General Plant Information (Edit)
Plant Habit: Herb/Forb
Life cycle: Perennial
Sun Requirements: Full Sun
Full Sun to Partial Shade
Partial or Dappled Shade
Minimum cold hardiness: Zone 4a -34.4 °C (-30 °F) to -31.7 °C (-25 °F)
Maximum recommended zone: Zone 9b
Plant Height: 36 - 72 inches
Plant Spread: 24 - 48 inches
Flowers: Showy
Flower Color: Purple
Bloom Size: Under 1"
Flower Time: Summer
Late summer or early fall
Underground structures: Rhizome
Uses: Will Naturalize
Wildlife Attractant: Bees
Propagation: Seeds: Stratify seeds: 3 months at 40 degrees

Common names
  • Giant Ironweed
  • Tall Ironweed
Botanical names
  • Accepted: Vernonia gigantea
  • Synonym: Vernonia altissima

Photo Gallery
Location: Columbus, Ohio USA, Zone 6b
Date: 2023-08-24
Location: Indiana  Zone 5
Date: August
Location: My garden
Date: 2020-02-24
Location: Lilburn, GA
Date: 2022-10-10
Location: Indiana  Zone 5
Date: October
Location: Indiana  Zone 5
Date: August
close up
Location: Indiana  Zone 5
Date: 2010-09-24
dried seed still on plant
Location: Tennessee
courtesy Sunlight Gardens,

Photo courtesy of Annie's Annuals and Perennials
Location: Tyler Arboretum near Media, Pennsylvania
Date: 2012-07-25
a group near the parking lot
Location: Tyler Arboretum near Media, Pennsylvania
Date: 2012-07-25
Tiger Swallowtail on flowers
Location: My garden in Kalama, Wa. Zone 8
  • Uploaded by Joy
Photo by SongofJoy
Location: Tennessee
Date: 2012-03-19
young plant
Location: Tyler Arboretum near Media, Pennsylvania
Date: 2012-07-25
close-up of flowers and foliage
  • Posted by gardengus (Indiana Zone 5b) on Aug 28, 2014 1:01 PM concerning plant:
    This beautiful wildflower grows too tall for the place it has chosen, so I cut it in half around July 1st to keep it shorter. It still blooms, and at the same time as the uncut ones, just shorter.
  • Posted by ILPARW (southeast Pennsylvania - Zone 6b) on Mar 1, 2018 7:52 PM concerning plant:
    I really call this species the Tall Ironweed (Vernonia altissima) but I am sure Giant is also fine. It gets taller than the other species of up to 10 feet, though often 5 to 8 feet high. The leaves grow 4 to 12 inches long by up to 2.5 inches wide and can be smooth or slightly hairy beneath. Stems are smooth or slightly hairy also. It bears larger flower clusters of 6 to 16 inches in diameter. It grows in moist or wet soils from New York through southern Michigan through Illinois into Missouri and southward deep into the South from there. (Prairie Nursery in Westfield, Wisconsin says it is the showiest of the Ironweeds with pink-purple flowers held like torches atop the tall flower stalks, which butterflies can't resist. It makes a great back-of-the-border perennial, as well as a focal point in a wet meadow.) It is sold by some native plant nurseries.
  • Posted by SongofJoy (Clarksville, TN - Zone 6b) on Jan 15, 2012 2:38 PM concerning plant:
    If you want a tall perennial with rich reddish-purple flowers, Ironweed cannot be beaten. Ironweed is a common wildflower of moist fields and roadsides. Flower clusters are present from July to frost and can attain spreads of over 12 inches. Maturing from the inside out, flowers start out deep, dark reddish-purple and become light purple with contrasting white anthers that look like bits of snow on the flowers. The flowers are excellent as fresh-cut flowers. Because of its height (4 to 7 feet), it would be best at the rear of the garden or in natural areas. Ironweed is very attractive growing with Goldenrod, Joe Pye Weed, Wild Ageratum, Seashore Mallow, and Sunflowers. It needs full sun or partial shade and moisture.
Plant Events from our members
MrsBinWY On January 2, 2016 Seeds sown
On 1-2-2016, sowed 9 seeds from kchd in the 2015 SSS.
» Post your own event for this plant

« Add a new plant to the database

« The Plants Database Front Page

Today's site banner is by IrisLilli and is called "Purple Crocus Mix"

This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.