Rhododendron 'Delaware Valley White'
Delaware Valley White Azalea
Cultivated azalea selection; genus native to Asia, North America, Europe
Overview
Rhododendron 'Delaware Valley White' is an evergreen azalea grown for a heavy spring display of pure white flowers, forming a dense, spreading shrub 3-4 feet (0.9-1.2 m) tall and 3-5 feet (0.9-1.5 m) wide. The single funnel-shaped flowers are 2-2.5 inches (5-6 cm) across and cover the plant in mid to late spring, with occasional faint fragrance. The evergreen leaves are 1-2 inches (2.5-5 cm) long, glossy dark green, turning bronze in cold winters. Unlike reblooming azaleas, it flowers once a year, in spring only. It grows in part shade in moist, acid, well-drained soil rich in organic matter, and is prone to root rot in wet soil, chlorosis in alkaline ground, and leaf damage in hard freezes at the cold edge of its range. All parts contain grayanotoxins that are toxic to humans and pets if eaten. Hardy in USDA zones 6-9, it is grown as a foundation shrub, low hedge, and woodland-edge plant.
Native Range
Rhododendron 'Delaware Valley White' is a cultivated azalea selection and does not occur in the wild. Its parent species belong to the genus Rhododendron spp., native to Asia, North America, and Europe, with evergreen azaleas centered in eastern Asia.Suggested Uses
Grown as a foundation shrub, a low informal hedge, a mass planting, and a woodland-edge or shade-border shrub, spaced 3-4 feet (0.9-1.2 m) apart. The white spring bloom is used to brighten shaded plantings and to pair with spring bulbs and other azaleas.How to Identify
Appearance
Size & Dimensions
Height3' - 4'
Width/Spread3' - 5'
Reaches mature size in approximately 5 years
Bloom Information
Flowering is concentrated in a single heavy flush in mid to late spring, usually April into May. The pure white flowers open together and last two to three weeks, sometimes with light fragrance. There is no repeat bloom later in the year.
Detailed Descriptions
Foliage Description
Glossy dark green, bronzing in winterGrowing Conditions
Sun Requirements
Requires 3-6 hours of direct sunlight daily
• Full Sun: 6+ hours of direct sunlight
• Partial Shade: 3-6 hours of direct sunlight
• Full Shade: Less than 3 hours of direct sunlight
Care & Maintenance
Care Guide
Grow in part shade, with shelter from hot afternoon sun and cold drying wind, in moist, acid, well-drained soil high in organic matter. Keep the shallow roots evenly moist and mulched, since the plant is sensitive to drought, but avoid wet or heavy soil that causes root rot. Alkaline soil leads to yellowing between the leaf veins. A light feeding with an acid fertilizer after flowering supports the next year's buds. Lace bugs can stipple the leaves in too much sun. Hardy in USDA zones 6-9.Pruning
Prune right after the spring flowers fade, since the buds for next year form on growth made in summer. Shape the shrub and remove dead or crossing stems at that time. It tolerates hard renewal pruning into old wood, regrowing over a season or two.Pruning Schedule
J
F
M
A
M
J
J
A
S
O
N
D
late spring
Container Growing
✓ Suitable for container growing
Minimum container size: 7 gallons