Asclepias syriaca

Asclepias syriaca, (Common Milkweed)

General Description

The common milkweed, A. syriaca, is the plant that most people associate with the word “milkweed”.  This is a tall and conspicuous species that sometimes forms large clones. The umbels bear large balls of pink to purplish flowers that have an attractive odor. This species is known to form hybrids with both A. exaltata (in the east) and A. speciosa (in the west).  The seed pods open in the fall and early winter dispensing wind borne seeds. Among the milkweeds, this species is the best at colonizing in disturbed sites. Within its range it can be found in a broad array of habitats from croplands, to pastures, roadsides, ditches and old fields. It is surprisingly rare in prairies in the Midwest being found mostly in disturbed sites within these habitats. As an indigenous species of the southern Great Plains, it has all the attributes of what some ecologists call a “fugitive species”.  That is, one whose appearance and persistence is dependent on disturbance due to its inability to compete with other vegetation.  In the northern parts of its range it seems to be a more permanent member of the floral communities.

Native Americans used this species as a source of fibers and during the Second World War children in the northern states were encouraged to collect the seed pods that were processed for the coma, or floss, which was used for floatation in life vests. Today the coma is harvested for use in pillows and comforters.

According to the Field Guide to Medicinal Wild Plants or Edible Wild Plants, common milkweed is edible only under certain circumstances.  Boiling can eliminate the bitter taste and toxicity of the sap, but this must be done very carefully to avoid the toxins.  Eating milkweed is not recommended.


Distribution: AL, AR, CT, DC, DE, GA, IA, IL, IN, KS, KY, LA, MA, MD, ME, MI, MN, MO, MS, MT, NC, ND, NE, NH, NJ, NY, OH, OK, OR, PA, RI, SC, SD, TN, TX, VA, VT, WI, WV

Canada: MB, NB, NS, ON, PE, QC, SK

Flower: Slightly pendulous spherical umbels with as many as 100 flowers per umbel, but usually 30+/- flowers.  3+/- umbels per stem. Pedicels are 1 1/2 in (4 cm) long. Petals up to 1/3 in (9mm) long. Hoods and horns are white or purple. Corolla reflexes backward to expose the hoods and horns.  Horn protrudes through the hoods.

Foliage: Stem is stout and erect. Stem color varies from green to purplish. Fine white hairs cover the plant except the flowers. Leaf arrangement is opposite and attachment is sessile or petiolate with a short petioles.

Habitat: Open spaces, croplands, fields, meadows, prairies, railroads, waste ground, roadsides and a wide array of disturbed sites.

Height: Typically 3-5 feet (90-150 cm) but can reach 8 feet (240 cm) in ditches and gardens.

Leaves: 4-7 ½ in (10-19 cm) long and 2-4 1/3 in (5-11 cm) wide. Shape is variable and is described as ovate, oblong, lanceolate or elliptic.  The rich dark green of the top of the leaves contrasts with a lighter green on the underside. Leaf pairs often perpendicular to each other with short petioles.

Roots: Moderately deep rooted with a broad net work of lateral roots (rhizomes) on established plants that give rise to ramets (stems) forming clones of genetically identical individuals.

Toxicity: Moderate.


Blossoming Season: May – August.

Life span: NA

Propagation: Seed. Spreads via rhizomes and forms small to large clones. Rhizomes can be cut and transplanted early in the spring.

Pods: Approximately 3 ½ in (9 cm) long to 1 2/3 in (4 cm) at the widest point. Pod color is grayish and is thick at the base and tapers down to a narrow tip. Pods are covered with hair and soft spikes.  Pods split open between September-October.

Seed Color: Light brown.

Environment and Growth Requirements

Maintenance: Low.

Overhead Conditions: Not shade tolerant.  Needs lots of sunlight.

Precipitation: 20-60 in (51-153 cm) annually.

Soil Texture: Medium to fine sandy, clayey, or rocky calcareous soils. Also found in well-drained loamy soils.

Temperature: Can tolerate a minimum temperature of –40 to –30 Fahrenheit (-40 to -34 Celsius).

Work Cited:,,,,, (Ohio Experiment Station: Bulletin), (Perennial Weeds)

Photo: Monarch Watch Archive