Delaware Blue Azalea
Rhododendron viscosum 'Delaware Blue'
Delaware Blue Azalea flowers
(Photo courtesy of NetPS Plant Finder)
Height: 5 feet
Spread: 5 feet
Hardiness Zone: 4a
Other Names: Swamp Azalea, Sweet Azalea
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
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 foliage throughout the season. The oval leaves turn an outstanding yellow in the fall. The fruit is not ornamentally significant.
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;
- 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. 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 leaves 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.