ExplorePlants

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.

KingdomPlantaePhylumTracheophytaClassMagnoliopsidaOrderAsteralesFamilyAsteraceaeGenusVernonia
Tall Ironweed
Tall Ironweed

Category

Plants

Rarity

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

Ability

Structural Resilience

Possesses remarkably tough, fibrous stems that resist breaking or bending, allowing the plant to stand tall through severe storms.

Ability

Chemical Deterrent

Synthesizes bitter sesquiterpene lactones that deter mammalian herbivores like deer and cattle from feeding on its foliage.

Ability

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

mutualism

Monarch Butterfly

Danaus plexippus

Provides rich late-season nectar to migrating butterflies, aiding their long journey south.

eaten by

Ironweed Borer Moth

Papaipema cerussata

The larvae of this moth bore into and feed on the internal stem tissue of the plant.

mutualism

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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