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A Comprehensive Guide to Sperry’s Milkweed (Asclepias sperryi)

Sperry’s Milkweed (Asclepias sperryi) is a herbaceous perennial that is native to the state of Texas in the United States and adjacent Mexico. This plant is a host to the Queen (Danaus gilippus) and Monarch (Danaus plexippus) butterflies. Growing from 4 inches to 1 foot tall, this species has greenish-yellow to white colored flowers that bloom from April to August. It is hardy in zones 7-8.

Taxonomy and Naming of Sperry’s Milkweed (Asclepias sperryi)

Herbarium specimen of Sperry's milkweed (Asclepias sperryi).
Herbarium Specimen — Asclepias sperryi Woodson collected in United States of America by The New York Botanical Garden (licensed under CC BY 4.0)

Taxonomy

Sperry’s Milkweed (Asclepias sperryi) was originally named and described by Robert Woodson, an American botanist, in 1941. 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, sperryi, is a Latinized name for the collector of the plant.

Common Name and Alternative Names

The common name comes from the original collector of the plant, Omer E. Sperry (Woodson 1941).

Physical Description of Sperry’s Milkweed (Asclepias sperryi)

Herbarium specimen of Sperry's milkweed (Asclepias sperryi).
Herbarium Specimen — Harvard University, Public Domain

Description

  • Plant Type: This plant is a suffretescent (semi-shrub).
  • Height: 4 inches to 1 foot tall
  • Stem: The stems are clustered from the roots and are generally glabrous (Woodson 1954).
  • Leaves: The leaves are opposite, simple, sessile, entire, and filiform (Woodson 1954). They range from 2 to 3 inches long and 0.1 inch wide and glabrous with revolute margins (Woodson 1954).
  • Flower color: greenish-yellow to white, sometimes with a purple tinge (Woodson 1954).
  • Blooming period: This plant blooms from April to August.
  • Fruiting type and period: This plant has follicles that mature in the late summer and fall.

Range of Sperry’s Milkweed (Asclepias sperryi) in the United States and Canada

Range map of Sperry's Milkweed (Asclepias sperryi) 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

Dry grassland in American west.
Dry Grassland — “Comanche National Grassland” by cm195902 is licensed under CC BY 2.0.

This species grows in grasslands that have limestone (Singhurst and Hutchins 2015) and limestone slopes (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 Sperry’s Milkweed (Asclepias sperryi)

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 milkweed is most similar to the long-hood milkweed (Asclepias macrotis), but can be told apart by the hoods. The hoods in Sperry’s milkweed have a deflexed base, while the long-hood milkweed has an ascending-spreading base (Singhurst and Hutchins 2015). This milkweed is also similar to the talayote (Asclepias fournieri) and another milkweed (Asclepias zanthodacryon), which occur in Mexico. However, both of these species are herbaceous, whereas this species is a semi-shrub. In addition, the one flowered cyme is distinctive to this plant.

Is this plant invasive?

This plant is not considered to be invasive and has a restricted distribution.

Gardening with Sperry’s Milkweed (Asclepias sperryi)

Herbarium specimen of Sperry's milkweed (Asclepias sperryi).
“03257157.tif” – Asclepias sperryi Woodson collected in Mexico (licensed under CC0 1.0)

Hardiness

This species is hardy in zones 7-8. 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 with full sun to part-shade and has high pH medium moisture soil.

References

  • Singhurst, Jason, Ben Hutchins, and Walter Holmes. 2015. Identification of Milkweeds of Texas. Texas Parks and Wildlife Department.
  • Woodson, Robert E. 1954. The North American Species of Asclepias L. Annals of the Missouri Botanical Garden 41: 1-211.
  • Woodson, Robert E. 1941. Two New Asclepiads from the Southwestern United States. Annals of the Missouri Botanical Garden 28: 245-248.
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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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