Wildflowers of the United States

Tall Ironweed, Giant Ironweed, Ironweed - Vernonia gigantea

Genus Common Name: Ironweed

Native Status: Native

Dicot Perennial Herb

Vernonia gigantea - Tall Ironweed, Giant Ironweed, Ironweed. One or more species of Ironweed is found in 40 of the 50 states. Vernonia gigantea is one of the more widespread species, being found in 25 states. As the name implies, it can be a tall species, up to 10 feet. The purple flowers bloom in August and on into November.

Leave comments on Vernonia gigantea at this link.

Distribution of Vernonia gigantea in the United States and Canada:

Map courtesy of The Biota of North America Program.
Map color key
Search Our Database: Enter any portion of the Scientific, Common Name, or both.

Do a general Google search of the entire site:

#ad

Follow USWildflowers on Twitter

#ad

Site: Walker County, GA Date: 2009-October-03	Photographer: Gerald C. Williamson Nikon D60
Vernonia gigantea is a member of the Aster family (some call it the Composite Family; some call it the Sunflower family) with only disk florets. There are 13 to 30 florets per blossom. The similar New York Ironweed (Vernonia noveboracensis), which shares much of the eastern-most range with V. Gigantea, has more than 30 florets per bloom.

Site: Walker County, GA Date: 2009-October-03	Photographer: Gerald C Williamson Nikon D60

Click on the photo for a larger image
Site: Walker County, GA Date: 2010-October-09	Photographer: Gerald C Williamson Nikon D60
Ironweed catching morning rays along with frequent co-habitant Goldenrod in the background.
Click on the photo for a larger image
Site: Walker County, GA Date: 2010-August-15	Photographer: Gerald C Williamson Nikon D60
The features of involucre parts of many species are used as identifying characteristics. From one description of Vernonia gigantea: "Phyllaries 30–40+ in 4–5 series, glabrate, margins ciliolate, the outer lance-ovate, 1–2 mm, inner oblong, 3.5–5 mm, tips acute or rounded-apiculate." Near as I can translate, that describes these. (Description from Missouri Botanical Gardens.)
Click on the photo for a larger image
Site: Walker County, GA Date: 2010-August-14	Photographer: Gerald C Williamson Nikon D60

Click on the photo for a larger image
Site: Walker County, GA Date: 2010-August-15	Photographer: Gerald C Williamson Nikon D60
The stem of Tall Ironweed may be smooth, or may be covered with tiny hairs as shown in this photo.
Click on the photo for a larger image
Site: Walker County, GA Date: 2010-August-15	Photographer: Gerald C Williamson Nikon D60
Both the upper and lower surfaces of Vernonia gigantea are rough-feeling. The leaf edges are serrated. This plant may include some hybridization with V. flaccidifolia - Tennessee Ironweed - since it does not show the obvious hairs which would be typical of Tall Ironweed.
Click on the photo for a larger image
Site: Walker County, GA Date: 2010-October-09	Photographer: Gerald C Williamson Nikon D60 Tamron SP 90MM f/2.8 AF Macro
Bumblebee leg holding on to an Ironweed blossom on a cool, dewy morning.
Click on the photo for a larger image
Site: Walker County, GA Date: 2010-November-21	Photographer: Gerald C Williamson Nikon D60 Nikon Nikkor AF-S 18-55mm 4-5.6 VR ED 55 (82 equiv)
Ironweed may be as beautiful in the fall as in the summer. Here with a backdrop of Goldenrod.
Click on the photo for a larger image

#ad

Vernonia gigantea initially published on USWildflowers.com 2010-08-17; Updated 2015-06-24

Commercial / Cookie Notice

Looking for Wildflowers for a specific state? Check here:

All content except USDA Plants Database map Copyright Gerald C. Williamson 2024
Photographs Copyright owned by the named photographer

Code Update 20230302