Mead's Milkweed - Asclepias meadii
Mead's milkweed once flourished in the tallgrass prairies of the Midwestern United States, including most of Missouri. As prairie habitat disappeared, populations of Mead's milkweed became restricted to tallgrass prairie remnants and scattered rhyolite glades in the Ozarks. In addition to habitat loss, this plant is threatened by erosion, herbicides, overgrazing, and invasion by non-native plants. Mead's milkweed is listed ENDANGERED by the Missouri Department of Conservation and THREATENED by the U.S. Fish and Wildlife Service.
Identification
![[drawing of Mead's milkweed]](images/milk2.gif)
Mead's milkweed is a herbaceous, erect plant growing 1 to 2 feet tall. It has a smooth stem with milky sap and 2 to 6 pairs of opposite, narrow, tapering leaves. This perennial plant blooms from late May to mid-June, producing one or two cluster of flowers at the top of its stem. Each cluster has an average of 5 to 14 flowers. The flowers are yellow-green or greenish cream and are often tinged with purple. Individual flowers have five tubular hood-shaped structures with a slender "horn" extending from each one.
Seeds mature from July to October. Pods are green and gradually become darker as they mature, growing to be 1 1/2 to 4 inches long. A single plant may have multiple stems, which can be mistaken for individual plants. Each stem produces flowers for 2 to 3 years and then becomes dormant or disappears.
For a technical description of this plant, refer to:
Steyermark, J.A. 1963. Flora of Missouri. Iowa State Press. Ames, Iowa. 1728 pp.
Habitat and Distribution
![[Missouri map of Mead's milkweed distribution]](images/milk3.gif)
Mead's milkweed is native to dry or mesic (dry most of the year, but retain water during part of the year) prairies and igneous glades (thin-soiled glades with rocky outcrops). This plant is commonly found in the following areas: mesic to dry tallgrass and upland prairies with sandstone or chert bedrock, prairie hay meadows, railroad right-out-way prairie remnants, virgin mesic silt loam prairies, and in igneous glades.
Historically, natural prairie habitat was abundant, and Mead's milkweed ranged throughout much of Missouri. It is presently found in the Osage Plains region and the St. Francois mountains region of the Ozarks. Approximately 46 sites exist in Missouri, some of which are on protected prairies. However, 85% of the known populations of Mead's milkweed are on privately owned land and receive little or no protection.
Cause of Historic Decline
Mead's milkweed was historically abundant and common in native prairie habitats. Declines in population were a result of habitat loss as native prairies were converted to agricultural and urban uses. Close to 99 percent of the Midwest's original 18 million acres of tallgrass prairie have been destroyed. In addition, herbicide and pesticide use may have caused populations to decline. Current efforts should focus on managing existing populations of Mead's milkweed. Landowners can take an active role in managing tall grass and hay meadow prairies to encourage and protect this rare plant.
Current Threats To Mead's Milkweed
- Early haying Haying done early in the year, prior to seed maturation, prevents Mead's milkweed from setting its seeds and reproducing.
- Lack of fire The absence of fire allows plant litter to accumulate and woody species to invade prairie habitat. Fire reduces plant litter, releases nutrients into the soil, and warms the soil. Fire also suppresses the invasion of woody plants into prairies. If unchecked, woody plants can convert prairies into habitat unsuitable for the milkweed.
- Overgrazing Intensive grazing allows woody and non-native plant species to invade prairies and increases soil erosion.
Protection and Management: Steps Toward Recovery
- Manage prairies to promote natural vegetation Haying during September will allow Mead's milkweed and other plants to set seeds. Areas managed under an annual hay/burn/rest rotation will support the largest diversity of plant species. Do not apply herbicide to actively growing Mead's milkweed. Do not harm or kill bumblebees found on site with Mead's milkweed.
- Periodically burn prairies to prevent the invasion of exotic and woody vegetation. Burn just prior to or right at spring greenup (typically early to mid April) and try to vary the burn dates each time. The later the spring burn, the greater the native prairie cover. Some woody species may have to be cut down and removed. Your local Natural Resources Conservation Service office or Missouri Department of Conservation Field Agent should be contacted prior to burning.
- Avoid grazing in pastures and fields where Mead's milkweed occurs. Rotate pastures to avoid overgrazing and use fire or haying to reduce levels of exotic vegetation.
Missouri and federal law prohibits the exportation, transportation, or sale plants on the State or Federal lists.
For more information on Mead's milkweed, or to report sightings of this species, contact:
Endangered Species Coordinator or Natural History Division Botanist Missouri Department of Conservation Natural History Division P.O. Box 180 Jefferson City, MO 65102 573/751-4115
For more information on pasture improvement programs or for additional information about Mead's milkweed management, contact:
Your local Natural Resources Conservation Service Office.
