Vernonia lettermannii

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

Image Credits:

• Image 1 (blooms) Eric Hunt, CC BY-SA 4.0 <https://creativecommons.org/licenses/by-sa/4.0>, via Wikimedia Commons
• Image 2 (closeup) Krzysztof Ziarnek, Kenraiz, CC BY-SA 4.0 <https://creativecommons.org/licenses/by-sa/4.0>, via Wikimedia Commons
• Image 3 (form) Daderot, Public domain, via Wikimedia Commons