Swamp milkweed (Asclepias perennis) is an erect, herbaceous perennial wildflower that occurs naturally in floodplain swamps, marshes and wet ditches, and along riverbanks. It typically blooms in late spring through early fall and attracts many pollinators. Like all members of the Asclepias genus, it is a larval host plant for Monarch, Queen and Soldier butterflies. The plant contains a milky latex that is toxic to most animals, but Monarch, Queen and Soldier caterpillars are adapted to feed on them despite the chemical defense. The flowers are an important nectar source for native bees, wasps and butterflies.