Introduction

Florida flame azalea is well-noted for its vivid display of yellow-orange, slightly fragrant, clustered blooms appearing in spring before the new leaves emerge. Well-suited to mass plantings in natural woodland settings, Florida flame azalea makes a traffic-stopping showing whenever it is in full bloom. It is usually quite a surprise in flower since it generally goes unnoticed during the rest of the year.

General Information

Scientific name: Rhododendron austrinum

Pronunciation: roe-duh-DEN-drun oss-TRY-num

Common name(s): Florida flame azalea

Family: Ericaceae

Plant type: shrub

USDA hardiness zones: 6B through 9 (Fig. 1)

Planting month for zone 7: year round

Planting month for zone 8: year round

Planting month for zone 9: year round

Origin: native to Florida

Uses: mass planting; specimen; container or above-ground planter; trained as a standard; attracts hummingbirds

Availability: somewhat available, may have to go out of the region to find the plant

Description

Height: 6 to 10 feet

Spread: 4 to 8 feet

Plant habit: vase shape; upright

Plant density: moderate

Growth rate: slow

Texture: fine

Foliage

Leaf arrangement: alternate

Leaf type: simple

Leaf margin: entire

Leaf shape: ovate

Leaf venation: pinnate

Leaf type and persistence: deciduous

Leaf blade length: 2 to 4 inches

Leaf color: green

Fall color: yellow

Fall characteristic: not showy

Flower

Flower color: yellow-orange

Flower characteristic: pleasant fragrance; spring flowering

Fruit

Fruit shape: elongated

Fruit length: .5 to 1 inch

Fruit cover: dry or hard

Fruit color: brown

Fruit characteristic: inconspicuous and not showy

Trunk and Branches

Trunk/bark/branches: not particularly showy; typically multi-trunked or clumping stems

Current year stem/twig color: brown

Current year stem/twig thickness: thick

Culture

Light requirement: plant grows in part shade/part sun

Soil tolerances: clay; acidic; loam; sand

Drought tolerance: moderate

Soil salt tolerances: poor

Plant spacing: 36 to 60 inches

Other

Roots: usually not a problem

Winter interest: no special winter interest

Outstanding plant: plant has outstanding ornamental features and could be planted more

Invasive potential: not known to be invasive

Pest resistance: long-term health usually not affected by pests

Use and Management

Florida flame azaleas are rather straggly and upright when very young but will spread out, the large, medium green leaves causing the branches to gently cascade down to the ground. A single specimen should be allowed at least six feet of spread to develop into the cascading form. These make a dramatic effect planted in mass three to five feet apart as part of a shrub border.

Rich, moist, acidic soil in light shade with some direct sun, protected from harsh winds, is an ideal location for Florida flame azaleas. Azaleas grow best in filtered shade from tall trees, but will bloom poorly when in root competition with trees. Plants are very sensitive to drought. The soil must be open and porous, yet able to retain water well. A thick mulch is recommended to help ensure adequate moisture retention and root growth. Locate the plants so that they can receive frequent irrigation. Roots are located in the top several inches, even in sandy, well-drained soil.

Pruning is seldom necessary except to control shoots that extend above the normally mounded shape. Since plants bloom on the previous year's growth, any desired pruning should be done in spring after flowering. Pinching new shoots when they are several inches long increases branching and flower display.

The cultivar 'My Mary' has 2.5-inch-wide, single, fragrant yellow flowers.

Propagation is by seed sown in late fall on moist peat moss or by softwood cuttings taken in late spring.

Pests and Diseases

Mites.

Problems include iron deficiencies from too high a soil pH and mushroom root rot from over watering or poorly drained soil.