Flame Azalea Rhododendron calendulaceum
- Phonetic Spelling
- rho-doh-DEN-dron kah-len-dew-LAY-see-um
- This plant has high severity poison characteristics.
- See below
- Description
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Rhododendron calendulaceum, commonly known as flame azalea, is an upright, loosely branched deciduous shrub that typically matures to 4-8' (infrequently to 10-15’) tall and to 8-10’ wide. It is native primarily to woodland slopes and mountain balds in the Appalachian Mountains from Pennsylvania to Georgia.
It needs a few hours of direct sun. It is a slow plant to become established. It is loosely branched plant with an upright habit. It's excellent for naturalistic landscape.
This species is an important parent of many deciduous azalea hybrids.
The common name of flame azalea is in reference to the purported resemblance of the upright flower buds to candle flames.
The bath is thin and gray-brown with a finely shredded appearance.
Fire Risk: This plant has a medium flammability rating.
Regions: Mountain
Seasons of Interest:
Blooms: Spring, summer Nut/Fruit/Seed: Late summer
Insects, Diseases, and Other Plant Problems: Rhododendrons are susceptible to insect and disease problems. Insect problems include aphids, borers, lacebugs, leafhoppers, mealybugs, mites, nematodes, scale, thrips and whitefly. Diseases include canker, crown rot, root rot, leaf spot, rust, and powdery mildew. Full sun can scorch the leaves and the roots rot if soil does not drain well. A healthy plant in the right place with proper maintenance should have few problems. This plant is frequently damaged by deer.
For suitable alternatives, see this video created by Charlotte Glen as part of the Plants, Pests, and Pathogens series.
VIDEO Created by Elizabeth Meyer for "Trees, Shrubs and Conifers" a plant identification course offered in partnership with Longwood Gardens.
- Profile Video:
- See this plant in the following landscape:
- Four-Season Garden
- Cultivars / Varieties:
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- 'Chatooga'
- 'Cherokee'
- 'Flame Azalea'
- 'Richard Beilski'
- 'Chatooga'
- 'Chatooga', 'Cherokee', 'Flame Azalea', 'Richard Beilski'
- Tags:
- Cultivars / Varieties:
-
- 'Chatooga'
- 'Cherokee'
- 'Flame Azalea'
- 'Richard Beilski'
- 'Chatooga'
- 'Chatooga', 'Cherokee', 'Flame Azalea', 'Richard Beilski'
- Tags:
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Attributes:
- Genus:
- Rhododendron
- Species:
- calendulaceum
- Family:
- Ericaceae
- Life Cycle:
- Woody
- Fire Risk Rating:
- medium flammability
- Wildlife Value:
- Hummingbirds, butterflies and other pollinators are attracted to the nectar.
- Dimensions:
- Height: 4 ft. 0 in. - 15 ft. 0 in.
- Width: 8 ft. 0 in. - 10 ft. 0 in.
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Whole Plant Traits:
- Plant Type:
- Native Plant
- Poisonous
- Shrub
- Woody Plant Leaf Characteristics:
- Deciduous
- Habit/Form:
- Erect
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Cultural Conditions:
- Light:
- Deep shade (Less than 2 hours to no direct sunlight)
- Full sun (6 or more hours of direct sunlight a day)
- Partial Shade (Direct sunlight only part of the day, 2-6 hours)
- Soil Texture:
- Loam (Silt)
- Sand
- Soil pH:
- Acid (<6.0)
- Soil Drainage:
- Good Drainage
- Moist
- Occasionally Dry
- Available Space To Plant:
- 6-feet-12 feet
- NC Region:
- Mountains
- Piedmont
- USDA Plant Hardiness Zone:
- 5b, 5a, 6b, 6a, 7b, 7a
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Fruit:
- Display/Harvest Time:
- Summer
- Fruit Type:
- Capsule
- Fruit Description:
- Displays from June to September.
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Flowers:
- Flower Color:
- Gold/Yellow
- Orange
- Pink
- Red/Burgundy
- Flower Value To Gardener:
- Showy
- Flower Bloom Time:
- Spring
- Summer
- Flower Shape:
- Funnel
- Flower Size:
- 1-3 inches
- Flower Description:
- The Flame azalea has funnel-shaped, usually non-fragrant flowers (2” diameter) that bloom in loose trusses (5-10 flowers per truss) in May-July. The flowers have exserted (protruding) showy stamens. Variable flower color ranges from yellow to orange to red.
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Leaves:
- Woody Plant Leaf Characteristics:
- Deciduous
- Leaf Color:
- Gold/Yellow
- Green
- Red/Burgundy
- Deciduous Leaf Fall Color:
- Gold/Yellow
- Red/Burgundy
- Leaf Margin:
- Entire
- Serrate
- Hairs Present:
- No
- Leaf Description:
- The leaves of the Flame azalea are medium green (1-3” long), elliptic to obovate with yellow-red fall color. They are alternate, simple with either smooth or toothed margins.
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Bark:
- Bark Color:
- Light Brown
- Light Gray
- Surface/Attachment:
- Shredding
- Bark Description:
- Thin and gray-brown with a finely shredded appearance
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Stem:
- Stem Is Aromatic:
- No
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Landscape:
- Landscape Location:
- Houseplants
- Naturalized Area
- Woodland
- Landscape Theme:
- Butterfly Garden
- Pollinator Garden
- Design Feature:
- Hedge
- Attracts:
- Bees
- Butterflies
- Hummingbirds
- Pollinators
- Small Mammals
- Specialized Bees
- Resistance To Challenges:
- Rabbits
- Problems:
- Problem for Cats
- Problem for Dogs
- Problem for Horses
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Poisonous to Humans:
- Poison Severity:
- High
- Poison Symptoms:
- Salivation, watering of eyes and nose, abdominal pain, loss of energy, depression, nausea and vomiting, diarrhea, weakness, cardiac failure, difficult breathing, progressive paralysis of arms and legs, coma.
- Poison Toxic Principle:
- Andromedotoxin, Grayantoxin
- Causes Contact Dermatitis:
- No
- Poison Part:
- Bark
- Flowers
- Fruits
- Leaves
- Roots
- Seeds
- Stems
