Asclepias tuberosa (butterflyweed) is an Ontario native plant/milkweed that is essential for the survival of the Monarch butterfly. The Monarch butterfly larvae lay their eggs on Asclepias tuberosa and the larvae emerge to feed on the leaves. In full sun Asclepias tuberosa flowers for many months followed by decorative, green seed pods. It emerges from winter dormancy very late. Be patient. It begins to grow with warmer weather.