Vernonia gigantea

Common Names

Giant Ironweed, Tall Ironweed, Ironweed

Summary

Giant Ironweed (Vernonia gigantea) is a tall, herbaceous perennial native to the eastern United States, forming clumps via short rhizomes and bearing erect stems with lance-shaped leaves up to 12–25 cm long. It features dense heads of purple disk florets (no ray florets) that bloom from midsummer to fall, creating a striking vertical display attractive to butterflies and bees. It is hardy in USDA zones 5–8, thrives in full sun to partial shade, and prefers moist to wet soils, tolerating periodic flooding. It spreads by rhizomes to form clumps and can become aggressive, requiring management; propagation is by seed or division, and it suits back borders, native wildflower gardens, prairies, and butterfly habitats in landscape plantings.

Lifecycle

Perennial

Height

5-8 feet

Spread

36-72 inches

Hardiness Zones

Zones 5-8

Sunlight Requirements

Ideally Full Sun to Partial Shade.

Soil Type

Moist, well-drained soil, ideally loam, clay-loam, or sandy-loam textures

Soil Drainage

Moist to wet, well-drained soils.

Soil pH

5.5-7.0, slightly acidic to neutral

Bloom Color

Purple

Bloom Time

Summer to Fall

Foliage Color

Dark green to purplish-green to brown

Fall Foliage Color

Green

Leaf Lifecycle

Deciduous

Growth Rate

Fast

Seasons of Interest

Summer and Fall

Propagation Methods

Seeds, Cuttings, and Division

Attracts Wildlife

Attracts bees, Attracts butterflies, Attracts other pollinators, Attracts birds