Asclepias verticillata (Whorled Milkweed or Horsetail Milkweed) is a particular kind of milkweed used as a medicinal plant. It is native to North America. It blooms in the summer. The flowers are white or pale green. It is found in fields, open woodlands, and prairies. Whorled Milkweed likes dry soil and sunny or partly shaded places. It grows from 0.3 to 0.9 meters tall (1–3 feet).