NPS Photo Common Milkweed (Asclepias syriaca) This native host plant for the Monarch butterfly is named for its milky sap which contains toxic chemicals. Monarch caterpillars feed on milkweed and store the toxins in their tissues. The toxins make both the caterpillars and the butterflies distasteful to potential predators. In late summer, the plant’s seedpods open and the fluffy seeds are borne on the wind to grow in new areas. |
Last updated: February 3, 2025