Rhododendron viscosum (Swamp azalea)

Rhododendron viscosum (L.) Torr.

Azalea serrulata Small

Azalea viscosa L.

Rhododendron coryi Shinners

Rhododendron serrulatum (Small) Millais

Rhododendron viscosum (L.) Torr. var. aemulans Rehder

Rhododendron viscosum (L.) Torr. var. glaucum (Michx.) A. Gray

Rhododendron viscosum (L.) Torr. var. montanum Rehder

Rhododendron viscosum (L.) Torr. var. nitidum (Pursh) A. Gray

Rhododendron viscosum (L.) Torr. var. serrulatum (Small) H.E. Ahles

Rhododendron viscosum (L.) Torr. var. tomentosum Rehder

Swamp azalea, swamp-honeysuckle, Clammy azalea, hammocksweet azalea, Cory azalea

Kingdom	Plantae	Plants, but not fungi, lichens, or algae
Subkingdom	Tracheobionta	Vascular plants—plants with a “circulatory system” for delivering water and nutrients
Division	Magnoliophyta	Flowering plants, also known as angiosperms
Class	Magnoliopsida	Dicotyledons—plants with two initial seed leaves
Subclass	Asteridae	A large class that encompasses asters
Order	Ericales	Tea, persimmon, blueberry, Brazil nut, azalea, many others
Family	Ericaceae	Heath or heather family
Genus	Rhododendron	From Greek rhodos, “rose,” and dendron, “tree”
Species	viscosum	From the Latin viscosus, “sticky,” in reference to the sticky substance excreted by glandular hairs on the corolla tubes of the flowers

About plant names...

Swamp azalea is native to the eastern and southern United States. It prefers swampy lowland habitats with a uniform level of soil moisture.

Plants: Woody, evergreen or deciduous shrubs are 3-5' (91-152 cm) around, rarely reaching 8' (2.4 m) and (by some accounts) up to 12' (3.7 m) in width. They have a somewhat gangly habit.

Leaves: Alternate, lustrous, dark green, narrow, obovate to oblong-obovate, with blunt or short-pointed tips. In the fall, leaves turn orange or maroon.

Flowers: White to pale pink, 1¼-1¾" (3.2-4.4 cm) long, in clusters of 4-9. Each flower consists of a long, narrow, very sticky tube, flared at the end into a corolla of five fused petal-like lobes. Five stamens extend beyond the flower, with dramatic flair. Flowers have a sweet, musky, clove-like aroma—said to be the most aromatic of all azaleas. Blooms from May to July.

Fruits: Capsules are ¼-¾" (7-20 mm) × ⅛-¼" (3-7 mm), in dark brown clusters.

Edibility: Poisonous Skull & Crossbones All parts of the plant are poisonous and may be fatal if eaten. The poison is adromedotoxin. Symptoms of poisoning include salivation, watering of eyes and nose, abdominal pain, loss of energy, depression, nausea and vomiting, diarrhea, weakness, difficulty breathing, program paralysis of extremities, and coma.

Online References:

Rhododendron viscosum at the Missouri Botanical Garden

Rhododendron viscosum on www.carolinanature.com

Rhododendron viscosum on tjhsst.edu

Rhododendron viscosum at the Lady Bird Johnson Wildflower Center

Rhododendron viscosum on plants.ces.ncsu.edu

Rhododendron viscosum on gobotany.nativeplanttrust.org

Rhododendron viscosum at Maine.gov’s Department of Conservation Maine Natural Areas Program

Rhododendron viscosum on SEINet—the Southwest Environmental Information Network

6/27/2013 · Nashua River Rail Trail, Groton Center, Groton, Massachusetts
≈ 6 × 4" (16 × 10 cm)

7/2/2016 · Nashua River Rail Trail, Groton Center, Groton, Massachusetts

12/12/2020 · By Jacquelyn Boyt

6/16/2010 · Nashua River Rail Trail, Groton Center, Groton, Massachusetts
≈ 8 × 5" (19 × 13 cm)

Rhododendron viscosum description by Thomas H. Kent, last updated 25 May 2020.

6/16/2010 · Nashua River Rail Trail, Groton Center, Groton, Massachusetts
≈ 9 × 6" (22 × 14 cm)

7/2/2016 · Nashua River Rail Trail, Groton Center, Groton, Massachusetts

6/16/2010 · Nashua River Rail Trail, Groton Center, Groton, Massachusetts
≈ 7 × 4½" (17 × 11 cm)

6/16/2010 · Nashua River Rail Trail, Groton Center, Groton, Massachusetts
≈ 5 × 3½" (13 × 9.2 cm)

6/24/2015 · Nashua River Rail Trail, Groton Ctr, Groton, Massachusetts
≈ 8 × 6" (20 × 14 cm)

6/24/2015 · Nashua River Rail Trail, Groton Ctr, Groton, Massachusetts
≈ 8 × 5" (19 × 12 cm)

6/20/2012 · Nashua River Rail Trail, Groton Center, Groton, Massachusetts
≈ 6 × 4" (15 × 10 cm)

6/16/2010 · Nashua River Rail Trail, Groton Center, Groton, Massachusetts
≈ 6 × 4" (15 × 10 cm)

6/24/2015 · Nashua River Rail Trail, Groton Ctr, Groton, Massachusetts
≈ 8 × 5" (19 × 12 cm)

Range: Zones 4-9:

About this map...