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Asclepias incarnata

Image of Asclepias incarnata

Gerald L. Klingaman

Family

Asclepiadaceae

Botanical Name

Asclepias incarnata

Plant Common Name

Swamp Milkweed

General Description

Swamp milkweed is native to pond edges and stream banks of the eastern and Midwestern United States. Though this perennial is a wetland plant, it is very adaptable and at home in sunny gardens.

Delightful, lightly fragrant, purplish-pink flowers are produce summer through fall. They are born atop upright stems that hold narrow, lance-shaped leaves opposite of each other. The flowers are borne in flat clusters; each flower is complex and topped with a “crown.” The blooms are very attractive to butterflies, bees and hummingbirds. Distinctive fruits follow the bloom and are prominent, rounded, thin follicles that split down one side to reveal many seeds topped with airy plumes of silvery white hairs that catch the wind and carry the seeds away.

Swamp milkweed does produce latex when the stems are broken, but it is less milky that other species and is still high in alkaloids. Most animals find these plants unpalatable, but as the name suggests, a wide array of butterflies are attracted to butterfly weed. In fact, Monarch larvae and adults specifically rely on Asclepias for food and defense. When their young eat the foliage they become distasteful to predators.

This butterfly weed prefers a sunny location with moist to wet, average soil. It has thick, white roots adapted to growing in moist soils. It is sensitive to disturbance, so plants do not transplant well and are best propagated from seed. This adaptable and desirable perennial is great for sunny beds, wildflower or butterfly gardens. The dried pods are also used in everlasting flower arrangements making these plants equally suitable for cutting gardens.

Characteristics

  • AHS Heat Zone

    9 - 2

  • USDA Hardiness Zone

    3 - 11

  • Sunset Zone

    1a, 1b, 2a, 2b, 3a, 3b, 4, 5, 6, 7, 8, 9, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24

  • Plant Type

    Perennial

  • Sun Exposure

    Full Sun, Partial Sun

  • Height

    2'-4' / 0.6m - 1.2m

  • Width

    1'-2' / 0.3m - 0.6m

  • Bloom Time

    Early Summer, Summer, Late Summer

  • Native To

    Northeastern United States, Southeastern United States, Central United States

Growing Conditions

  • Soil pH

    Acidic, Neutral, Alkaline

  • Soil Drainage

    Poorly Drained

  • Soil type

    Clay, Loam, Sand

  • Tolerances

    Wet Site, Soil Compaction

  • Growth Rate

    Fast

  • Water Requirements

    Average Water

  • Habit

    Upright/Erect

  • Seasonal Interest

    Spring, Summer, Fall

Ornamental Features

  • Flower Interest

    Showy

  • Flower Color

    Purple, Pink

  • Fruit Color

    Green, Tan

  • Foliage Color (Spring)

    Green

  • Foliage Color (Summer)

    Green

  • Foliage Color (Fall)

    Yellow

  • Fragrant Flowers

    Yes

  • Fragrant Fruit

    No

  • Fragrant Foliage

    No

  • Bark or Stem Fragrant

    No

  • Flower Petal Number

    Single

  • Repeat Bloomer

    Yes

  • Showy Fruit

    Yes

  • Edible Fruit

    No

  • Showy Foliage

    No

  • Foliage Texture

    Coarse

  • Foliage Sheen

    Matte

  • Evergreen

    No

  • Showy Bark

    No

Special Characteristics

  • Usage

    Bog Garden, Container, Cutflower, Dried Flower/Everlasting, Mixed Border, Rock Garden / Wall, Water Gardens, Wildflower

  • Sharp or Has Thorns

    No

  • Invasive

    Sometimes

  • Attracts

    Hummingbirds, Butterflies

  • Self-Sowing

    Yes