Toxic Parts:
all parts
cardiac glycosides
Flower Color:
  • flower color
  • flower color
woodlands, meadows, haybales

Time of Greatest Risk


Geographical Distribution

Whorled Milkweed  distribution - United States

Related Species

Whorled Milkweed

Asclepias verticillata

Horsetail Milkweed
8/ 10
Whorled milkweed (Asclepias verticillata) is an erect, single-stemmed, often unbranched perennial herb that is from the Milkweed (Asclepiadaceae) family. Whorled milkweed attributes:
  • Height: 1 to 3 feet
  • Leaves: Narrow, needlelike; set in whorls of 3 to 7 intervals, often are crowded close together on the tips of stems, giving a "horsetail" appearance.
  • Flowers: Dense, flat-topped clusters of greenish-white flowers which bloom from late spring to the fall.
  • Fruit: Narrow, spindle-shaped pods that are about 2 to 3 inches long.
  • Roots: Slender, fibrous roots
Toxic components
All milkweed Asclepias species are toxic to horses if ingested, as they contain cardiac glycosides. Whorled milkweed and other whorled-leaf types such as horsetail milkweed are even more toxic because they additionally contain a lethal neurotoxin.


  • Severe Colic
  • Dilated Pupils
  • Incoordination
  • Muscle Tremors
  • Falling
  • Violent Convulsions
  • Respiratory Failure
  • Death Within 24 Hours


CHEMICAL: herbicides can be an effect method of control of whorled milkweed.