Milkweeds are very beneficial to butterfly populations. The Swamp Milkweed grows later in the spring, has narrow leaves, and finally a clump of foliage. From then umbels of fragrant, pink to mauve flowers appear that are so generous with nectar that they attract pollinators of all kinds.
The Swamp Milkweed is the choice plant for Monarch butterflies as their caterpillars feed on the leaves of this milkweed. The roots of this plant have evolved to thrive in low oxygen environments, including the wet soil found around lakes and streams. The plants can reach 2m (6') in height, and will grow in full sun to partial shade.