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Southern Indica Hybrid Azalea Rhododendron Southern Indica Hybrids

Other Common Name(s):

Phonetic Spelling
roh-do-DEN-dron
Description

Southern indica hybrid azalea is a woody, deciduous shrub in the Ericaceae (blueberry) family.  The genus name derives from the Greek words rhodo, which means rose, and dendron, meaning tree. Hybrid plants are created by cross-pollinating two varieties to achieve certain desirable plant characteristics. This group of hybrid azaleas grows well in the sun and are one of the first azaleas to bloom with very large showy blossoms that cover the shrub.

Like other azaleas, it requires humus-rich, acidic, and moist soil with good drainage. This variety of Rhododendron has numerous cultivars. Many tolerate both full sun and heat, although some may be less tolerant of high heat. This plant is moderately salt tolerant. The cultivars range in size but typically can be 6 to 12 feet high and 6 to 8 feet wide.  It is very tolerant of pruning which should be done after flowering and as the next year's flower buds form in the summer.  

Bloom colors include a wide range from bright yellow to purple, depending on the cultivar. The large blooms attract bees and hummingbirds. Plant in any sunny location as a specimen or in groups, with proper soil conditions and some dappled shade for non-high heat tolerant varieties.  They work well as background shrubs or are used as an attractive flowering hedge.

Insects, Diseases, and Other Plant Problems:  Insect problems include aphids, borers, lace bugs, leafhoppers, mealybugs, mites, nematodes, scale, thrips, and whitefly.  Diseases include canker, crown rot, root rot, leaf spot, rust, and powdery mildew. This plant is frequently damaged by deer.

While these shrubs remain very popular for landscape use, many cultivars are susceptible to Phytophthora root rot—this leads to leaf loss, reduced vigor, branch dieback, and wilting. Implement good cultural practices first, such as improving drainage with organic matter or berms and avoiding overwatering or overfertilization.  However, if you have a site with a history of this disease, consider planting one of the root rot-resistant alternative species.  

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.

More information on Rhododendron.

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See this plant in the following landscape:
Cultivars / Varieties:
  • 'Brilliant'
  • 'Formosa'
  • 'George Tabor'
  • 'G. G. Gerbing'
'Brilliant', 'Formosa', 'George Tabor', 'G. G. Gerbing'
Tags:
#hummingbirds#evergreen#hardy#showy flowers#deciduous#poisonous#full sun tolerant#heat tolerant#specimen#wildlife plant#salt tolerant#hedges#specialized bees#deer browsing plant#pollinator plant#border back#small group plantings#problem for cats#problem for dogs#bee friendly#problem for horses
 
Cultivars / Varieties:
  • 'Brilliant'
  • 'Formosa'
  • 'George Tabor'
  • 'G. G. Gerbing'
'Brilliant', 'Formosa', 'George Tabor', 'G. G. Gerbing'
Tags:
#hummingbirds#evergreen#hardy#showy flowers#deciduous#poisonous#full sun tolerant#heat tolerant#specimen#wildlife plant#salt tolerant#hedges#specialized bees#deer browsing plant#pollinator plant#border back#small group plantings#problem for cats#problem for dogs#bee friendly#problem for horses
  • Attributes:
    Genus:
    Rhododendron
    Family:
    Ericaceae
    Life Cycle:
    Woody
    Wildlife Value:
    Flowers attract humingbirds. Members of the genus Rhododendron support the following specialized bee: Andrena (Andrena) cornelli.
    Dimensions:
    Height: 6 ft. 0 in. - 12 ft. 0 in.
    Width: 6 ft. 0 in. - 8 ft. 0 in.
  • Whole Plant Traits:
    Plant Type:
    Poisonous
    Shrub
    Woody Plant Leaf Characteristics:
    Deciduous
    Habit/Form:
    Spreading
    Maintenance:
    Low
    Texture:
    Medium
  • Cultural Conditions:
    Light:
    Dappled Sunlight (Shade through upper canopy all day)
    Full sun (6 or more hours of direct sunlight a day)
    Soil Texture:
    High Organic Matter
    Loam (Silt)
    Sand
    Soil pH:
    Acid (<6.0)
    Soil Drainage:
    Good Drainage
    Moist
    Available Space To Plant:
    6-feet-12 feet
    NC Region:
    Coastal
    Mountains
    Piedmont
    USDA Plant Hardiness Zone:
    6b, 6a, 7b, 7a, 8b, 8a, 9b, 9a
  • Fruit:
    Display/Harvest Time:
    Fall
    Fruit Type:
    Capsule
  • Flowers:
    Flower Color:
    Gold/Yellow
    Pink
    Purple/Lavender
    White
    Flower Inflorescence:
    Raceme
    Flower Value To Gardener:
    Showy
    Flower Bloom Time:
    Spring
    Flower Shape:
    Funnel
    Flower Petals:
    4-5 petals/rays
    Flower Size:
    1-3 inches
    Flower Description:
    Large, single; up to 2-3 inches, of multiple colors depending on cultivar
  • Leaves:
    Woody Plant Leaf Characteristics:
    Deciduous
    Leaf Color:
    Green
    Leaf Type:
    Simple
    Leaf Arrangement:
    Alternate
    Hairs Present:
    No
  • Stem:
    Stem Is Aromatic:
    No
  • Landscape:
    Landscape Location:
    Woodland
    Landscape Theme:
    Pollinator Garden
    Shade Garden
    Design Feature:
    Border
    Hedge
    Small groups
    Specimen
    Attracts:
    Hummingbirds
    Specialized Bees
    Resistance To Challenges:
    Salt
    Problems:
    Poisonous to Humans
    Problem for Cats
    Problem for Dogs
    Problem for Horses