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A Comprehensive Guide to Bear Mountain Milkweed (Asclepias scaposa)

Bear Mountain Milkweed (Asclepias scaposa) is a herbaceous perennial that is native to the state of Texas in the United States. This plant is a host to the Queen (Danaus gilippus) and Monarch (Danaus plexippus) butterflies. Growing from 2 inches to 1 foot tall, this species has cream to rose/purple colored flowers that bloom from March to October. It is hardy in zones 8-10.

Taxonomy and Naming of Bear Mountain Milkweed (Asclepias scaposa)

Herbarium specimen of bear mountain milkweed (Asclepias scaposa).
Herbarium Specimen of Bear Mountain Milkweed (Asclepias scaposa) — University of Texas Herbarium – CC0 1.0

Taxonomy

Bear Mountain Milkweed (Asclepias scaposa) was originally named and described by Anna Murray Vail, an American botanist, in 1898 based on a specimen in the state of New Mexico (Vail 1898). However, a later Flora in New Mexico (Wooton and Standley 1915) states this species is not in the state. This species still uses this name and is a member of the Dogbane Family (Apocynaceae).

Meaning of the Scientific and Common Names

Scientific Name

The genus name, Asclepias, is named for the Greek god of healing, Asklepios (Flora of Wisconsin). The species name, scaposa, is Latin for “stem.”

Common Name and Alternative Names

The common name comes from the location of the plant.

Physical Description of Bear Mountain Milkweed (Asclepias scaposa)

Plant of bear mountain milkweed (Asclepias scaposa) in rocky habitat.
Bear Mountain Milkweed in Rocky Habitat — © Michelle some rights reserved

Description

  • Plant Type: This plant is a herbaceous perennial
  • Height: up to 1 foot
  • Stem: The stem is simple, branched, ascending, and slightly pubescent.
  • Leaves: The leaves are opposite, entire, and oval to oblong-elliptic (Singhurst and Hutchins 2015). They range from 1 to 2.5 inches long and 1 inch wide. The leaves are coriaceous and pubescent (Vail 1898).
  • Flower color: rose to purple (Singhurst and Hutchins 2015 and Woodson 1954) to white (Vail 1899)
  • Blooming period: This plant blooms from March to October.
  • Fruiting type and period: This plant has follicles that mature in the late summer and fall.

Range of Bear Mountain Milkweed (Asclepias scaposa) in the United States and Canada

Range map of Bear Mountain Milkweed (Asclepias scaposa) in the United States and Canada.
Range Map Credit: Kartesz, J.T., The Biota of North America Program (BONAP). 2023.(website https://bonap.org/). Chapel Hill, N.C. [maps generated from Kartesz, J.T. 2023. Floristic Synthesis of North America, Version 1.0. Biota of North America Program (BONAP). (in press)]

This milkweed species is native to the state of Texas in the United States and to Mexico.

Habitat

Desert habitat in southwest.
Patrick Alexander from Las Cruces, NM, CC0 1.0, via Wikimedia Commons

This species grows in shrubland openings that are gravelly, talus slopes Singhurst and Hutchins 2015) and mountainsides (Woodson 1954).

Hosted Insects

Queen Butterfly on Twig.
Queen Butterfly (Danaus gilippus) — Korall, CC BY 3.0, via Wikimedia Commons

Other Supported Wildlife

Bumblebee on pink flower.
Bumblebee on Flower — Weerlicht, CC0, via Wikimedia Commons

This species is a nectar source to other butterflies, skippers, bees, and wasps during the growing season.

Frequently Asked Questions about Bear Mountain Milkweed (Asclepias scaposa)

Is this plant poisonous?

Like other milkweeds, it has cardiac glycosides (cardenolides) and is considered to be poisonous with ingestion.

Does this plant have any ethnobotanical uses?

The Native American Ethobotanical Database does not specifically mention this species, but milkweeds in general have been used for pharmaceuticals, foods, and fibers.

How is this plant distinguished from other milkweeds?

This plant is considered to be unique among the milkweeds (Singhurst and Hutchins 2015). The short stature and small inflorescence can readily identify this plant.

Is this plant invasive?

This plant is not considered to be invasive and is fairly restricted in habitat.

Gardening with Bear Mountain Milkweed (Asclepias scaposa)

Herbarium specimen of bear mountain milkweed (Asclepias scaposa).
Herbarium Specimen of Bear Mountain Milkweed — University of Texas Herbarium – CC0 1.0

Hardiness

This species is hardy in zones 8-10. If your garden is within these zones and you have the right growing conditions (soil, moisture and exposure), you may well be able to grow this plant. However, if planted outside of its range, the hosted species may not recognize the plant or be harmed by ingesting a different species with an unfamiliar chemical composition.

Optimal Conditions

This species grows best in places where there is a lot of moisture and gets full to partial sun.

Additional Notes about this Plant

This species of milkweed is restricted in range and is not in cultivation.

References

  • Singhurst, Jason, Ben Hutchins, and Walter Holmes. 2015. Identification of Milkweeds of Texas. Texas Parks and Wildlife Department.
  • Vail, Anna Murray. 1899. Studies in the Asclepiadaceae- IV. Notes on some Old Types, with descriptions of new or little known species. Bulletin of the Torrey Botanical Club 26: 423-431.
  • Vail, Anna Murray. 1898. Studies in Asclepiadaceae. – III. Bulletin of the Torrey Botanical Club 25 (4): 171-182.
  • Woodson, Robert E. 1954. The North American Species of Asclepias L. Annals of the Missouri Botanical Garden 41: 1-211.
  • Wooton, E.O. and Stanley Paul Carpenter. 1915. Flora of New Mexico. Contributions from the United States National Herbarium v. 19.
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Robert Coxe

Robert Coxe

Robert Coxe is a professional ecologist and botanist who has worked as the State Ecologist of Delaware and as an ecologist for the Western Pennsylvania Conservancy. He is also a former Past-President of the Pennsylvania Academy of Science. He currently is an innkeeper at McMullen House Bed & Breakfast LLC and a web designer and owner for Silphium Design LLC.

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