• Photo of Asclepias incarnata (Asclepias incarnatas)

Plant Profile: Asclepias incarnata

Taxonomy: Asclepias incarnata

Names

Marsh Milkweed, Swamp Butterfly Weed, Swamp Milkweed

  • Photo of Asclepias incarnata (Asclepias incarnatas)

Phonetic Spelling:as-KLEE-pee-as in-kar-NAH-tuh

Genus:Asclepias

Species:incarnata

Family:Apocynaceae

Swamp Milkweed is a robust perennial herb that can reach heights of up to 5 feet. It is indigenous to the central and eastern regions of the United States, typically thriving in moist environments such as streams, ponds, and bogs. The plant produces striking pink flowers, occasionally appearing in a rose-purple hue, which bloom in mid-spring and continue to flourish until early fall. As the seed pods mature, they burst open, allowing seeds to be carried away by the wind.

This species serves as a vital food source for monarch butterfly caterpillars, while its blossoms attract a variety of pollinators. It is well-suited for use in naturalized areas, pollinator gardens, or along the banks of ponds and streams, thriving in conditions ranging from full sun to partial shade. Although it is primarily found in wet habitats, Swamp Milkweed can also adapt to drier locations, provided the soil is moderately moist, such as clay or loam.

In recognition of its beauty and ecological importance, this plant was honored as the 2005 NC Wildflower of the Year, a designation awarded by the North Carolina Botanical Garden with support from the Garden Club of North Carolina.

Asclepias incarnata Feature Summary

Asclepias incarnata Image Gallery

Tags

#fragrant
#poisonous
#white flowers
#wildlife plant
#pink flowers
#showy
#native perennial
#riparian
#wetlands
#fire
#medium flammability
#NC native
#summer flowers
#native garden
#Monarch butterfly
#pollinator plant
#native wildflower
#larval host plant
#NC Native Pollinator Plant
#butterfly friendly
#nectar plant mid-summer
#nectar plant late summer
#nectar plant early fall
#problem for cats
#pollinator garden
#problem for dogs
#problem for horses
#NC Wildflower of the Year

Similar Plants

Asclepias incarnata Feature Summary

Attributes
Central & E. Canada to W. Central & E. U.S.A.
Northeastern and southeastern United States
This plant provides nectar for pollinators including Monarch (Danaus plexippus) butterflies. It is the larval host plant for Monarch (Danaus plexippus) larvae which appear in the spring and summer and may have one to three broods in the north and four to six broods in the south. This butterfly breeds all year long in Florida, south Texas, and southeastern California. Adult Monarch butterflies feed on nectar from all species of milkweeds. Its flowers are attractive to pollinators. Deer tolerant.
Perennial
Wildlife Food Source
medium flammability
Fruit
3-4-inch long follicle seed pods split on one side to release seeds with tufts of hair that float on the wind. They are green and mature to brown.
Follicle
Brown/Copper
Cream/Tan
White
> 3 inches
1-3 inches
Flowers
Individual flowers are ¼" across, consisting of 5 white upright crowns and 5 surrounding pink to mauve petals that droop downward. Blooms in clusters called umbrels on terminal stems. Flower blooms from July to September.
Pink
White
4-5 petals/rays
< 1 inch
Leaves
Lanceolate to oblong-lanceolate green leaves are 3-6 inches long .5 to 1.5 inches wide with pointed apex and entire margins. They are either sessile or clasping.
Oblong
Lanceolate
3-6 inches
< 1 inch
Stem
Stems exude a toxic milky sap when cut.
Poisonous to Humans
Vomiting, stupor, weakness, spasms
Cardiac glycosides and resinoids
Seeds
Leaves
Stems
Flowers
Fruits
Roots
Whole Plant Traits
Perennial
Native Plant
Poisonous
Wildflower
Herb
Erect
Clumping
Cultural Conditions
Full sun (6 or more hours of direct sunlight a day)
Partial Shade (Direct sunlight only part of the day, 2-6 hours)
Acid (<6.0)
Neutral (6.0-8.0)
Good Drainage
Moist
Occasionally Wet
Coastal
Mountains
Piedmont
4a
4b
5b
5a
6a
6b
7a
7b
8b
8a
3a
3b
9a
9b
Clay
High Organic Matter
Loam (Silt)
Landscape
Butterfly Garden
Pollinator Garden
Native Garden
Border
Accent
Meadow
Slope/Bank
Pool/Hardscape
Coastal
Riparian
Pond
Near Septic
Butterflies
Pollinators
Poisonous to Humans
Problem for Cats
Problem for Dogs
Problem for Horses

Asclepias incarnata Attributes

Asclepias incarnata: Country Or Region Of Origin

Central & E. Canada to W. Central & E. U.S.A.

Asclepias incarnata: Distribution

Northeastern and southeastern United States

Asclepias incarnata: Wildlife Value

This plant provides nectar for pollinators including Monarch (Danaus plexippus) butterflies. It is the larval host plant for Monarch (Danaus plexippus) larvae which appear in the spring and summer and may have one to three broods in the north and four to six broods in the south. This butterfly breeds all year long in Florida, south Texas, and southeastern California. Adult Monarch butterflies feed on nectar from all species of milkweeds. Its flowers are attractive to pollinators. Deer tolerant.

Asclepias incarnata: Life Cycle

Annual
Biennial
Bulb
Perennial
Woody

Asclepias incarnata: Play Value

Attractive Flowers
Attracts Pollinators
Buffer
Colorful
Defines Paths
Easy to Grow
Edible fruit
Fragrance
Pieces Used in Games
Screening
Shade
Sound
Textural
Wildlife Cover/Habitat
Wildlife Food Source
Wildlife Larval Host
Wildlife Nesting
Wind Break
Wind Shimmer

Asclepias incarnata: Fire Risk Rating

extreme flammability
high flammability
low flammability
medium flammability

Asclepias incarnata Fruit

Asclepias incarnata: Fruit Description

3-4-inch long follicle seed pods split on one side to release seeds with tufts of hair that float on the wind. They are green and mature to brown.

Asclepias incarnata: Fruit Type

Achene
Aggregate
Berry
Capsule
Caryopsis
Drupe
Follicle
Legume
Nut
Pome
Samara
Schizocarp
Siliqua

Asclepias incarnata: Fruit Color

grass
Brown/Copper
grass
Cream/Tan
grass
White

Asclepias incarnata: Fruit Value To Gardener

Edible
Fragrant
Good Cut
Good Dried
Long Bloom Season
Long-lasting
Showy

Asclepias incarnata: Display/Harvest Time

Fall
Spring
Summer
Winter

Asclepias incarnata: Fruit Length

< 1 inch
1-3 inches
> 3 inches

Asclepias incarnata: Fruit Width

< 1 inch
1-3 inches
> 3 inches

Asclepias incarnata Flowers

Asclepias incarnata: Flower Description

Individual flowers are ¼" across, consisting of 5 white upright crowns and 5 surrounding pink to mauve petals that droop downward. Blooms in clusters called umbrels on terminal stems. Flower blooms from July to September.

Asclepias incarnata: Flower Color

filter_vintage
Pink
filter_vintage
White

Asclepias incarnata: Flower Inflorescence

Catkin
Corymb
Cyme
Head
Insignificant
Panicle
Raceme
Solitary
Spadix
Spike
Umbel

Asclepias incarnata: Flower Value To Gardener

Edible
Fragrant
Good Cut
Good Dried
Long Bloom Season
Long-lasting
Showy

Asclepias incarnata: Flower Bloom Time

Winter
Spring
Summer
Fall

Asclepias incarnata: Flower Petals

2-3 rays/petals
4-5 petals/rays
6 petals/rays
7 - 20 petals/rays
asymmetrical petals
Bracts
Colored Sepals
fused petals
more than 20 petals/rays
Tepals

Asclepias incarnata: Flower Shape

Bell
Cross
Crown
Cup
Dome
Funnel
Irregular
Lipped
Radial
Saucer
Star
Trumpet
Tubular
Urn
Wheel

Asclepias incarnata: Flower Size

1-3 inches
3-6 inches
< 1 inch
> 6 inches

Asclepias incarnata Leaves

Asclepias incarnata: Leaf Description

Lanceolate to oblong-lanceolate green leaves are 3-6 inches long .5 to 1.5 inches wide with pointed apex and entire margins. They are either sessile or clasping.

Asclepias incarnata: Woody Plant Leaf Characteristics

Broadleaf Evergreen
Deciduous
Needled Evergreen
Semi-evergreen

Asclepias incarnata: Leaf Color

spa
Green

Asclepias incarnata: Leaf Type

Compound (Pinnately , Bipinnately, Palmately)
Fronds
Needles
Sheath
Simple

Asclepias incarnata: Leaf Arrangement

Alternate
Opposite
Other/more complex
Rosulate
Whorled

Asclepias incarnata: Leaf Shape

Acicular
Auriculate
Cordate
Cuneate
Deltoid
Elliptical
Filiform
Lanceolate
Linear
Oblanceolate
Oblong
Obovate
Obtuse
Orbicular
Ovate
Palmasect
Palmatifid
Peltate
Pinnatifid
Pinnatisect
Reniform
Rhomboidal
Spatulate
Subcordate
Subulate

Asclepias incarnata: Leaf Margin

Crenate
Crenulate
Dentate
Denticulate
Doubly Crenate
Doubly Dentate
Doubly Serrate
Entire
Lobed
Serrate
Sinuate
Undulate

Asclepias incarnata: Hairs Present

No
Yes

Asclepias incarnata: Leaf Length

< 1 inch
1-3 inches
3-6 inches
> 6 inches

Asclepias incarnata: Leaf Feel

Fleshy
Glossy
Leathery
Papery
Prickly
Rough
Rubbery
Slippery
Smooth
Soft
Velvety
Waxy

Asclepias incarnata: Leaf Width

< 1 inch
1-3 inches
3-6 inches
> 6 inches

Asclepias incarnata Stem

Asclepias incarnata: Stem Description

Stems exude a toxic milky sap when cut.

Asclepias incarnata: Stem Color

grass
Green

Asclepias incarnata: Stem Is Aromatic

No
Yes

Asclepias incarnata: Stem Surface

Corky Ridges
Covered with a powdery bloom (glaucous)
Dull
Hairy (pubescent)
Polished
Smooth (glabrous)

Asclepias incarnata Poisonous to Humans

Asclepias incarnata: Poison Symptoms

Vomiting, stupor, weakness, spasms

Asclepias incarnata: Poison Toxic Principle

Cardiac glycosides and resinoids

Asclepias incarnata: Poison Severity

High
Low
Medium

Asclepias incarnata: Causes Contact Dermatitis

No
Yes

Asclepias incarnata: Poison Part

Bark
Flowers
Fruits
Leaves
Roots
Sap/Juice
Seeds
Stems

Asclepias incarnata Whole Plant Traits

Asclepias incarnata: Plant Type

Annual
Bulb
Carnivorous
Edible
Epiphyte
Fern
Ground Cover
Herb
Herbaceous Perennial
Houseplant
Mushroom
Native Plant
Ornamental Grasses and Sedges
Perennial
Poisonous
Rose
Shrub
Succulent
Tree
Turfgrass
Vegetable
Vine
Water Plant
Weed
Wildflower

Asclepias incarnata: Woody Plant Leaf Characteristics

Broadleaf Evergreen
Deciduous
Needled Evergreen
Semi-evergreen

Asclepias incarnata: Habit/Form

Arching
Ascending
Broad
Cascading
Climbing
Clumping
Columnar
Conical
Creeping
Dense
Erect
Horizontal
Irregular
Mounding
Multi-stemmed
Multi-trunked
Open
Oval
Prostrate
Pyramidal
Rounded
Spreading
Vase
Weeping

Asclepias incarnata: Growth Rate

Slow
Medium
Rapid

Asclepias incarnata: Maintenance

Low
Medium
High

Asclepias incarnata Cultural Conditions

Asclepias incarnata: Light

Dappled Sunlight (Shade through upper canopy all day)
Deep shade (Less than 2 hours to no direct sunlight)
Full sun (6 or more hours of direct sunlight a day)
Partial Shade (Direct sunlight only part of the day, 2-6 hours)

Asclepias incarnata: Soil pH

Acid (<6.0)
Alkaline (>8.0)
Neutral (6.0-8.0)

Asclepias incarnata: Soil Drainage

Frequent Standing Water
Good Drainage
Moist
Occasional Flooding
Occasionally Dry
Occasionally Wet
Very Dry

Asclepias incarnata: Available Space To Plant

12 inches-3 feet
12-24 feet
24-60 feet
3 feet-6 feet
6-feet-12 feet
Less than 12 inches
more than 60 feet

Asclepias incarnata: NC Region

Coastal
Mountains
Piedmont

Asclepias incarnata: USDA Plant Hardiness Zone

thermostat
3a
thermostat
3b
thermostat
4a
thermostat
4b
thermostat
5a
thermostat
5b
thermostat
6a
thermostat
6b
thermostat
7a
thermostat
7b
thermostat
8a
thermostat
8b
thermostat
9a
thermostat
9b

Asclepias incarnata: Soil Texture

Clay
High Organic Matter
Loam (Silt)
Sand
Shallow Rocky

Asclepias incarnata Landscape

Asclepias incarnata: Landscape Theme

Asian Garden
Butterfly Garden
Children's Garden
Cottage Garden
Cutting Garden
Drought Tolerant Garden
Edible Garden
English Garden
Fairy Garden
Garden for the Blind
Native Garden
Nighttime Garden
Pollinator Garden
Rain Garden
Rock Garden
Shade Garden
Water Garden
Winter Garden

Asclepias incarnata: Design Feature

Accent
Barrier
Border
Flowering Tree
Foundation Planting
Hedge
Mass Planting
Screen/Privacy
Security
Shade Tree
Small groups
Small Tree
Specimen
Street Tree
Understory Tree

Asclepias incarnata: Resistance To Challenges

Black Walnut
Compaction
Deer
Diseases
Drought
Dry Soil
Erosion
Fire
Foot Traffic
Heat
Heavy Shade
Humidity
Insect Pests
Pollution
Poor Soil
Rabbits
Salt
Slugs
Squirrels
Storm damage
Urban Conditions
Voles
Wet Soil
Wind

Asclepias incarnata: Landscape Location

Coastal
Container
Hanging Baskets
Houseplants
Lawn
Meadow
Naturalized Area
Near Septic
Patio
Pond
Pool/Hardscape
Recreational Play Area
Riparian
Rock Wall
Slope/Bank
Small Space
Vertical Spaces
Walkways
Woodland

Asclepias incarnata: Attracts

Bats
Bees
Butterflies
Frogs
Hummingbirds
Moths
Pollinators
Predatory Insects
Reptiles
Small Mammals
Songbirds
Specialized Bees

Asclepias incarnata: Problems

Allelopathic
Contact Dermatitis
Frequent Disease Problems
Frequent Insect Problems
Invasive Species
Malodorous
Messy
Poisonous to Humans
Problem for Cats
Problem for Children
Problem for Dogs
Problem for Horses
Short-lived
Spines/Thorns
Weak Wood
Weedy