Ironweed Overview

Description On a bright late summer day, the purple flowers of ironweed glow. Ironweeds can take their place in sunny moist beds and borders, rain gardens, and beside ponds and streams. In limited space, cut the stems by half in early summer to control height. They are magnets for butterflies.
Genus Name Vernonia noveboracensis
Common Name Ironweed
Plant Type Perennial
Light Sun
Height 1 to 3 feet
Width 2 to 3 feet
Flower Color Purple
Season Features Colorful Fall Foliage, Fall Bloom, Summer Bloom
Special Features Attracts Birds, Cut Flowers, Low Maintenance
Zones 4, 5, 6, 7, 8
Propagation Division, Seed
Problem Solvers Drought Tolerant

Late Summer Star

Standing 4 to 6 feet tall at maturity, ironweed boasts a big garden presence when it begins blooming in late summer. That's because clusters of bright purple flowers decorate its tall stems for 6 weeks or more at the end of the growing season. Ironweed received its common name from its ironlike qualities: tough stems, tenacious growing habit, and flowers that give way to seed clusters the color of rust.

Pollinator Favorite

Ironweed provides nectar loved by pollinators: long-tongue bees, flies, skippers, and butterflies such as monarchs, swallowtails, and American painted ladies. It also provides a food source for caterpillar moths.

Create an oasis for these vital members of our ecosystem by planting ironweed alongside other pollinator plants: goldenrod, giant hyssop, prairie blazing star, smooth blue aster, and Culver's root, for example. In addition to planting for pollinators, you can enhance your backyard habitat by eliminating the use of pesticides. Control weeds through mechanical removal, soil cultivation, and thick layers of mulch that choke unwanted plants.

How to Grow Ironweed

Low-maintenance ironweed grows best with full sun and rich, moist almost acidic soil . Sunny, moist beds and borders, rain gardens, low areas, and stream banks suit it well. This perennial also thrives in casual cottage gardens, native prairie gardens, meadows, and other naturalized areas. Ironweed's bitter foliage makes it undesirable to most grazing animals, so it is considered a weed in pasture plantings.

Ironweed spreads readily through self-seeding. Limit its spread by snipping off flower heads before the seeds develop. Reduce the overall height of mature plants in late spring by cutting young stems back almost to the ground.

Plant Ironweed With:

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