Lady Bird Johnson Wildflower Center - The University of Texas at Austin information

 Native Plant Database

Asclepias incarnata

Swamp milkweed, Pink Milkweed

Asclepiadaceae (Milkweed Family)

Asclepias incarnata (Swamp milkweed)
Marcus, Joseph A.
The large, bright, terminal blossoms of this showy, 2-4 ft. perennial are made up of small, rose-purple flowers. Deep pink flowers clustered at the top of a tall, branching stem, bearing numerous narrow, lanceolate leaves. Opposite, narrow, lance-shaped leaves line the erect, open-branched stem. Elongated, tan-brown seed pods persist into winter.

The juice of this wetland milkweed is less milky than that of other species. The genus was named in honor of Aesculapius, Greek god of medicine, undoubtedly because some species have long been used to treat a variety of ailments. The Latin species name means flesh-colored.

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Plant Characteristics

Duration: Perennial
Habit: Herb
Leaf Arrangement: Opposite
Leaf Complexity: Simple
Leaf Shape: Lanceolate
Leaf Venation: Pinnate
Leaf Pubescence: Glabrous
Leaf Margin: Entire
Leaf Apex: Acute
Leaf Base: Rounded
Breeding System: Flowers Bisexual
Fruit Type: Follicle
Size Notes: 2-5 ft (60-152 cm).
Leaf: Leaves: Long and narrow and taper off to a point, 2 3/4 6 in (7-15 cm) long and 1/2 1 in (1- 2 cm) wide. Glabrous. Leaf texture is coarse, color is green, and plant stands erect. The leaves on plants exposed to full sun are often purplish toward the end of the growing season. Leaf arrangement is opposite and attachment is petiolate.
Flower: Color is generally light pink to light purple but seeds of a reddish form known as pulchra are sold for gardens. Similarly, white variants are found in the wild and are sold by nurseries. 20+/- flowers per umbel.
Fruit: Pods erect, long 4 in (10 cm) and narrow like the leaves. The pods are often in pairs. Seed Color is brown, 5/16 in (8 mm) long.
Size Class: 3-6 ft.

Bloom Information

Bloom Color: Pink , Purple
Bloom Time: Jun , Jul , Aug , Sep , Oct


USA: AL , AR , CO , CT , DE , FL , GA , ID , IL , IN , IA , KS , KY , LA , ME , MD , MA , MI , MN , MO , MT , NE , NV , NH , NJ , NM , NY , NC , ND , OH , OK , PA , RI , SC , SD , TN , TX , UT , VT , VA , WV , WI , WY , DC
Canada: MB , NB , NS , ON , PE , QC
Native Distribution: Manitoba, Quebec, and Nova Scotia; from New England south to Georgia; west to Louisiana, and Texas; north to North Dakota.
Native Habitat: Wet Meadow, Prairie, Field, Riparian, Swamp, Marsh. Most often found on the margins of flooded plains, lakes, ponds, waterways, marshes, swamps, and other wet areas.

Growing Conditions

Water Use: High
Light Requirement: Sun , Part Shade
Soil Moisture: Wet , Moist
CaCO3 Tolerance: Medium
Soil Description: Rich, wet, very muddy to average garden moisture. One of the few ornamentals that thrives in mucky clay soils. Prefers neutral to slightly acidic soil but will tolerate heavy clay.
Conditions Comments: With its showy flower clusters that attract butterflies and hummingbirds, swamp milkweed is underutilized in gardens. In moist soils or in a pond, it will thrive. The interesting seed pods look like other milkweeds. Swamp milkweed will inevitably have aphids. The insects are not a problem unless the plant looks sick; at that point an effective treatment is to spray the plant and aphids with soapy water. Another possible treatment is to support the plant part with your hand and blast it with high-pressure water. Good for wetland gardens and habitat.


Use Ornamental: Herbaceous perennial forming stately clump of upright stems with long narrow leaves and heads of fragrant soft mauve pink flowers, composed of many small intricate flowers.
Use Wildlife: Milkweeds are an important food source for the monarch caterpillar.
Use Food: Although milkweeds are poisonous raw, the young shoots, leaves and seed pods are all edible cooked. When placed in cold water, brought to a boil and simmered till tender, milkweeds are said to be delicately flavoured and harmless. (Poisonous Plants of N.C. State) The flower buds, nectar-sweet flowers and seeds are also edible. (Kershaw)
Use Medicinal: In the past, the roots of swamp milkweed were simmered to make a tea taken in small quantities both as a general purge and to destroy and expel parasitic worms.
Warning: All parts. Toxic only in large quantities. Syptoms include, vomiting, stupor, weakness, spasms. Toxic Principle: Cardiac glycosides and resinoids.
Conspicuous Flowers: yes
Fragrant Flowers: yes
Interesting Foliage: yes
Attracts: Hummingbirds , Butterflies
Larval Host: Monarch and Queen butterflies.
Nectar Source: yes
Deer Resistant: High
Poisonous: yes

Butterflies and Moths of North America (BAMONA)

Asclepias incarnata is a larval host and/or nectar source for:
(Danaus plexippus)

Larval Host
Learn more at BAMONA
(Danaus gilippus)

Larval Host
Learn more at BAMONA

Last Update: 2014-10-11