
Tall Ironweed
vernonia gigantea
Tall Ironweed is a majestic, robust perennial wildflower native to the eastern and central regions of North America. Renowned for its towering height and intense, deep-purple blooms, this plant is a striking late-summer centerpiece in natural landscapes. Its tough, rigid stems allow it to stand upright despite heavy winds and rain, earning it the rugged name 'Ironweed'. Because of its late blooming season, it provides a crucial nectar source for native bees, butterflies, and other pollinators when many other floral resources have begun to fade. While pasture owners often view it as an aggressive weed due to its unpalatability to livestock, it is highly valued in native restoration projects and wildflower gardens for its ecological benefits and bold aesthetic appeal. If you want to identify Tall Ironweed in the wild, use the Snappit app.
Habitat: Found in moist soils, wet meadows, low-lying fields, pastures, and along roadsides or forest margins.
Appearance
Tall Ironweed typically reaches heights of 100 to 300 centimeters, characterized by stout, coarse green to purplish stems that are mostly unbranched. Its leaves are lanceolate, finely serrated along the margins, and can grow up to 25 centimeters long, arranged alternately along the stem. The plant is crowned by loose, flat-topped clusters of numerous small, intense violet-magenta composite flower heads, which lack ray florets and consist entirely of tubular disc florets. After flowering, the seed heads mature into rusty-brown, fuzzy clusters that persist into the colder months.

Category
PlantsRarity
Common
Danger
1/5 ยท Very low
Snaps
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Interesting facts
Cattle avoid eating Tall Ironweed due to its bitter taste, allowing it to easily multiply and dominate overgrazed pasturelands.
The common name 'Ironweed' comes from the extremely tough, fibrous stems that remain standing long after the plant dies back in the winter.
The genus name Vernonia honors William Vernon, an English botanist who collected plant specimens in Maryland during the late 1600s.
Special abilities
Structural Resilience
Possesses remarkably tough, fibrous stems that resist breaking or bending, allowing the plant to stand tall through severe storms.
Chemical Deterrent
Synthesizes bitter sesquiterpene lactones that deter mammalian herbivores like deer and cattle from feeding on its foliage.
Late-Season Nectar Source
Produces highly concentrated nectar late in the season, acting as an essential energy source for migrating Monarchs and native bees.
Measurements & details
- Length
- 100-300 cm
- Lifespan
- 3-10 years
Diet & Feeding
As a photosynthetic plant, Tall Ironweed synthesizes its own sugars from sunlight, water, and carbon dioxide, while drawing minerals from the soil.
Primary Foods
- Sunlight
- Water
- Carbon dioxide
- Soil nutrients
Ecological connections

Monarch Butterfly
Danaus plexippus
Provides rich late-season nectar to migrating butterflies, aiding their long journey south.
Ironweed Borer Moth
Papaipema cerussata
The larvae of this moth bore into and feed on the internal stem tissue of the plant.
Long-horned Bee
Melissodes dentiventris
A specialized native bee that frequently visits the flowers to collect pollen and nectar.
Traits
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Also known as
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Safety
Danger
1/5 ยท Very low
No special safety notes yet.
Frequently Asked Questions
How to identify Tall Ironweed?
The easiest way to identify Tall Ironweed is to use the Snappit nature identifier app.
How long is Tall Ironweed?
100-300 cm
How long does Tall Ironweed live?
3-10 years
What does Tall Ironweed eat?
As a photosynthetic plant, Tall Ironweed synthesizes its own sugars from sunlight, water, and carbon dioxide, while drawing minerals from the soil.
Where is Tall Ironweed usually found?
Found in moist soils, wet meadows, low-lying fields, pastures, and along roadsides or forest margins.
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Where to spot

Arkansas, US
Marked Tree Lock and Siphons
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Illinois, US
Gompers Park
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Illinois, US
Eugene Field Park
You might spot Illinois Bundleflower, Wild Bergamot, and Cup Plant.
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