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Vernonia Species, Ironweed, Smooth Ironweed, Prairie Ironweed

Vernonia fasciculata

Family: Asteraceae (ass-ter-AY-see-ee) (Info)
Genus: Vernonia (ver-NON-ee-uh) (Info)
Species: fasciculata (fas-sik-yoo-LAH-tuh) (Info)
Synonym:Cacalia fasciculata
View this plant in a garden



Foliage Color:


Bloom Characteristics:

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

Water Requirements:

Average Water Needs; Water regularly; do not overwater

Where to Grow:

Grow outdoors year-round


36-48 in. (90-120 cm)


24-36 in. (60-90 cm)


USDA Zone 4a: to -34.4 C (-30 F)

USDA Zone 4b: to -31.6 C (-25 F)

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)

Sun Exposure:

Sun to Partial Shade



Bloom Color:

Magenta (Pink-Purple)

Bloom Time:

Late Summer/Early Fall



Other details:

Unknown - Tell us

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:

By dividing the rootball

From seed; direct sow outdoors in fall

From seed; winter sow in vented containers, coldframe or unheated greenhouse

From seed; stratify if sowing indoors

Seed Collecting:

Collect seedhead/pod when flowers fade; allow to dry

Allow pods to dry on plant; break open to collect seeds

Properly cleaned, seed can be successfully stored


This plant has been said to grow in the following regions:

Vincent, Alabama

Marion, Arkansas

Pensacola, Florida

Lula, Georgia

Carlinville, Illinois

Chicago, Illinois

Hinsdale, Illinois

Greenville, Indiana

Iowa City, Iowa

Pacific Junction, Iowa

Yale, Iowa

West Monroe, Louisiana

Crofton, Maryland

Saint Paul, Minnesota

Elizabeth City, North Carolina

Norman, Oklahoma

Oklahoma City, Oklahoma

Pocola, Oklahoma

Wilkes Barre, Pennsylvania

Sevierville, Tennessee

Austin, Texas

Fort Worth, Texas

Westfield, Wisconsin

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Gardeners' Notes:


On Sep 18, 2015, Chillybean from (Zone 5a) wrote:

This plant is native to the US plant and was found in the Tallgrass Prairies. They like moist, but not wet conditions; they have done well without any watering other than what the Lord provides. Unlike some Ironweeds, this will grow in part-shade conditions.

One thing that often happens with tall plants is they are prone to flop, either from height, winds or heavy rains. Of the two full summers we had this plant grow and thrive, they have stood tall among the "flops" of the Maximilian Sunflowers and Rough Blazingstars. We've seen many pollinators on this plant, but not a lot of them being large butterflies. The leaves get chewed on, but nothing has ever caused great damage.


On Aug 10, 2015, PaddyMnoN from Pittsburgh, PA wrote:

I have seen this plant flourish in a garden in central Illinois - very hot summers and cold winters. It is an amazing attractor of butterflies and hummingbirds - there is always something interesting going on when the flowers are open (end of July this year). The bugs and birds ignore all the other "butterfly attractors" in the garden and go straight for the ironweed.
However, unlike the height given on this site, the ironweed
I saw (established over a few years) grows at least 6 feet tall.


On Aug 9, 2015, Rickwebb from Downingtown, PA wrote:

Ironweeds are good looking, easy to grow, and low maintenance perennials that grow wild in meadows. Native nurseries, as Prairie Nursery in Westfield Wisconsin, sell this spcies native to eastern North America. Some may need some staking.


On Oct 10, 2010, cedar18 from Lula, GA (Zone 7b) wrote:

The plant bloomed well but was too far in the back of the border. So I dug it up to divide it -- and what a job! It was very well rooted after two years, and I had to saw the rootball apart. There was no other way to divide it.


On Sep 9, 2008, MN_Darren from Saint Paul, MN wrote:

I've had it for three years. Not only is it really beautiful, it's also very tough, maintaining attractive foliage until the frost. August is bloom time, and it must be deadheaded in order to prevent the airborn seeds launched from their 6-7 foot platforms from covering the neighborhood. It is native to this area, and not outrageous in its water demands. It is a very logical companion to tall perennials like Joe Pye Weed, which it compliments nicely, which has similar demands. The only negative I have seen is really a matter of taste--do you need a 6-7 foot-tall, late summer deep purple, asterlike plant with really nice foliage and reseeding?


On Jun 2, 2006, Gabrielle from (Zone 5a) wrote:

My information says this is hardy to zone 3.