Flame azalea
Rhododendron calendulaceum · Ericaceae
A native azalea of the Appalachian mountains, with large clusters of flowers in blazing orange, gold or scarlet in late spring, as the leaves unfold.
- Size
- 8 ft tall, 8 ft wide
- Zones
- 5 to 7
- Light
- Part sun to part shade
- Flowers
- Mid May to mid June
- Pets
- Toxic (severe)
- Job in a bed
- Anchor
A bed built around flame azalea
The planner designed this bed around flame azalea when this page was made: a 22 × 10 ft (6.7 × 3.0 m) English border in zone 6, part sun. It chose the other plants from the 708 that suit those conditions, and says below why flame azalea stands where it does.
The plants
- 1 Flame azalea × 1, orange
- 2 Bloody cranesbill 'Max Frei' × 13, pink
- 3 Creeping mahonia × 8, yellow
- 4 White mugwort × 4, cream
- 5 Brown-eyed Susan × 8, yellow
- 6 Lady's mantle × 3, green
- 7 Carpathian bellflower 'Blue Clips' × 16, blue
- 8 Sweet violet × 59, purple
- 9 Hosta 'Liberty' × 1, dark green leaves
- 10 Turk's cap lily × 6, orange
- 11 Camassia × 6, white
- 12 Easter lily × 4, white
Why this plant
- Part of the bed's structure. Shrubs and grasses keep their shape when the perennials die down. So does creeping mahonia.
Why here
- Anchors a back corner. At 8 ft it is the tallest plant here, and the tallest close the ends of the bed, where they stand in front of nothing.
- A step in the back row. Next to Turk's cap lily (6 ft): no two neighbours there are the same height, so the back steps up and down like a skyline.
- One plant, alone. A shrub is seen as an object, and needs clear ground around it.
Why now
- In flower for five weeks. From mid May to mid June.
- In company. With bloody cranesbill 'Max Frei', lady's mantle and camassia in late May: 4 kinds at once.
Planned as an English border: 15 of the 15 groups (100%) are drifts, longer along the bed than they are deep. The bed is balanced: the left half carries 52% of the visual weight and the right half 48%. The flowering is at its height in early August, with 5 kinds out together.
The planner's own design check: 10 Excellent, 6 Good, 1 Satisfactory.
Open this bed in the planner Change its size, the sun or the style, move plants about, or swap one for another.
Where flame azalea goes in a border
At 8 ft it belongs at the back of a bed. In the planner's ten height classes it is super tall (over 6½ ft).
Its job: anchor. A shrub that gives the bed permanent structure. Planted singly, as soon as the front edge is laid; everything else is arranged around it.
The colour is as hot as any flower and glows in light shade. Give it acid, leafy, well-drained soil and a cool site. The upright, open habit leaves room beneath for ferns.
- Brilliant colour at a woodland edge
- Native woodland gardens
- With mountain laurel and ferns
What to plant with flame azalea
Plants recorded as good partners for it, and what each pairing does:
- Mountain laurel: in flower together for three weeks, from late May; happy in the same moist soil.
- Christmas fern: its dark green leaves are a setting for the flowers, before and after; low enough (20 in) to stand in front of it.
- Hosta: its green leaves are a setting for the flowers, before and after; bold leaves against its medium ones; low enough (18 in) to stand in front of it.
Questions about flame azalea
Does flame azalea need sun or shade?
Flame azalea grows in part sun (4 to 6 hours of sun, including some afternoon sun) and part shade (2 to 4 hours of sun, mostly in the morning).
It wants soil that stays evenly moist, rich in organic matter, and a good soak in dry spells.
What zones does flame azalea grow in?
USDA zones 5 to 7. It is hardy to zone 5, which means it survives winter nights down to about −10 °F (−23 °C).
Above zone 7 it struggles: the zones measure winter cold, but a plant's top zone usually means the summers are too hot or the winters too mild for it to rest.
Gardening in Canada? Use the USDA zone for your town: Canada's own zone map uses different numbers.
When does flame azalea flower in my zone?
In zone 5 it flowers mid May to mid June. As a spring flower it moves about a week for every zone: earlier where it is warmer, later where it is colder.
| Zone 5 | Mid May to mid June |
|---|---|
| Zone 6 | Early May to mid June |
| Zone 7 | Early May to early June |
Worked out from Hopkins' bioclimatic law: spring arrives about four days later for each degree of latitude north, and one zone is roughly two degrees. A warm spring or a cold one moves any garden two weeks either way.
How far apart should flame azalea be planted?
6½ ft (200 cm) apart, from the middle of one plant to the middle of the next. That is a little closer than its full width of 8 ft (250 cm), so a group knits into one patch.
It grows 8 ft (250 cm) tall. Give it the full distance from anything taller, or it will lean out towards the light.
How many flame azalea plants do I need?
Usually one. At 6½ ft (200 cm) across, it is a plant you place, not one you mass. For a hedge or screen, set them 6½ ft apart: two plants for a 10 ft run.
In the bed above, the planner used one in one group.
Is flame azalea poisonous to dogs and cats?
Yes: severe toxicity to people, dogs, cats and horses. All parts, including the nectar, are highly poisonous if eaten and can affect the heart.
Rated from NC State Extension and the ASPCA. Where references disagree, the more cautious rating is used.
Is there a pet-safe plant like flame azalea?
These come closest to doing what flame azalea does, and no toxicity is recorded for them:
- Red osier dogwood: the same job in a bed, the same size and the same flowering time; white, not orange.
- Redvein enkianthus: the same job in a bed and the same flowering time; 20 in taller, 20 in narrower.
- Large fothergilla: the same job in a bed; 8 in narrower, flowers late April to mid May.
Matched the way the planner's Swap button matches plants: the same job in a bed, then size, then flowering time.
Do deer eat flame azalea?
Mostly not. NC State lists it as resistant to rabbits. No plant is proof against a hungry deer in a hard winter, but this one is low on the menu.
What flowers after flame azalea?
Flame azalea is over by mid June. These start as it finishes and carry the same spot on, so it never goes flat:
- Oakleaf hydrangea: from mid June to early August, 6½ ft tall.
- Foxglove: from early June to mid July, 4 ft tall, to stand in front of it and cover its fading stems.
- Feather reed grass 'Karl Foerster': from late June to early October, 5 ft tall, to stand in front of it and cover its fading stems.
What does flame azalea look like in winter?
Flame azalea drops its leaves and stands as bare branches. That is when to see its shape, and to prune it if it needs pruning.
Is flame azalea good for bees and butterflies?
Flame azalea is visited by pollinators, bees, specialist bees, butterflies and hummingbirds.
It is native to the United States.
More Rhododendron
- Azalea 'Delaware Valley White' Rhododendron 'Delaware Valley White'
- Azalea 'Hino-Crimson' Rhododendron 'Hino-Crimson'
- Catawba rhododendron Rhododendron catawbiense
- Evergreen azalea Rhododendron (Kurume hybrids)
- Korean rhododendron 'Cornell Pink' Rhododendron mucronulatum 'Cornell Pink'
- Northern Lights azalea Rhododendron (Northern Lights Group)
- Pinxterbloom azalea Rhododendron periclymenoides
- Reblooming azalea Rhododendron (Encore Group)
- Rhododendron 'Cunningham's White' Rhododendron 'Cunningham's White'
- Rhododendron 'Nova Zembla' Rhododendron 'Nova Zembla'
- Rhododendron 'Olga Mezitt' Rhododendron 'Olga Mezitt'
- Rhododendron 'PJM' Rhododendron 'PJM'
- Rhododendron 'Purple Gem' Rhododendron 'Purple Gem'
- Rhododendron 'Roseum Elegans' Rhododendron 'Roseum Elegans'
- Rosebay rhododendron Rhododendron maximum
- Royal azalea Rhododendron schlippenbachii
- Swamp azalea Rhododendron viscosum
- Yak rhododendron Rhododendron yakushimanum
In these guides
- Rabbit-resistant plants
- Garden plants toxic to cats
- Garden plants toxic to dogs
- Native plants for shade
- Plants for hummingbirds
- Plants for butterflies
- Plants for bees
Every fact on record
- Type
- Shrub
- Size
- 8 ft (250 cm) tall, 8 ft (250 cm) wide
- Plant
- 6½ ft (200 cm) apart
- Height class
- Super tall (over 6½ ft)
- Place in the bed
- Back
- Flowers
- Mid May to mid June; dense clusters; orange, yellow, red
- Leaves
- Medium texture, deciduous; green
- Shape
- Upright, clumping
- Hardy in
- USDA zones 5 to 7
- Light
- Part sun, part shade
- Soil
- Rich, evenly moist
- Water
- Moderate
- Feeding
- Light, in spring
- Family
- Ericaceae
- Comes from
- Eastern Appalachians, U.S.A
- Attracts
- Pollinators, bees, specialist bees, butterflies, hummingbirds
- Stands up to
- Rabbits
Checked against NC State Extension and ASPCA poison lists. Flowering times are for zone 5: later in colder zones, earlier in warmer ones. Toxicity and spread information is a general gardening guide, not veterinary or medical advice, and invasive status varies by region. If a person or pet eats a plant, contact poison control or a vet. Check your local invasive species list before planting anything with a spread warning.