Asclepias subverticillata, or Horsetail Milkweed, grows up to 4 ft tall and has very narrow whorled leaves. It prefers disturbed habitats such as roadsides, sandy flats, or grasslands between 3000-8000 ft. Its cream-colored flowers bloom between June-September. This is a host plant for monarch and queen butterfly larvae. Plant in partial to full sun, wet to dry conditions. Transplants well due to its fibrous root system in any soil type. Tolerates standing water.