Toxic Parts:
all, dry
cardiac glycosides
Flower Color:
  • flower color
  • flower color
meadows, haybales, ornamental

Time of Greatest Risk


Geographical Distribution

Common milkweed distribution - United States

Related Species

Common Milkweed

Asclepias syriaca

Cottonweed, Silkweed, Virginia Silk, Wild Cotton
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Common milkweed (Asclepias syriaca ) is an erect-stemmed, herbaceous perennial plant from the Apocynaceae family. It is often thought of as a weed, due to its ability to spread rapidly through underground rhizomes. Common milkweed is native to eastern North America and is most commonly found growing in poor, dryish soils in fields, open woods, waste areas, roadsides, and alongside railroad tracks.

Common Milkweed Toxic Components

All parts of common milkweed contain cardiac glycosides, resinoids and alkaloids. Horses need only consume 0.005 to 2% of their body weight to be poisoned.

What Common Milkweed Looks Like

Common milkweed produces clusters of pink to mauve-white flowers which bloom June to August. Milkweed fruits are spindle-shaped follicles covered with silky white hairs. Milkweed stems and leaves contain a thick, white, milky sap throughout the plant which seeps out when the plant is damaged.


  • Dullness
  • Depression
  • Dilated Pupils
  • Spasms
  • Difficulty Breathing
  • Weakness
  • Inability To Stand Or Walk
  • Colic
  • Irregular Heart Rate
  • Uncoordinated Gait
  • Labored Breathing
  • High Body Temperature
  • Rapid And Weak Pulse
  • Coma


CHEMICAL CONTROL: Milkweed is tolerant of most herbicides. Control requires multiple herbicide applications. Best if applied when milkweed is in the late-bud to flowering stage and actively growing. Patch-spray Roundup at 6 to 8 pt/A (up to 10pt/A is allowed). Apply Roundup with AMS at 8.5 lb/100 gallons of water.