Know Before You Go: Information and helpful hints for your next visit
The Morton Arboretum Get tickets
Browse Trees and Plants

Swamp milkweed

Asclepias incarnata

Common names:
swamp milkweed

Content Detail

Swamp milkweed is an erect, clump-forming, native plant commonly found in wet meadows and along river bottoms. It is an essential plant for a rain garden. The rosy pink flowers are a prime source of nectar for many butterflies.

  • Family (English) Dogbane (formerly milkweed)
  • Family (botanic) Apocynaceae (formerly Asclepiadaceae)
  • Tree or plant type Perennial
  • Foliage Deciduous (seasonally loses leaves)
  • Native locale Chicago area, Illinois, North America
  • Size range Large plant (more than 24 inches)
  • Light exposure Full sun (6 hrs direct light daily)
  • Hardiness zones Zone 3, Zone 4, Zone 5 (Northern Illinois), Zone 6 (City of Chicago)
  • Soil preference Moist, well-drained soil, Wet soil
  • Tolerances clay soil, Occasional flooding, Wet sites
  • Season of interest midsummer, late summer
  • Flower color and fragrance Fragrant, Pink
  • Shape or form Upright
  • Growth rate Slow

Size and form:

Swamp milkweed grows upright 2 to 5 feet high and 2 to 3 feet wide. 

Native geographic location and habitat:

Native to northeast and southeast United States including Chicago and Illinois, it is commonly found in swampy areas and wet meadows. C-Value: 4

Attracts birds and pollinators:

The small rosy-pink flowers are a great nectar source for many butterflies and leaves are a larval host for the monarch butterfly.

Leaf or needle arrangement, size, shape, and texture:

The 3 to 6 inch long leaves are opposite, lance shaped, and with pointed tips. The monarch butterfly uses them as a larval host.

Flower description:

In summer it produces small, vanilla scented pink to mauve flowers (1/4 inch wide), with five reflexed petals in loose umbels at the stem ends.

Fruit, cone, nut, and seed descriptions:

Green seed pods (follicles) that are 4 to 5 inches long split and release light to dark brown seeds attached to silver-white silky hairs.  

Plant care:

Requires full sun in moist to wet soil, but it can tolerate well drained soils. The foliage is slow to emerge in spring. Plants have deep taproots and are difficult to transplant.

List of pests, diseases and tolerances:

Milkweed bugs and milkweed beetle are late season pests. It is resistant to deer and rabbits.

Photo Gallery (3)

Slider controls

Slider

Slider

1

Donate

Your support is vital to the Arboretum, where the power of trees makes a positive impact on people’s lives.

Make a gift