This native perennial plant is about 2-3' tall and unbranched. The central stem is light green, round, and glabrous or slightly pubescent. The opposite leaves are up to 6" long and 3" across. They are ovate-oblong or broadly lanceolate, with smooth margins that may undulate up and down. The leaves often curl upward from the pinkish central vein. The upper surface of the foliage is mostly glabrous and yellowish green to dark green (depending on light conditions), while the lower surface is light green and softly pubescent. The central stem terminates with 1-6 umbels of flowers; there may be a few axillary umbels from some of the upper leaves as well. Each rounded umbel is about 3" across. These flowers have the typical structure for milkweeds, and can be pale to deep purple in appearance, often with greenish or rosy tints. However, the central reproductive column and base of the deflexed petals are white. The hoods are much taller than the horns; the latter curve inward toward the reproductive column and appear spike-like (but are thicker toward the base). The blooming period occurs from late spring to mid-summer, and lasts about 1-2 months. The flowers have a pleasant fragrance. If pollination occurs, the flowers are replaced by seedpods (follicles) that are held erect and are spindle-shaped. These seedpods are up to 6" long and 1" across, and tapered on both ends. They have a smooth surface and are finely pubescent. The seeds have large tufts of white hair, and are distributed by the wind. The root system consists of a fleshy taproot and short rhizomes; small clumps of plants can be produced vegetatively.