shrubN. America Native

Swamp Azalea

Rhododendron viscosum

Not currently listed at our partner nurseries.

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Essentials

At a Glance

Plant Type

Shrub

Height

60 inches

Width

60 inches

Light

Partial Sun, Shade

Zones

4, 5, 6, 7, 8, 9

Water

Medium to Wet

Humidity

Prefers high humidity

Lifespan

Long-lived deciduous shrub

Native To

Eastern North America

Toxicity

All parts are toxic if ingested

The Story

Plant Bio

Rhododendron viscosum is a deciduous azalea native to the eastern United States, typically found in wetlands, bogs, and along stream banks. It has an open, upright, and spreading habit. This species is highly valued for its intensely fragrant, clove-scented, white, trumpet-shaped flowers that bloom in late spring to early summer, after most other azaleas have finished. Its late bloom time and powerful fragrance make it a standout in the woodland garden.

Bloom Period:

EarlyLate

Uses & Benefits:

Extends the azalea blooming season into early summer with its beautiful, tubular white flowers. The main attraction is the powerful, spicy-sweet fragrance that perfumes the garden, especially in the evening. It also offers attractive fall foliage in shades of yellow, orange, and red.

Perfect for difficult, damp, shady spots in the landscape where other shrubs might fail. Its tolerance for wet feet makes it an excellent choice for rain gardens or low-lying areas.

As a native plant, it is a superb source of nectar for a wide range of pollinators, including long-tongued bees, butterflies (especially swallowtails), and hummingbirds. It is a vital part of the native ecosystem.

Marketplace

Where to Buy

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Planting

How to Grow

Select a site with dappled sunlight or morning sun and afternoon shade.
Ensure the soil is acidic, rich in organic matter, and stays consistently moist.
Dig a shallow, wide planting hole, as azaleas are shallow-rooted.
Amend the soil with compost, peat moss, or leaf mold.
Set the plant so the top of the root ball is slightly above the surrounding soil level.
Mulch with 2-3 inches of pine straw or shredded bark.

Pro Tip

Plant it where its delightful, spicy-sweet fragrance can be appreciated on summer evenings, such as near a patio, window, or garden path.

Keep It Thriving

Care Guide

Do

Provide acidic, well-drained but consistently moist soil.
Plant in a location with part shade.
Mulch annually with acidic materials like pine needles.
Water deeply during dry spells.
Allow it to develop its natural, open habit.

Don't

Don't plant in heavy, alkaline clay soil.
Avoid planting too deep; this is a common cause of failure.
Don't let the shallow root system dry out.
Avoid cultivating around the base of the plant.
Don't prune after early August, or you may remove next year's flower buds.

Seasonal Care Calendar

Task	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Fertilize
Mulch
Prune

Watch Out For

Pests & Diseases

Common Pests

Common Diseases

In the Garden

Landscape Uses & Companions

Landscape Uses

Fragrant addition to woodland gardensNaturalistic plantings near ponds or streamsKey component of a native plant border

Companion Plants

Clethra alnifolia Itea virginica Fothergilla gardenii Osmunda cinnamomea (Cinnamon Fern) Lobelia cardinalis

Multiply

Propagation Methods

Good to Know

Common Questions

Swamp Azalea questions

What zones can Swamp Azalea grow in?

Swamp Azalea is hardy in USDA Zones 4–9. Inside that range it survives winter in the ground; outside it, grow it as an annual or a container plant you protect.

Is Swamp Azalea deer resistant?

Yes — Swamp Azalea is rated deer-resistant. Deer typically pass it over, though extreme hunger can override any plant's defenses.

When does Swamp Azalea bloom?

Swamp Azalea typically blooms in early summer through mid-summer. Exact timing shifts a week or two with your zone — Sow's bloom calendar maps it to your garden.

Does Swamp Azalea need full sun?

Swamp Azalea does best in part shade.