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  • Vernonia lettermannii (threadleaf ironweed) flowers
  • Vernonia lettermannii (threadleaf ironweed) flowers
  • Vernonia lettermannii (threadleaf ironweed) form
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Vernonia lettermannii (threadleaf ironweed) flowers
Vernonia lettermannii (threadleaf ironweed) flowers
Vernonia lettermannii (threadleaf ironweed) form

threadleaf ironweed

Vernonia lettermannii | threadleaf ironweed

Ironweed are tall US natives that look quite similar to each other. All bloom late in the season; purple flowers are much loved by pollinators, especially butterflies.

Threadleaf ironweed is a compact clump-forming perennial with finely textured narrow leaves. Picture a small, rounded Amsonia hubrichtii with purple fall flowers. It tolerates hot, dry, rocky soil just as well as moist soil.

Zones: 4 to 9
Family: Asteraceae
Type: Perennial
Height: 24 to 36 in.
Spread: 24 to 36 in.
Exposure: Full Sun
Soil Conditions: Dry, average, moist
Bloom Time: August to September
Bloom Color: bright purple-violet
Native Range: Arkansas and Oklahoma

Special Characteristics
  • Pollinator favorite
  • Little to no care required (once established)
  • Architectural
image credits

Image 1 (blooms) Eric Hunt, CC BY-SA 4.0, via Wikimedia Commons
Image 2 (closeup) Krzysztof Ziarnek, Kenraiz, CC BY-SA 4.0, via Wikimedia Commons
Image 3 (form) Daderot, Public domain, via Wikimedia Commons

Vernonia lettermannii (threadleaf ironweed) flowers
Vernonia lettermannii (threadleaf ironweed) flowers
Vernonia lettermannii (threadleaf ironweed) form

See all in this genus