Butterfly Milkweed (Asclepias tuberosa)

 

Butterfly Milkweed (Asclepias tuberosa)

Butterfly milkweed is a perennial wildflower native to Wisconsin and much of eastern and central North America. It typically grows one to two feet tall and forms a compact, upright clump topped with bright orange to yellow‑orange flower clusters. These clusters are usually two to five inches across and appear at the ends of the stems in early to midsummer. Each flower has the characteristic milkweed structure, with a five‑part crown, though the blossoms are smaller and more densely arranged than those of common milkweed.

The leaves are stiff, dark green, and lance‑shaped, ranging from two to six inches long. They are toothless, alternate or sometimes spirally arranged, and attached to stems that are also firm and hairless or only lightly hairy. Unlike most other milkweeds, butterfly milkweed does not produce milky sap; instead, it exudes a clear sap when cut, a trait that often surprises people familiar with the genus.

This species grows best in full sun and well‑drained soils, including sand, loam, clay, and even limestone‑derived substrates. Once established, it is highly drought‑tolerant thanks to a deep, woody taproot. Its tidy form and resilience make it a reliable choice for native gardens, prairie restorations, and sunny roadside plantings, especially in Wisconsin’s variable summer conditions.

Ecologically, butterfly milkweed is an important nectar source for butterflies, bees, and other pollinators. Monarch butterflies lay their eggs on it, and the caterpillars feed on its foliage just as they do with other milkweed species. Its long bloom period and abundant nectar make it one of the most visited milkweeds in prairie landscapes.

Sources:

Lady Bird Johnson Wildflower Center — Asclepias tuberosa Illinois Wildflowers — Asclepias tuberosa (Butterfly Milkweed) Minnesota Wildflowers — Asclepias tuberosa USDA NRCS Plants Database — Asclepias tuberosa Wisconsin State Herbarium — Asclepias tuberosa

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