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A Comprehensive Guide to Missouri Ironweed (Vernonia missurica)

Missouri Ironweed (Vernonia missurica) is a herbaceous perennial that is native to the mid-western and southeastern United States. This plant is a host to the American Lady butterfly (Vanessa virginiensis). Growing from 2 to 6.5 feet tall, this species grows in prairies, and has magenta flowers that bloom from July to September. This plant is hardy in zones 5-9.

Taxonomy and Naming of Missouri Ironweed (Vernonia missurica)

Herbarium specimen of Missouri ironweed (Vernonia missourica).
Herbarium Specimen — Vernonia missurica Raf. collected in United States of America by The New York Botanical Garden (licensed under CC BY 4.0).

Taxonomy

Missouri Ironweed (Vernonia missurica) was named and described by Constantine Rafinesque, a French botanist, in 1833. This species has kept the same name since and is a member of the Aster Family (Asteraceae).

Meaning of the Scientific and Common Names

Scientific Name

The genus name, Vernonia, is in honor of William Vernon, an English botanist. The species name, missurica, is a Latinized version of the original collection location.

Common Name and Alternative Names

The common name comes from the original collection location in Missouri. No other common names have been encountered in the literature.

Physical Description of Missouri Ironweed (Vernonia missurica)

Magenta-purple flowers of Missouri ironweed (Vernonia missurica).
Flowers of Missouri Ironweed (Vernonia missurica) — KatieLMiller, CC BY 4.0, via Wikimedia Commons

Description

  • Plant Type: This plant is a herbaceous perennial.
  • Height: This plant is 2 to 6.5 feet tall.
  • Stem: The stem is erect and hairy. This plant is rhizomatous (Midwest National Tech Center 1997).
  • Leaves: The leaves are alternate, simple, serrate, and lanceolate to elliptic in shape. The leaves are 2-8 inches in length and 0.7-2 inches in width.
  • Flower color: Magenta to purple (Missouri Botanical Garden), white – f. Swinkii (Steyermark 1957) or rose – f. carnea (Standley 1930)
  • Blooming period: This plant blooms from July to September.
  • Fruiting type and period: This plant has achenes that mature in the late summer to fall.

Range of Missouri Ironweed (Vernonia missurica) in the United States and Canada

Range map of Missouri ironweed (Vernonia missurica) in the United States and Canada.
Range Map Credit: Kartesz, J.T., The Biota of North America Program (BONAP). 2023.(website http://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 ironweed is native to the mid-west and southeastern United States and the province of Ontario in Canada. It is considered to be rare in the states of Kansas, Ohio, Oklahoma, and the province of Ontario.

Habitat

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

This species grows in prairies (Flora of North America), wet meadows and prairies (Faust 1972), successional areas (Rosen 2007), successional areas in floodplains (Gleason 1919), roadsides (Standley 1930 and Henry and Henry 1983), railroads (Faust 1972), fields (Thompson 1979 and Mohlenbrock 1968), bogs (Macroberts and Macroberts 1998 and Hawkins and Richards 1995), and disturbed areas (Dutton and Dale 1990).

Hosted Insects

American lady butterfly on white flower.
American Lady Butterfly (Vanessa virginiensis) — ALAN SCHMIERER, CC0, via Wikimedia Commons

This species is a host for the American Lady Butterfly (Vanessa virginiensis). The immaculate meloid (Epicauta immaculata) has also been noted as using this species as a food source (Selander and Mathieu 1969).

Other Supported Wildlife

Close-up of yellow flowers of canada goldenrod (Solidago canadensis) with a bee.
Flowers of Canada Goldenrod (Solidago canadensis) — AnRo0002, CC0, via Wikimedia Commons

This species is a nectar source to other butterflies, skippers, bees, and wasps during the growing season. Birds, such as goldfinch, like to eat the seeds in the fall.

Frequently Asked Questions about Missouri Ironweed (Vernonia missurica)

Does this plant have any ethnobotanical uses?

The Native American Ethobotanical Database states that this plant has been used for skin diseases, dyes, fibers, and foods.

How is this plant distinguished from other Ironweeds?

This species is similar to the giant ironweed (Vernonia gigantea), but is separated by the lack of scabrous leaves and resin glands (Weakley, et al 2022) and the pubescent leaf underside (Midwest National Tech Center 1997). Having greater than 30 florets in the flower separates it from western ironweed (Vernonia baldwinii) (Weakley, et al 2022). Generally there are more flowers towards the top of the plant (Gleason 1919).

Is this plant invasive?

This plant has been noted as being weedy (Jones 1982).

Is this plant deer resistant?

This plant has been noted as being deer resistant by the Missouri Botanical Garden. It is also rejected by livestock in pastures (Swink 1986), likely because of the presence of sesquiterpene lactones that give a bitter taste (Jones 1982).

Gardening with Missouri Ironweed (Vernonia missurica)

Add Missouri Ironweed to Your Garden

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Plant of Missouri ironweed (Vernonia missourica) in a field.
Missouri Ironweed (Vernonia missurica) — Mason Brock (Masebrock), Public domain, via Wikimedia Commons

Hardiness

This species is hardy in zones 5-9. 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 in places with full sun with medium to wet soils and can tolerate flooding.

References

  • Dutton, Bryan Eugene and Thomas R. Dale. 1990. The vascular flora of three wildlife refuges in Cameron Parish, Louisiana. Phytologia 68: 333-362.
  • Faust, W. Zack. 1972. A Biosystematic Study of the Interiores Species Group of the Genus Vernonia (Compositae). Brittonia 24: 363-378.
  • Gleason, H.A. 1919. Variability in Flower Number in Vernonia missurica Raf. The American Naturalist 53: 624-629.
  • Hawkins, T.K. and E.L. Richards. 1995. A Floristic Study of Two Bogs on Crowley’s Ridge in G
  • Henry, Robert D. and Scott A. Henry. 1983. New state records and other noteworthy collections for the Illinois vascular flora. Phytologia 52: 331-335.
  • Jones, S.B. 1982. The genera of Vernoniae (Compositae) in the southeastern United States. Journal of the Arnold Arboretum 63: 489-507.
  • Macroberts, Barbara R. and Michael H. Macroberts. 1998. Floristics of muck bogs in east central Texas. Phytologia 85: 61-73.
  • Midwest National Tech Center. 1997. Midwestern Wetland Flora: Field Office Guide to Plant Species. (Lincoln, NE: USDA Soil Conservation Service).
  • Mohlenbrock, Robert H. 1968. A Floristics Study of Bell Smith Springs, Pope County, Illinois. Transactions of the Illinois Academy of Science 61: 53-79.
  • 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.
  • Selander, Richard B. and Juan M. Matheiu. 1969. Ecology, Behavior, and Adult Anatomy of the Albida Group of the Genus Epicauta (Coleoptera, Meloidae). Illinois Biological Monographs 41:
  • Standley, Paul Carpenter. 1930. New forms and varieties of Indiana Plants. Rhodora 32: 32-34.
  • Steyermark, Julian A. 1957. White-flowered Form of Liatris and Vernonia. Rhodora 59: 23-24.
  • Swink, Floyd A. 1986. Wildflowers of the Chicago Area: Late Summer and Autumn. Field Museum of Natural History Bulletin 57: 11-18.
  • Thompson, Ralph L. 1979. Vascular Flora of Cedar Gap Lake and Environs, Webster and Wright Counties, Missouri. Sida 8: 71-89.
  • Weakley, A.S., and Southeastern Flora Team 2022. Flora of the Southeastern United States. University of North Carolina Herbarium, North Carolina Botanical Garden.
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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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