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A Comprehensive Guide to Slim Milkweed (Asclepias linearis)

Slim Milkweed (Asclepias linearis) 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 0.5 to 2 feet tall, this species has white to green flowers that bloom from April to August. It is hardy in zones 8-10.

Taxonomy and Naming of Slim Milkweed (Asclepias linearis)

Herbarium specimen of slim milkweed (Asclepias linearis).
Herbarium Specimen — Asclepias linearis Scheele collected in United States of America by The New York Botanical Garden (licensed under CC BY 4.0)
Isotype of slim milkweed (Asclepias linearis).
Isotype Specimen — Harvard University Public Domain


Slim Milkweed (Asclepias linearis) was originally named and described by George Heinrich Adolf Scheele, a German botanist, in 1848. The description was based on a specimen collected in New Braunfels, Texas (Scheele 1848). This species has kept the same name since this time 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, linearis, is Latin for linear, and is in reference to the leaves.

Common Name and Alternative Names

The common name comes from the slim appearance of the plant.

Physical Description of Slim Milkweed (Asclepias linearis)

Plant of slim milkweed (Asclepias linearis) in an open area.
Plant of Slim Milkweed — Asclepias linearis Scheele observed in United States of America by alymharmon (licensed under CC0 1.0)


  • Plant Type: This plant is a herbaceous perennial
  • Height: 0.5 to 2 feet
  • Stem: The stem is stout and slightly pubescent (Woodson 1954).
  • Leaves: The leaves are opposite, sessile, simple, entire, and linear in shape. The leaves are 1 to 3.5 inches long and about 0.04 to 0.16 inches wide.
  • Flower color: greenish-white
  • Blooming period: This plant blooms from April to October (Singhurst and Hutchins 2015).
  • Fruiting type and period: This plant has follicles that mature in the late summer and fall.

Range of Slim Milkweed (Asclepias linearis) in the United States and Canada

Range of slim milkweed (Asclepias linearis) in the United States and Canada.
Range Map Credit: Kartesz, J.T., The Biota of North America Program (BONAP). 2023.(website 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 is also located in Mexico.


Prairie habitat in United States.
Prairie Habitat — USFWS Mountain-Prairie, Public domain, via Wikimedia Commons

This species grows in dry prairies (Woodson 1954), bluestem prairie (Harcombe and Neaville 1977) and wetlands (Rosen 2007). This species can be found on the Walnut Formation, a geological formation (Swadek and Burgess 2012).

Hosted Insects

Queen Butterfly on Twig.
Queen Butterfly on Vegetation — Korall, CC BY 3.0, via Wikimedia Commons

Other Supported Wildlife

Bumblebee on pink flower.
Bee Nectaring on Pink Flower — Weerlicht, CC0 1.0, via Wikimedia Commons

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

Frequently Asked Questions about Slim Milkweed (Asclepias linearis)

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 foods, pharmaceuticals, and fibers.

How is this plant distinguished from other milkweeds?

This species is similar to the whorled milkweed (Asclepias verticillata), but the leaves are not in whorls and the stems are often branched at the base (Quillin 1922). Slim milkweed was considered at one point to be the same species as whorled milkweed, but he instead opted to keep it as its own species (Woodson 1954). Slim Milkweed has also been a variety under whorled milkweed (Pollard 1897). The lack of whorled leaves also separates this species from horsetail milkweed (Asclepias subverticillata).

Is this plant invasive?

This plant has not been described as invasive in the literature.

Gardening with Slim Milkweed (Asclepias linearis)

Whitish flower cluster of slim milkweed (Asclepias linearis).
Flower cluster of Slim Milkweed — Asclepias linearis Scheele observed in United States of America by Michelle (licensed under CC BY 4.0)


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 it can receive full sun and has dry soil.


  • Harcombe, P.A. and J.E. Neaville. 1977. Vegetation Types of Chambers County, Texas. The Texas Journal of Science 29: 209-234.
  • Pollard, Charles Louis. 1897. Studies in the Flora of the Central Gulf Region – I. Bulletin of the Torrey Botanical Club 24(3): 148-157.
  • Quillin, Ellen Schultz. 1922. 500 Wildflowers of San Antonio and vicinity. (San Antonio, TX: self-published).
  • Rosen, David J. 2007. The Vascular Flora of Nash Prairie: A Coastal Prairie Remnant in Brazoria County, Texas. Journal of the Botanical Research Institute of Texas. 1: 679-692.
  • Scheele, George Adolf. 1848. Beitrage zur Flor von Texas. Linnaea: Ein Journal fur die Botanik in ihrem ganzen Unfange 21(5): 737-768.
  • Singhurst, Jason and Ben Hutchins. 2015. Identification of Milkweeds in Texas. Lady Bird Johnson Wildflower Center and Texas Parks and Wildlife.
  • Swadek, Rebecca K. and Tony L. Burgess. 2012. The Vascular Flora of the North Central Texas Walnut Formation. Journal of the Botanical Research Institute of Texas. 6(2): 725-752.
  • Woodson, Robert E. 1954. The North American Species of Asclepias L. Annals of the Missouri Botanical Garden 41: 1-211.
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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.