Iron Butterfly ironweed
Vernonia lettermannii 'Iron Butterfly'
GCA Plant of the Year 2026
USDA zones4 to 9
SunHandles full sun to partial sun
WaterHandles dry to moist soil
Sizeup to 3 feet tall
- Growth rate
- Moderate
- Habit
- Dense
- Bloom season
- Summer, autumn
- Soil types
- Sand, loam, clay, chalk
- Soil pH
- Acid, alkaline, neutral
Garden uses
Attracts
Notes
'Iron Butterfly' ironweed (Vernonia lettermannii 'Iron Butterfly') is a perennial for borders, cottage gardens, pollinator gardens, and rain gardens. It is hardy to USDA zone 4, or down to -30°F (-34°C). This plant likes full or part sun and dry to moist soil of most types. It forms a dense clump up to 36 inches tall and tolerates dry spells. Bees, butterflies, hummingbirds, and birds visit the blooms. Deer and rabbits tend to browse other plants first.
Pairs well with Purple Coneflower coneflower, False indigo, Little bluestem, and Indian grass.