Western Ironweed (Baldwin's Ironweed)

Western ironweed flowerhead in bloom
Scientific Name
Vernonia baldwinii
Family
Asteraceae (daisies and sunflowers)
Description

Western, or Baldwin's ironweed is one of five species of ironweeds in Missouri. Ironweeds are tough, grayish-green, branching perennials known for their fluffy-looking clusters of reddish-purple florets. Western ironweed is the most common and widespread of Missouri's ironweeds.

Leaves are alternate, hairy, lance-shaped, sharply pointed at both ends, with short stems, to about 6 inches long. The undersurface is covered with more or less evenly distributed, relatively long, often bent or tangled hairs. The margins are usually finely toothed, less commonly coarsely toothed.

Flowerheads are numerous, rose-purple (occasionally white), with 17–34 florets per head. The involucral bracts (overlapping, scale-like structures at the base of the heads) are commonly short-tapered to a sharply pointed tip that is loosely ascending or curving, curling, or spreading back, usually with abundant minute, impressed resin glands on both sides of the noticeably keeled midvein. Blooms May–September.

Learn more about Missouri’s ironweeds on their group page.

Similar species: There are five Vernonia species in Missouri. The two most similar to western ironweed are tall ironweed (V. gigantea) and Missouri ironweed (V. missurica). The long-pointed, backward-curling bracts at the base of the flowerheads identify western ironweed; western ironweed also tends to grow in drier habitats, begins blooming earlier in the season, and, compared to tall and Missouri ironweeds, it is stouter and has wider leaves.

Keep in mind that when different species of ironweeds grow near each other, they often hybridize, producing offspring that resemble a blend of their parent species.

Size

Height: about 2–5 feet.

Where To Find
image of Western Ironweed Baldwin’s Ironweed distribution map

Scattered to common nearly statewide; less common in parts of northern Missouri and the Bootheel.

Occurs in upland prairies, glades, upland forests, sometimes on banks of streams and edges of ponds, also pastures, fencerows, old fields, railroads, roadsides, and other open, disturbed areas.

This is by far the most abundant ironweed species in Missouri.

Ironweeds are a familiar sight on roadsides and pastures. They often indicate overgrazing, as cattle apparently avoid eating them.

Native perennial wildflower.

Ironweeds were used medicinally by Native Americans, mostly as pain relievers.

Some species of ironweeds are being researched for possible use in modern medicines.

Ironweeds are generally unwelcome on pastures, where their bitterness makes them distasteful to cattle.

Although herbivorous mammals such as deer and rabbits apparently find the foliage distasteful, butterflies, bees, and other insects are attracted to the flowers.

Goldfinches and other seed-eating birds eat the seeds when they develop in late summer and fall.

Media Gallery
Western ironweed flowerhead in bloom
Western ironweed is one of five species of ironweeds in Missouri. All of them bear showy clusters of magenta or purple flowerheads at the branching tops of upright stalks.
Julianna Schroeder
1/9
Photo of western ironweed flower clusters and leaves
Ironweeds are tough, grayish-green, branching plants known for their fluffy-looking clusters of reddish-purple florets. They are a familiar sight on roadsides and pastures. Identify western ironweed by the bracts at the base of the flowerheads.
Karan A. Rawlins, University of Georgia, Bugwood.org
2/9
Western ironweed flower clusters in bloom
Western ironweed, like our other ironweeds, has multiple branches at the top of the stem; each branch is tipped with a magenta-pink flowerhead composed only of disc florets (and no petal-like ray florets).
Julianna Schroeder
3/9
Closeup of western ironweed flowers
Western ironweed is one of five species of ironweeds in Missouri. All of them bear showy clusters of magenta or purple flowerheads at the branching tops of upright stalks.
Julianna Schroeder
4/9
Western ironweed plant growing among several other plants
Western ironweed is by far the most abundant species of ironweed in Missouri. It usually lives in drier, more upland habitats than our other ironweeds.
Julianna Schroeder
5/9
Western ironweed flowerheads, side view, showing recurved involucral bracts
Identify western ironweed by its involucral bracts, which have pointed, angled or recurved tips, resin glands, and keeled midveins.
Julianna Schroeder
6/9
Closeup of undersurface of a western ironweed leaf
The undersurfaces of western ironweed leaves have more or less evenly distributed, relatively long, often bent or tangled hairs.
Julianna Schroeder
7/9
Western ironweed leaf with rather finely toothed margins
Western ironweed’s leaf margins are usually finely toothed, less commonly coarsely toothed.
Julianna Schroeder
8/9
Western ironweed leaf with rather coarsely toothed margins
Western ironweed’s leaf margins are usually finely toothed, less commonly coarsely toothed.
Julianna Schroeder
9/9
Western ironweed flowerhead in bloom
Photo of western ironweed flower clusters and leaves
Western ironweed flower clusters in bloom
Closeup of western ironweed flowers
Western ironweed plant growing among several other plants
Western ironweed flowerheads, side view, showing recurved involucral bracts
Closeup of undersurface of a western ironweed leaf
Western ironweed leaf with rather finely toothed margins
Western ironweed leaf with rather coarsely toothed margins
Similar Species
About Wildflowers, Grasses and Other Nonwoody Plants in Missouri
A very simple way of thinking about the green world is to divide the vascular plants into two groups: woody and nonwoody (or herbaceous). But this is an artificial division; many plant families include some species that are woody and some that are not. The diversity of nonwoody vascular plants is staggering! Think of all the ferns, grasses, sedges, lilies, peas, sunflowers, nightshades, milkweeds, mustards, mints, and mallows — weeds and wildflowers — and many more!