Table of Contents for Engelmann’s Milkweed (Asclepias engelmanniana)
Engelmann’s Milkweed (Asclepias engelmanniana) is a herbaceous perennial that is native to the south-central, mid-west, and southwestern regions of the United States. This plant is a host to the Queen (Danaus gilippus) and Monarch (Danaus plexippus) butterflies. Growing from 2 to 5 feet tall, this species has greenish-yellow to purplish flowers that bloom from May to September. It is hardy in zones 4-9.
Taxonomy and Naming of Engelmann’s Milkweed (Asclepias engelmanniana)
Taxonomy
Engelmann’s Milkweed (Asclepias engelmanniana) was originally named and described by Georg Engelmann, a German-American botanist, as Acerates auriculata. After going through a succession of names it was given its current name in 1941 by Robert Woodson. The species has kept this 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, engelmanniana, is a Latinized form of the describer of the plant.
Common Name and Alternative Names
The common name comes from the original describer of the species, Georg Engelmann.
Physical Description of Engelmann’s Milkweed (Asclepias engelmanniana)
Description
- Plant Type: This plant is a herbaceous perennial
- Height: 2 to 5 feet
- Stem: The stem is simple and glabrous.
- Leaves: The leaves are alternate, sessile, simple, entire, and linear in shape. The leaves are 2 to 10 inches long and about 0.04 to 0.3 inches wide. The margins of the leaves can be revolute (Marsh and Clawson 1921).
- Flower color: greenish-yellow to purplish
- Blooming period: This plant blooms from May to September.
- Fruiting type and period: This plant has follicles that mature in the late summer and fall.
Range of Engelmann’s Milkweed (Asclepias engelmanniana) in the United States and Canada
This milkweed species is native in the south-central, mid-west, and southwestern United States. It is considered rare in the states of Wyoming and Iowa.
Habitat
This species grows in dry prairies, plains, canyons, along creeks and in open woodlands that have limestone or sandy soils.
Hosted Insects
This species is a host for the Monarch Butterfly (Danaus plexippus), the Queen Butterfly (Danaus gilippus).
Other Supported Wildlife
This species is a nectar source to other butterflies, skippers, bees, and wasps during the growing season.
Frequently Asked Questions about Engelmann’s Milkweed (Asclepias engelmanniana)
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 shows that this plant has been used as a respiratory aid.
How is this plant distinguished from other milkweeds?
This milkweed is similar to Rusby’s milkweed (Asclepias rusbyi), but are different in the anther wings. Rusby’s milkweed has slightly curved wings and whereas this milkweed has prominently arched wings (Rintz 2014). Another treatment from Texas, states that this species can be separated by the distinguishing narrow leaves (Singhurst and Hutchins 2015).
Is this plant invasive?
This plant has not been shown to be invasive in the literature.
Gardening with Engelmann’s Milkweed (Asclepias engelmanniana)
Add Engelmann’s Milkweed to Your Garden
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Hardiness
This species is hardy in zones 4-9. 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 it can receive full sun and has dry sandy and/or limestone soils.
References
- Rintz, Richard F. 2014. A closer look at Asclepias engelmanniana Woodson and Asclepias rusbyi (Vail) Woodson (Apocynaceae, Asclepiadoideae). Phytologia 96(4): 241-246.
- Singhurst, Jason and Ben Hutchins. 2015. Identification of Milkweeds in Texas. Lady Bird Johnson Wildflower Center and Texas Parks and Wildlife.
- Woodson, Robert E. 1954. The North American Species of Asclepias L. Annals of the Missouri Botanical Garden 41: 1-211.
