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Flame Azalea
Azalea calendulacea
Medium · Some experienceAbout Flame Azalea
Flame Azalea is the most spectacular native deciduous azalea of the Appalachian Mountains, producing blazing clusters of flowers in shades of yellow, orange, gold, and fiery red before the leaves fully emerge. Growing 4-10 feet tall at elevations up to 6,000 feet, it creates breathtaking displays along the Blue Ridge Parkway and Appalachian Trail in May and June. William Bartram, encountering it in 1773, called it 'the most gay and brilliant flowering shrub yet known.'
- Cold-hardy
- Native
- Pollinator-friendly
How to care for Flame Azalea
Watering
- Springevery 5 days
- Summerevery 3 days
- Fallevery 7 days
- Winterevery 14 days
Soil · Acidic · pH 4.5–6
- Top dressingPine needle mulch10%
- Main mixAcid-lover mix + peat 3:175%
- DrainageGravel15%
Never add lime or wood ash — it cancels out the acidity.
FERTILIZER
Acid-Loving Feed 4-3-4
One bag does both jobs. An acid feed carries the usual nitrogen, phosphorus and potassium, plus the sulfur and iron that keep the soil sour enough for the roots to take them up at all.
- Nitrogen · Leaves
- Phosphorus · Roots + Blooms
- Potassium · Strength
- Springevery 30 days
At a Glance
- NativeNorth America
- Height4–10 ft (1.2–3 m)
- Spread4–8 ft (1.2–2.4 m)
- Flower colorOrange, Yellow, Red, Coral
- Foliage colorGreen, Bronze, Red, Purple
- SoilLoamy, Well-drained, Acidic
- LocationsYard
Bloom time
BLOOM CYCLE
Peak bloom
May–Jun
Fiery orange-yellow-red clusters May to June
Fragrance
NO FRAGRANCE
Essentially unscented, unlike R. arborescens and R. viscosum.
Toxicity
Humans Toxic · Pets Toxic
grayanotoxins
Toxic
- Leaf
- Flower
- Ingestion
EXPOSURE Eating leaves and flowers.
EFFECT Nausea, vomiting, cardiac effects from grayanotoxins.
NOTE Documented concern for humans: Nausea, vomiting, cardiac effects from grayanotoxins.
Toxic
- Leaf
- Flower
- Ingestion
EXPOSURE Eating leaves and flowers.
EFFECT Vomiting, diarrhea, weakness, cardiac arrhythmia.
NOTE ASPCA toxic. All Rhododendron/Azalea severely toxic.
Toxic
- Leaf
- Flower
- Ingestion
EXPOSURE Eating leaves and flowers.
EFFECT Vomiting, diarrhea, weakness, cardiac arrhythmia.
NOTE ASPCA toxic. All Rhododendron/Azalea severely toxic.
Educational information, not medical or veterinary advice. If exposure is suspected, contact a doctor or veterinarian.
DISTRIBUTION
- Native
- North America
History
Rhododendron calendulaceum (originally published by Michaux as Azalea calendulacea in 1803) occurs naturally along the Appalachian mountains from southern Pennsylvania to northern Georgia, most abundantly in the southern Appalachians from West Virginia to north Georgia, on dry ridges, rocky slopes, and balds. The epithet calendulaceum means resembling Calendula (marigold), referring to the glowing orange to yellow flower color—the most vividly colored of any eastern native azalea. Naturalist William Bartram, visiting the Nantahala Mountains in 1776, wrote one of the most famous passages in American natural history: 'This epithet fiery I annex to this most celebrated species of Azalea, as being expressive of the appearance of its flowers, which are in general of the color of the finest red lead, orange, and bright gold...
the hills are set on fire with them.' In peak bloom along the Blue Ridge Parkway and Roan Mountain (late May to early July depending on elevation) wild colonies still produce the spectacle Bartram described.
Color varies naturally from pale yellow through apricot, orange, salmon, scarlet, and red. William Bartram's ecstatic 1773 description of flame azalea hillsides in the Carolina mountains became one of the most famous passages in American botanical literature. Roan Mountain on the Tennessee-North Carolina border hosts some of the most spectacular wild displays, drawing thousands of hikers each June.
Symbolism & meaning
What It Symbolizes
The Flame Azalea ignites the Appalachian highlands each spring with passionate oranges and reds, and so it can symbolize passion in its most untamed form. Another layer is freedom, the wild beauty of a shrub that needs no gardener to set the mountain slopes alight. To meet a flame azalea blooming on a ridge is to understand why the southern mountains have always been spoken of as a country of fire as well as mist.
- Passion — fiery colors that ignite mountain slopes
- Freedom — wild beauty of the Appalachian highlands
Where the Name Comes From
'Calendulacea' means 'marigold-like', referring to the warm orange-yellow flower colors reminiscent of calendula.
Uses & Fun Facts
- Flame-orange blooms attract swallowtails and hummingbirds
- Native Flame Azalea showpiece for woodland gardens
Related plants
More Azalea plants
Plants with similar care
Japanese MapleAcer palmatum
Azure MonkshoodAconitum carmichaelii
Florida HobblebushAgarista populifolia
Shell GingerAlpinia zerumbet
Frequently asked questions
How often should I water Flame Azalea?
In summer, water about every 3 days; in winter, about every 14 days. Adjust for heat, pot size and drainage.
How much light does Flame Azalea need?
Part shade: 2–4 hrs direct. Watch the leaves — scorching or stretching means the light needs adjusting.
Is Flame Azalea toxic to cats or dogs?
Pets Toxic (Dogs Toxic · Cats Toxic) Educational information, not medical or veterinary advice. If exposure is suspected, contact a doctor or veterinarian.
Is Flame Azalea easy to grow?
It is moderately demanding: a good choice once you have a little experience.
When does Flame Azalea bloom?
It typically blooms May–Jun in the Northern Hemisphere.
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