Asclepias tuberosa subsp. interior

Species Native to Missouri
Common Name: butterfly milkweed 
Type: Herbaceous perennial
Family: Apocynaceae
Native Range: North America
Zone: 3 to 9
Height: 1.00 to 2.50 feet
Spread: 1.00 to 1.50 feet
Bloom Time: June to August
Bloom Description: Orange to yellow-orange
Sun: Full sun
Water: Dry to medium
Maintenance: Low
Suggested Use: Naturalize, Rain Garden
Flower: Showy
Attracts: Butterflies
Tolerate: Deer, Drought, Erosion, Dry Soil, Shallow-Rocky Soil

Culture

Easily grown in average, dry to medium, well-drained soils in full sun. Drought tolerant. Does well in poor, dry soils. New growth tends to emerge late in the spring. Plants are easily grown from seed, but are somewhat slow to establish and may take 2-3 years to produce flowers. Mature plants may freely self-seed in the landscape if seed pods are not removed prior to splitting open. Butterfly weed does not transplant well due to its deep taproot, and is probably best left undisturbed once established.

Noteworthy Characteristics

Asclepias tuberosa, commonly called butterfly weed, is a tuberous rooted, Missouri native perennial which occurs in dry/rocky open woods, glades, prairies, fields and roadsides throughout the State (Steyermark). It typically grows in a clump to 1-2.5' tall and features clusters (umbels) of bright orange to yellow-orange flowers atop upright to reclining, hairy stems with narrow, lance-shaped leaves. Unlike many of the other milkweeds, this species does not have milky-sapped stems. Flowers give way to prominent, spindle-shaped seed pods (3-6" long) which split open when ripe releasing numerous silky-tailed seeds for dispersal by the wind. Seed pods are valued in dried flower arrangements. Long bloom period from late spring throughout the summer. Flowers are a nectar source for hummingbirds, butterflies and many other pollinators, and leaves are a food source for monarch butterfly larvae (caterpillars).

The subspecies interior differs from the species primarily in its geographic range and habitat, being primarily found in prairies in the central and southwestern United States, from the Rocky Mountains south to northern Mexico and north to southern Ontario. The foliage of this subspecies may differ slightly from the species, generally exhibiting a narrower, lanceolate to linear-lanceolate leaf blade shape and obtuse to truncate leaf bases. However, natural variation in leaf morphology can render these differences meaningless for the purposes of identification.

Genus name honors the Greek god Asklepios the god of medicine.

The specific epithet tuberosa means "tuberous" in reference to the roots.The infraspecific epithet interior refers to the native range of this subspecies which does not include coastal regions of the continent.

The common name butterfly weed refers to how attractive this plant is to butterflies. This species is sometimes also called pleurisy root in reference to a traditional medicinal use of the plant roots to treat lung inflammations.

Problems

No serious insect or disease problems. Crown rot can be a problem in wet, poorly drained soils. Susceptible to rust and leaf spot.

Uses

Butterfly gardens, rock gardens, meadows, prairies, or naturalized/native plant areas. Also effective in sunny borders or slopes. Whether massing plants in large drifts or sprinkling them throughout a prairie or meadow, butterfly weed is one of our showiest native wildflowers.