Asclepias tuberosa

It is a perennial plant growing to 0.3–1 metre (1 ft 0 in–3 ft 3 in) tall, with clustered orange or yellow flowers from early summer to early autumn. The leaves are spirally arranged, lanceolate, 5–12 cm (2" to 5") long, and 2–3 cm (about 1") broad.

Some wild plants have been reported to have orange flowers that are very reddish. It is uncertain if this is due to soil mineral content, ecotype genetic differentiation, or both. A cultivar, "Hello Yellow", typically has more yellowish flowers than ordinary examples of this plant.

This plant favors dry, sand or gravel soil, but has also been reported on stream margins. It requires full sun.

The plant looks similar to the lanceolate milkweed (Asclepias lanceolata), but is uniquely identified by the larger number of flowers, and the hairy stems that are not milky when broken. It is most commonly found in fields with dry soil.

Most easily propagated by seed. The primary pollinators are bees and wasps, rather than butterflies.[7] Sown outdoors after frost, a plant will flower and produce seed in the third year. Difficult to transplant once established.[8][9] In cultivation in the greenhouse, plants can easily be grown from seed to flowering in as little as three to six months.

• Asclepias tuberosa subsp. interior – (Central United States, Ontario and Quebec[10])
• Asclepias tuberosa subsp. rolfsii – Rolfs milkweed (Southeastern United States)
• Asclepias tuberosa subsp. tuberosa – (Eastern United States)

Common names include butterfly weed,[11] Canada root, chieger flower,[11] chiggerflower, fluxroot, Indian paintbrush, Indian posy, orange milkweed, orange root,[12] orange Swallow-wort, pleurisy root,[11] silky swallow-wort, tuber root, yellow milkweed, white-root, windroot, butterfly love, butterflyweed, and butterfly milkweed.[13]

The plant contains toxic glycosides, alkaloids and resinoids which can cause weakness or seizures.[14]

Native Americans and European pioneers used the boiled roots to treat diarrhea and respiratory illnesses.[15] The young seed pods were used as food after being boiled in several changes of water.[15] The seed pod down was spun and used to make candle wicks.[15]

Use of the plant is contraindicated in pregnancy, during lactation or with infants due to its toxins, which include resinoids and pregnanes.[16] Because monarch butterflies do not favor it when reproducing, it is not as suitable for use in butterfly gardens and monarch waysides as are other milkweed species.[5][6]

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  Entire plant from the ground to the flower
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  Young stems during spring
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  A young leaf
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  An emerging flower head
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  Closeup of the hairy stems
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  Closeup of unopened buds
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  Flower head
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  Closeup showing unopened, opening, and fully opened flower buds
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  Orange flowers
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  Red-striped orange flowers
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  Yellow flowers
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  Seedpod
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• Peterson, Roger Tory; Margaret McKenny (1968). A Field Guide to Wildflowers of Northeastern and North-central North America. Boston: Houghton Mifflin Company. ISBN 978-0-395-18325-0.
• Photo of a J.J. Audubon Plate Clay-Colored Sparrow perched atop Asclepias tuberosa

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• Butterfly weed brief information and pictures
• Missouri Botanical Garden Asclepias tuberosa