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Prairie ironweed

Vernonia fasciculata

A tall, clump-forming North American prairie perennial topped in late summer by broad, flat clusters of intense red-purple flowers. Native to the moist tallgrass prairies, wet meadows, and streambanks of the central United States and prairie Canada, it stands 3 to 6 feet on stiff, unbranched stems and demands full sun with consistently moist soil. Its late-season nectar makes it an outstanding pollinator plant - a fueling stop for monarchs heading south and a magnet for native bees and butterflies when little else is blooming.

Native: 14 US states + 1 CA province

Climate fit: moderate (63/100)

Pollinator

Structure

Light

Full sun

Water

Consistent moisture

Mature size

3-6 ft tall · 24" apart

Hardy in zones

3a-7b

brutally cold to cold winters

Native in Illinois

Yes

Related products

Cold hardiness

These values are location-based: this location's current hardiness is the baseline, and the 2050 value is a projected future climate for this same location.

Now

Zone 6b

Plotwright

USDA Zone 6b

-5°F to 0°F

Well-suited

2050

2100

Zone 7a

Plotwright

0°F to 5°F

Well-suited

In plain terms: This location has cold winters. Its winters are projected to keep warming through 2050.

✓

Well-suited today and still thriving in 2050.

Heat tolerance

Heat tolerance values are location-based too: heat days today are observed at this site, and the 2050 value projects this same location under a future climate.

Loading AHS heat-zone data for this location...

Where this plant fits

Suitable across 35 ecoregions - 27 climate-resilient through 2070 · 5 suited today · 3 newly possible by 2070. Best matches first.

Appalachian mixed mesophytic forests

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Appalachian-Blue Ridge forests

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Arizona Mountains forests

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Atlantic coastal pine barrens

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Blue Mountains forests

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Central Tallgrass prairie

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Central-Southern Cascades Forests

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Chilean Matorral

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Colorado Rockies forests

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Cross-Timbers savanna-woodland

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Similar plants

Browse lateral options with similar roles, light needs, size, or native-range overlap; these are not filtered for a better climate fit.

Eupatorium perfoliatum

Boneset

A large, hairy, clump-forming North American native perennial of wet meadows, low woods, stream banks, and prairies. Its most distinctive feature is the perfoliate foliage - pairs of wrinkled, opposite, lance-shaped leaves whose bases fuse around the hairy stem, so the stem appears to pass through the leaf. From July to September, flat-topped clusters of small, fluffy white flowers feed a wide range of bees, butterflies, and other pollinators, while all parts of the plant are toxic and bitter.

Perennial

Full sun / Part sun / Part shade

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Perennial

Full sun / Part sun / Part shade

A tall native perennial wildflower of moist meadows and woodland edges across eastern North America, producing large domed clusters of vanilla-scented pink-purple flowers in late summer - among the most reliable late-season nectar sources for monarchs, swallowtails, skippers, and native bees. Formerly classified as Eupatorium purpureum.

A tall, clump-forming native legume of eastern North America grown for showy mid- to late-summer clusters of gold-yellow flowers accented by dark, curving anthers. The pinnately compound leaves carry a club-shaped gland on the petiole, and the long-lived plants reach 4 to 6 feet. Bumblebees work the pollen-only flowers, hummingbirds visit, and the seeds feed birds including bobwhites.

Perennial

Full sun / Part shade

A long-lived native perennial of central and eastern US woodland borders and prairie meadows with deep blue pea-shaped flowers in late spring, blue-green leguminous foliage, attractive black seed pods for winter interest, and a nitrogen-fixing root system (Fabaceae). Larval host for 6 documented butterfly species per NC State (orange sulphur, clouded sulphur, frosted elfin, eastern tailed-blue, hoary edge, wild indigo duskywing) - among the highest Lep-host-count perennials in the eastern flora.

Perennial

Full sun / Part shade

Educator packet

Plant packet

Prairie ironweed educator packet

A tall, clump-forming North American prairie perennial topped in late summer by broad, flat clusters of intense red-purple flowers. Native to the moist tallgrass prairies, wet meadows, and streambanks of the central United States and prairie Canada, it stands 3 to 6 feet on stiff, unbranched stems and demands full sun with consistently moist soil. Its late-season nectar makes it an outstanding pollinator plant - a fueling stop for monarchs heading south and a magnet for native bees and butterflies when little else is blooming.

Scientific name

Vernonia fasciculata

Plant type

perennial

Hardiness

3a-7b

Light

full-sun

Moisture

consistent

Spacing

24 inches

Classroom prompts

- Which plant traits are observations, and which are care recommendations?

- How would this plant fit change if the garden location moved warmer, colder, wetter, or drier?

- Which source-backed facts would you cite in a lesson handout?

Use the Sources & citations section below for page citation styles and the field-level source list.

Sources & citations

Cite this page

For lesson plans, articles, or research that uses this page. Use the source cards below to explore the references that informed this record.

Plotwright. (2026, May 17). Prairie ironweed (Vernonia fasciculata). Retrieved 2026, August 20, from https://plotwright.com/plants/vernonia-fasciculata

Sources used for this record

This record is compiled from the sources below.

GBIF

Botanical research database

Open source

Source guide

Wikipedia (ecoregion articles)

Botanical research database

Open source

Source guide

Wikimedia Commons

Photo · Public domain