Flame Azalea

Light Needs

Partial Sun to Full Sun

(At Least 5 Hours of Direct Sunlight)

Mature Height

4-8 Feet

Mature Spread

8-10+ Feet

Growing Zones

5 to 9

Rhododendron calendulaceum, also known as Flame Azalea, is native to the southern Appalachian mountains and is one of the showiest native shrubs of North America. It is named for its large (2 - 3 inch) funnel-shaped flowers that resemble a candle flame. The flowers appear in clusters, in colors ranging from golden yellow, apricot to scarlet. The long characteristic stamens protrude from the flower and add to the spring display. The American Rhododendron Society named the flame azalea Winner of the Rhododendron Of The Year Award for the Southeast, Mid-Atlantic, North East and North West regions. 

This is an erect, loosely branched shrub that can reach 4 - 8 feet high and 8 - 10 feet wide over many years. The medium green foliage is deciduous and turns muted yellow or orange in the fall. The blooms appear in May/June and are usually not fragrant. This azalea is resistant to rabbits and attracts hummingbirds and butterflies. Flame azaleas look stunning planted en masse or as a single specimen shrub.

Flame Azalea Plant Care

As a member of the heath family, the flame azalea requires acidic soil, in a pH range of 4.5 - 6.5. The soil should also be evenly moist and well-drained. It prefers part shade and does not tolerate hot summer temperatures and direct afternoon sun. The top of the root ball should be planted slightly above the soil surface to allow its shallow roots to exchange air and drain excess moisture. Apply a weak fertilizer for acid-loving plants after flowering. All parts of this azalea are highly toxic to humans.

Prune flame azaleas after blooming in the spring. Use a pair of pruning shears to remove any dead or diseased branches. You can cut back the shrub by up to a third to control its size. Flame azaleas also benefit from clipping off spent flowers after the blooming season. 

Flame Azalea Spacing

If you are growing them in a hedge, space plants at least 6 feet apart to accommodate their spread. The growth rate for this shrub is typically slow, so the hedge may take several years to fill in. A flame azalea should not be kept in a container for more than a few years due to its large size.