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Delaware Blue Azalea

Rhododendron viscosum 'Delaware Blue'

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Delaware Blue Azalea (Rhododendron viscosum 'Delaware Blue') at Glenwild Garden Center

Delaware Blue Azalea flowers

Delaware Blue Azalea flowers

(Photo courtesy of NetPS Plant Finder)

Height:  5 feet

Spread:  5 feet

Sunlight:  full sun  partial shade 

Hardiness Zone:  4a

Other Names:  Swamp Azalea, Sweet Azalea

Description:

Clusters of shell pink and white blooms blanket this very late blooming variety in late spring and sporadically in summer; an airy upright shrub that is great along borders; needs highly acidic and organic soil that is well drained

Ornamental Features

Delaware Blue Azalea is bathed in stunning clusters of lightly-scented shell pink trumpet-shaped flowers with white overtones and pink throats at the ends of the branches from late spring to early summer, which emerge from distinctive red flower buds before the leaves. It has dark green deciduous foliage. The oval leaves turn an outstanding yellow in the fall.

Landscape Attributes

Delaware Blue Azalea is an open multi-stemmed deciduous shrub with an upright spreading habit of growth. Its relatively coarse texture can be used to stand it apart from other landscape plants with finer foliage.

This is a relatively low maintenance shrub, and should only be pruned after flowering to avoid removing any of the current season's flowers. It has no significant negative characteristics.

Delaware Blue Azalea is recommended for the following landscape applications;

  • Accent
  • Mass Planting
  • General Garden Use

Planting & Growing

Delaware Blue Azalea will grow to be about 5 feet tall at maturity, with a spread of 5 feet. It tends to be a little leggy, with a typical clearance of 1 foot from the ground, and is suitable for planting under power lines. It grows at a slow rate, and under ideal conditions can be expected to live for 40 years or more.

This shrub does best in full sun to partial shade. You may want to keep it away from hot, dry locations that receive direct afternoon sun or which get reflected sunlight, such as against the south side of a white wall. It requires an evenly moist well-drained soil for optimal growth, but will die in standing water. It is very fussy about its soil conditions and must have rich, acidic soils to ensure success, and is subject to chlorosis (yellowing) of the foliage in alkaline soils. It is somewhat tolerant of urban pollution, and will benefit from being planted in a relatively sheltered location. Consider applying a thick mulch around the root zone in winter to protect it in exposed locations or colder microclimates. This is a selection of a native North American species.

 
 
Hardiness Zone Plant Height Minimum Sunlight Soil pH Preference
Characteristics
Accent  Massing  Garden 
Applications
Flowers  Fall Color  Winter Value 
Ornamental Features