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Asclepias incarnata - Swamp Milkweed (photo credit: Flying H Photography)


Asclepias incarnata

Milkweed, Swamp

Asclepias incarnata, or swamp milkweed, is an erect, clump-forming, Missouri native plant which is commonly found in swamps, river bottomlands and wet meadows. It typically grows 3-4' tall on branching stems. Small, fragrant, pink to mauve flowers appear in tight clusters at the stem ends in summer. Stems exude a toxic milky sap when cut. Flowers are followed by attractive seed pods which split open when ripe releasing silky-haired seeds easily carried by the wind. Flowers are very attractive to butterflies as a nectar source. In addition, swamp milkweed is an important food source for the larval stage of Monarch butterflies!


Asclepias incarnata is a Missouri native on the MSD Stormwater BMP Native plant list and used in Wet Pond and Wetland applications. Treated only when necessary with non-systemic, biological insecticides as to not cause harm to the Monarch larvae.

Host plant for the following butterflies (nectar)-- American Copper, American Lady, Baltimore Checkerspot, Banded Hairstreak, Black Swallowtail, Bronze Copper, Cabbage White, Common Buckeye, Delaware Skipper, Eastern Tailed-Blue, Eastern Tiger Swallowtail, Fiery Skipper, Giant Swallowtail, Gray Hairstreak , Great Spangled Fritillary, Hoary Edge, Little Glassywing, Lorquin Admiral, Monarch (exclusive food source for the caterpillar), Mourning Cloak, Orange Sulphur, Painted Lady, Pearl Crescent, Peck's Skipper, Pipevine Swallowtail, Queen, Question Mark, Red Admiral, Red-banded Hairstreak, Red-spotted Purple, Sachem, Silver-spotted Skipper, Silvery Checkerspot, Sleepy Orange, Southern Cloudywing, Spicebush Swallowtail, Spring Azure, Two-tailed Swallowtail , Variegated Fritillary, Viceroy, Zabulon, Zebra Longwing, Zebra Swallowtail

Host plant for the Monarch caterpillar (food source) as well as 11 other butterflies and moths!

Milkweed, Swamp Growing and Maintenance Tips:

Easily grown in medium to wet soils in full sun. Surprisingly tolerant of average well-drained soils in cultivation even though the species is native to swamps and wet meadows. Plants have deep taproots and are best left undisturbed once established. Foliage is slow to emerge in spring.


36-48 in



24-36 in


Hardiness Zone:

3 - 6

Characteristics & Attributes for Asclepias incarnata

Soil Moisture Preference
Attracts Wildlife
Critter Resistance
Deer Resistant
Season of Interest (Flowering)
Border or Bed
Focal Point
Mass Planting
Clay Soil
Great Companion Plants for Asclepias incarnata
Cardinal Flower Cardinal Flower (Lobelia cardinalis )
Ornamental Onion Ornamental Onion (Allium tanguticum 'Summer Beauty')
Bee Balm Bee Balm (Monarda didyma 'Balmy Purple')
Lily turf, creeping Lily turf, creeping (Liriope spicata )
Blazing Star Blazing Star (Liatris ligulistylis )
Creeping Jenny Creeping Jenny (Lysimachia nummelaria 'Goldi')
Blue Cardinal Flower Blue Cardinal Flower (Lobelia siphilitica )
Siberian Iris Siberian Iris (Iris sibirica 'Caesar's Brother')
Similar Plants to Asclepias incarnata
Butterfly Weed Butterfly Weed (Asclepias tuberosa )
Swamp Milkweed Swamp Milkweed (Asclepias incarnata 'Ice Ballet')
Butterfly Weed Butterfly Weed (Asclepias tuberosa 'Hello Yellow')
Swamp Milkweed Swamp Milkweed (Asclepias incarnata 'Cinderella')