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TREES & Plants

Swamp Milkweed

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

Botanical name: 
Asclepias incarnata
All Common Names: 
Swamp milkweed
Family (English): 
Dogbane (formerly milkweed)
Family (Botanic): 
Apocynaceae (formerly Asclepiadaceae)
Tree or Plant Type: 
  • Perennial
Foliage: 
  • Deciduous (foliage falls off)
Native Locale: 
  • Chicago area
  • Illinois
  • North America
Hardiness Zones: 
  • Zone 3
  • Zone 4
  • Zone 5
  • Zone 6
Growth Rate: 
  • Slow
Light Exposure: 
  • Full sun (6 hrs direct light daily)
Tolerances: 
  • Wet sites
  • Occasional flooding
  • Clay soil
Soil Preference: 
  • Moist, well-drained soil
  • Wet soil
Flower Color & Fragrance: 
  • Fragrant
  • Pink
Size Range: 
  • Large plant (more than 24 inches)
Shape or Form: 
  • Upright
Landscape Uses: 
  • Massing
  • Foundation
  • Mixed border
Time of Year: 
  • Mid summer
  • Late summer
More Information: 

Size

2 to 5 feet high and 2 to 3 feet wide

Tree & Plant Care

Foliage is slow to emerge in spring.
Easily grown in medium to wet soils in full sun.
Plants have deep taproots and difficult to transplant.

Disease, pests and problems

Milkweed bugs and milkweed beetle are late season pests.

Native geographic location and habitat

C-Value: 4
Commonly found in swampy areas and wet meadows.

Attracts birds & butterflies

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

Leaf or needle arrangement, size, shape, and texture

Leaves are opposite,  2 to 6 inches long, lance shaped with pointed tips

Flower arrangement, shape, and size

Small, fragrant, pink to mauve flowers (1/4 inch wide),  with five reflexed petals in a tight clusters (umbels) at the stem ends in summer.

Fruit, cone, nut, and seed descriptions

 Long (4  to 5 inches) green seed pods (follicles) split and release light to dark brown seeds attached to silver-white silky hairs.