Germinate under mist or a plastic tent. Optimum temperatures for germination are 45-50 degrees. Transplant seedlings to acid soil with a high content of orga
Seed Treatment: No pretreatment is necessary.
Commercially Avail: yes
National Wetland Indicator Status
From the National Organizations DirectoryAccording to the species list provided by Affiliate Organizations, this plant is on display at the following locations:
Delaware Nature Society - Hockessin, DE
Mt. Cuba Center - Hockessin, DE
Additional resourcesUSDA: Find Rhododendron arborescens in USDA Plants
FNA: Find Rhododendron arborescens in the Flora of North America (if available)
Google: Search Google for Rhododendron arborescens
MetadataRecord Modified: 2016-02-16
Research By: TWC Staff