Vernonia Species, Giant Ironweed, Tall Ironweed

Vernonia gigantea

Family: Asteraceae (ass-ter-AY-see-ee) (Info)
Genus: Vernonia (ver-NON-ee-uh) (Info)
Species: gigantea (jy-GAN-tee-uh) (Info)
Synonym:Chrysocoma gigantea
Synonym:Chrysocoma praealta
Synonym:Vernonia oligantha
Synonym:Vernonia ovalifolia



Water Requirements:

Unknown - Tell us

Sun Exposure:

Sun to Partial Shade




This plant is resistant to deer

Foliage Color:

Unknown - Tell us


6-8 ft. (1.8-2.4 m)


12-15 in. (30-38 cm)


USDA Zone 5a: to -28.8 C (-20 F)

USDA Zone 5b: to -26.1 C (-15 F)

USDA Zone 6a: to -23.3 C (-10 F)

USDA Zone 6b: to -20.5 C (-5 F)

USDA Zone 7a: to -17.7 C (0 F)

USDA Zone 7b: to -14.9 C (5 F)

USDA Zone 8a: to -12.2 C (10 F)

USDA Zone 8b: to -9.4 C (15 F)

USDA Zone 9a: to -6.6 C (20 F)

Where to Grow:

Unknown - Tell us


Handling plant may cause skin irritation or allergic reaction

Bloom Color:

Magenta (pink-purple)

Fuchsia (red-purple)



Medium Purple

Bloom Characteristics:

This plant is attractive to bees, butterflies and/or birds

Bloom Size:

Unknown - Tell us

Bloom Time:

Mid Summer

Other details:

May be a noxious weed or invasive

Soil pH requirements:

5.6 to 6.0 (acidic)

6.1 to 6.5 (mildly acidic)

6.6 to 7.5 (neutral)

Patent Information:


Propagation Methods:

From seed; direct sow outdoors in fall

From seed; stratify if sowing indoors

Self-sows freely; deadhead if you do not want volunteer seedlings next season

Seed Collecting:

Allow seedheads to dry on plants; remove and collect seeds


This plant is said to grow outdoors in the following regions:

Auburn, Alabama

Hanceville, Alabama

Morrilton, Arkansas

Richmond, California

Sacramento, California

Wethersfield, Connecticut

Fort Lauderdale, Florida

Lake Wales, Florida

Mayo, Florida

Pensacola, Florida

Cornelia, Georgia

Demorest, Georgia

La Grange Park, Illinois

Minooka, Illinois

Barbourville, Kentucky

Melbourne, Kentucky

Salvisa, Kentucky

Allen Park, Michigan

Midland, Michigan

Saint Paul, Minnesota

Croton On Hudson, New York

Pomona, New York

Lake Toxaway, North Carolina

Bowling Green, Ohio

Columbus, Ohio

Fort Jennings, Ohio

Guysville, Ohio

Hamilton, Ohio

Carlisle, Pennsylvania

Lewisburg, Pennsylvania

Millersburg, Pennsylvania

Pennsburg, Pennsylvania

Clarksville, Tennessee

Collierville, Tennessee

Maryville, Tennessee

Arlington, Texas

Princeton, Texas

Santa Fe, Texas

Kalama, Washington

Spencer, West Virginia

show all

Gardeners' Notes:


On Jul 12, 2020, Bandita74 from Mount Ivy, NY wrote:

This plant is a favorite of all pollinators. Right now, my largest one is about 6 feet and already starting to make buds in my zone 6b garden. I added a few more this season just because its such a huge hit with all flying creatures. Its in a part sun area and still blooms well and of course its a native so what could be better than that?


On Sep 1, 2012, luciee from Hanceville, AL (Zone 7a) wrote:

I rate this one as lovely. It grows wild here but I could not get the seeds I collected to germinate. So I found a source of seed on-line and bought them They came up and bloomed very nicely. Luciee {;^)


On Jul 30, 2012, Clary from Lewisburg, PA (Zone 6b) wrote:

In its second year in the perennial garden this plant has formed a bushel-sized clump and has reached 9' tall. It is tied to a fence post, otherwise I'm sure it would not stand erect on its own, especially after the weight of rain on open flowers. The flowers are very numerous and blue-purple in color. Bees like them and I have seen some butterflies on the flowers as well (although they prefer the neighboring buddleias). Supposedly, goldfinches like ironweed seeds, and I hope that is true!


On Aug 29, 2009, mslehv from Columbus, OH (Zone 5b) wrote:

This is truly a massive plant with almost flourescent purple blooms. Unfortunately, the bloom period is limited to about three weeks. The "Ironweed" may refer to its roots - even a six inch first year plant had deep, thick, iron-like roots. In full sun, first year growth was over six feet and second year reached over nine feet (see posted image).


On Jul 7, 2007, jostoich from Sacramento, CA (Zone 9a) wrote:

I love it. I've had it for several years in my backyard in Sacramento, CA. It hasn't become invasive for me and hasn't reseeded or spread at all. I have it planted in partial shade near a wooden post that a bird feeder hangs from. The color is vivid and birds have been visiting my yard this year. Perhaps this plant is attracting them, but I do have many other plants that also attract birds.


On Sep 9, 2005, Breezymeadow from Culpeper, VA (Zone 7a) wrote:

This lovely wildflower is just coming into its own this time of year (September). Indigenous here - the Piedmont area of VA - it enjoys both the sun & semi-shade of damp to marshy meadow areas. It's extreme height along with the deep royal purple blossoms can be seen from quite a distance.

While it may be considered a noxious weed in some areas, that doesn't seem to be the case around here, where it is rarely found in any sort of massive abundance


On Apr 5, 2004, JenniesWorld from Spencer, WV wrote:

This woody weed can get quite tall, often towering over the cattle in the pastures where it thrives. It seems to like moist areas, and even does well in semi-shade. The color intensity of the blooms are awesome, with rich shades of purples. Too bad it is a noxious weed! Some places you can be fined for letting it grow! Jennie