Species is US Native, not introduced alien Seed Packet designed for 15 Square Feet of Planting Monarch larva can only feed on milkweed plants. Swamp Milkweed is a host plant and food source for Monarch larva and nectar source for adult Monarchs. Swamp Milkweed is a 4' to 5' tall native perennial with bright pink showy clusters of pink and white flowers. As its name implies it prefers moist sites such as wet grasslands, stream banks, wet open woods, swamp and marsh edges and wet ditches; however, it will grow in seasonally dry areas. Swamp Milkweed grows in full sun or part shade. Except for a few west coast states it is distributed over all of the US. The conspicuous flowers make this a great garden plant for pond edges, detention areas, or other wet soil site. It is normal inclusion in wetland reclamation and remediation mixtures as well as wildlife seed mixtures. It is deer resistant but is an important food and larval host plant for a large number of pollinator species.