Swamp Azalea

Rhododendron viscosum

Other names: Clammy Azalea, Honeysuckle Azalea

Plant Details

USDA Plant Hardiness Zones: 4a-9b Find Your Zone

Plant Type: Deciduous Flowering Shrub

Height at Maturity: 3-5′, but sometimes is seen up to 8′

Width at Maturity: 3-5′

Spacing: 3-4′ for solid hedges; 8’+ for space between plants

Flower Color: White to Soft Pink

Flower Size: 1.5-2″

Flowering Period: Late Spring to Early Summer

Flower Type: Single, Trumpet-shape

Fragrant Flowers: Yes! Strong musky clove fragrance

Foliage Color: Dark Green

Fragrant Foliage: No

Berries: No

Berry Color: NA

Sun Needs: Part to Mostly Shade, Dappled Shade, Morning Sun with Afternoon Shade, All Day Filtered Sun

Water Needs: Average

Soil Type: Clay (amend heavy clay), Loam, Sandy (amend quick draining soil to retain moisture), Silt

Soil Moisture / Drainage: Consistently Moist But Well Drained to Wet, but not in submerged or standing in water

Soil pH: 4.5 – 6.5 (Acid to Slightly Acid)

Maintenance / Care: Low

Attracts: Butterflies, Beneficial Pollinators, Hummingbirds, Visual Attention

Resistances: Cold Temperatures (-30F / Zone 4a-9b), Heat (Zone 9b), Humidity, Shade, Rabbits, Wet Soil

Description

An azalea that will grow in wet soil…surely not? Well, meet the Rhododendron viscosum, commonly known as Swamp Azalea, a North American native deciduous Rhododendron adored for its showy and wonderfully fragrant flowers, and its ability to thrive in moist to wet soils. In its native habitat it thrives in swamps, bogs, stream margins and wet lowlands from southwestern Maine to northeastern Ohio south to Florida and Alabama, and can even be found at higher elevations in the Appalachian Mountains. One of the last azaleas to flower in the season (May to July), it features abundant clusters of very fragrant white to soft pink honeysuckle-like flowers with a clove-like aroma that are great for cut flowers. Each flower has 5 petal-like lobes and long stamens. It typically grows 3 to 5 feet tall and wide, however is sometimes seen at up to 8 feet. Branching opens up with age. Narrow, oval-shaped, dark green leaves through the warm season turn attractive shades of yellow, orange and purple with the arrival of cooler temperatures in fall. Extremely cold and heat hardy from USDA Zones 4a to 9b.

Landscape & Garden Uses

Growing 3 to 5 feet tall and equally as wide, the Swamp Azalea is ideal for use as a specimen, in groupings, or as a natural hedge in partially shaded landscape, woodland and mixed flowering borders. It also grows well in containers that can be situated on patios and around other outdoor living spaces where the pretty flowers and fragrance can be enjoyed from close up. Plants in groups with earlier blooming azaleas to extend the annual azalea bloom period. Plants thrive when sited in moist soils near stationary or moving water. A fine selection for fragrance gardens, cut flower gardens, Azalea gardens, woodland gardens, white theme gardens, and cottage gardens.

Suggested Spacing: 3 feet apart for hedge or grouping; 8 feet or more for space between plants

Growing Preferences

The Swamp Azalea is easy to grow in an acidic, consistently moist to wet soil, though it won’t tolerate being submerged under water. Morning and evening sun are okay but it prefers shade or well-filtered sun during the afternoon hours. Prefers a sun dappled shade or high open part shade. In average well-draining garden soil, this azalea likes to be mulched with wood or straw mulch to help prevent the soil from completely drying out. Native azaleas are very low-maintenance, requiring little if any pruning. That said, occasionally we might prune a stray branch that is spoiling the natural form of the plant and snip off spent flower stems immediately after the bloom to encourage a fuller plant, but that’s up to you.

Helpful Articles

Click on the link below to find helpful advice from our experts on how to plant, prune, fertilize and water native azaleas.

How To Plant & Care For Native Azaleas

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