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Swamp milkweed thrives in wet habitats such as marshes, floodplains, lakes, and ponds.

Swamp milkweed thrives in wet habitats such as marshes, floodplains, lakes, and ponds. USDA, NRCS. 2012. The PLANTS Database (http://plants.usda.gov, 5 October 2012). National Plant Data Team, Greensboro, NC 27401-4901 USA.

Asclepias incarnata

Swamp milkweed

FIRST IMPRESSIONS:  This elegant plant is upright with slender willow like leaves.  In summer plants are topped by rounded pink or rose colored flower clusters which attract flocks of butterflies. Plants thrive in sunny sites with moist or saturated soils.

HABITAT & HARDINESS:  According to the USDA, Asclepias incarnata occurs in Eastern Canada and in every state in the United States except Arizona, Mississippi and states with a Pacific coastline.  

Indigenous plants are found in sunny wet areas like floodplains, river bottomland, swamps and wet meadows. 

Plants are hardy from USDA Zones 3-9.

PLANT DESCRIPTION: Asclepias incarnata is an erect clump forming perennial that grows from a taproot. 

Plants have narrow lance shaped leaves with pointed tips and smooth margins.  Stems and leaves contain a milky sap that exudes when plants are damaged.  Desirable yellow and black Monarch caterpillars feed on the foliage.

Cinnamon scented summer umbels are composed of many tiny star shaped florets.  The intricate florets look like freshly extruded pink cake decorations.  Monarch, red admiral, American lady, painted lady, swallowtail, fritillary, and hairstreak butterflies along with bumblebees, honeybees, hummingbird moths and hummingbirds seek the floral nectar. 

After flowering 4” seed pods split and release brown seed with silken parachutes that drift away on the wind.

Plants grow 3-5’ tall with 2-3’ spread.

CULTURAL & MAINTENANCE NEEDS:  Asclepias incarnata is a sun loving plant for moist or saturated soils.

It is almost impossible to grow Asclepias spp. without a throng of oleander aphids in residence.  These tiny orange plant lice suck the plant’s sugary sap and exude sticky honeydew that is the perfect cultural medium for black sooty mold.  All phases and consequences of the oleander aphid life cycle are alarming to gardeners.  The actual damage to the plant, however, is minimal and the first line of defense should be to do nothing.  If aphid damage is severely stunting growth, plants can be carefully hosed or sprayed with non-toxic soaps to remove the offenders.

Plants are not palatable to deer, rabbits and other herbivores.

LANDSCAPE USES:  Asclepias incarnata is a wise choice for a Wildlife Garden or a Wet Meadow.  Plants are also used as an Accent, Butterfly Nectar Plant, Butterfly Host Plant or as part of a Grouping or Mass Planting.  This Milkweed provides Fragrance and Showy Blooms and is often an element of Cottage Gardens, Deer Resistant Plantings, Low Maintenance Plantings, Perennial Borders, Wetlands and Wildlife Gardens.

COMPANION & UNDERSTUDY PLANTS:  Plants mingle easily with other sun & moisture lovers like Eupatorium fistulosum, Lobelia cardinalis, Helianthus angustifolius, Eupatorium colestinum and Aster novae-angliae.

Asclepias syriaca can be substituted if needed in well drained sites.

TRIVIA:  If a vertebrate animal (a bird for example) consumes a Monarch caterpillar full of milkweed toxins, the bird runs the risk of sustaining fatal damage to heart, muscles and kidneys.  The bird will usually vomit to rid itself of the poison and thereafter avoid Monarch caterpillars. 

Asclepias spp. recently belonged to their own Milkweed Family (Asclepiadaceae).  They are now classified in a subfamily of the Dogbane Family (Apocynaceae).


Height:

4-5 ft

Spread:

2-3 ft

Spacing:

3-4 ft

USDA Hardiness Zone:

3-8

Bloom Color:

Pink, Rose

Asclepias incarnata Characteristics

Exposure

  • Full Sun to Partial Shade

Critter Resistance

  • Deer Resistant

Attracts Wildlife

  • Butterflies
  • Songbirds
  • Pollinators

Soil Moisture Preference

  • Wet to Moist

Attributes

  • Naturalizing
  • Fragrant
  • Clay Soil

Flowering Months

  • June
  • July

Foliage Color

  • Green

Growth Rate

  • Fast

Salt Tolerance

  • Medium

Interesting Notes:

For more information on this plant, visit the USDA PLANTS Database:http://plants.usda.gov/java/profile?symbol=ASIN


Plants that work well with Asclepias incarnata ''

Cardinal flower Cardinal flower (Lobelia cardinalis)
Swamp sunflower Swamp sunflower (Helianthus angustifolia)
Mistflower Mistflower (Eupatorium coelestinum)
New England aster New England aster (Aster novae-angliae)
New York aster New York aster (Aster novi-belgii)
Emory's sedge Emory's sedge (Carex emoryii)
Lurid sedge Lurid sedge (Carex lurida)
Tussock sedge Tussock sedge (Carex stricta)
Scarlet rose mallow Scarlet rose mallow (Hibiscus coccineus)
Ohio spiderwort Ohio spiderwort (Tradescantia ohiensis)
Path rush Path rush (Juncus tenuis)
Soft rush Soft rush (Juncus effusus)
Spiderwort Spiderwort (Tradescantia x 'Sweet Kate')
Culver root Culver root (Veronicastrum virginicum)
Riddell's goldenrod Riddell's goldenrod (Solidago riddellii)
Lake sedge Lake sedge (Carex lacustris)
Buttonbush Buttonbush (Cephalanthus occidentalis)
Disco Belle Red Hardy Hibiscus Disco Belle Red Hardy Hibiscus (Hibiscus moscheutos 'Disco Belle Red')
Disco Belle Pink Hardy Hibiscus Disco Belle Pink Hardy Hibiscus (Hibiscus moscheutos 'Disco Belle Pink')

Substitutions for Asclepias incarnata

Swamp milkweed Swamp milkweed (Asclepias incarnata 'Ice Ballet')