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Cressler, Alan
Rhododendron arborescens
Rhododendron arborescens (Pursh) Torr.
Smooth Azalea, Sweet Azalea
Ericaceae (Heath Family)
Synonym(s): Azalea arborescens, Rhododendron arborescens var. richardsonii
USDA Symbol: rhar3
USDA Native Status: L48 (N)
Rhododendron arborescens is a large, loosely branched shrub, usually 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.
Plant Characteristics
Duration: PerennialHabit: Shrub
Leaf Retention: Deciduous
Leaf Arrangement: Alternate
Leaf Complexity: Simple
Breeding System: Flowers Bisexual
Fruit Type: Capsule
Size Notes: Up to about 20 feet tall, often shorter.
Leaf: Dark Green
Bloom Information
Bloom Color: White , PinkBloom Time: May , Jun , Jul , Aug
Distribution
USA: AL , GA , KY , MD , MS , NC , NY , PA , SC , TN , VA , WVNative Distribution: Mountains of NY & PA to KY, s. to AL & LA
Native Habitat: Swamp forests; mt. bogs & stream banks; piedmont
Growing Conditions
Water Use: MediumLight 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.
Benefit
Warning: 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 Insects
Special Value to Bumble BeesThis information was provided by the Pollinator Program at The Xerces Society for Invertebrate Conservation.
Propagation
Description: 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 orgaSeed Treatment: No pretreatment is necessary.
Commercially Avail: yes
National Wetland Indicator Status
| Region: | AGCP | AK | AW | CB | EMP | GP | HI | MW | NCNE | WMVE |
| Status: | FACW | FAC | FAC |
From the National Organizations Directory
According 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
Web Reference
Webref 38 - Flora of North America (2019) Missouri Botanical Garden, St. Louis, MO & Harvard University Herbaria, Cambridge, MA.Webref 23 - Southwest Environmental Information Network (2009) SEINet - Arizona Chapter
Additional resources
USDA: Find Rhododendron arborescens in USDA PlantsFNA: Find Rhododendron arborescens in the Flora of North America (if available)
Google: Search Google for Rhododendron arborescens
Metadata
Record Modified: 2023-04-03Research By: TWC Staff