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Great Blue Lobelia, Blue Cardinal Flower - Lobelia siphilitica


Family: Campanulaceae - Bellflower family Genus Common Name: Lobelia Native Status: NativeDicot Perennial Herb Leaves:Alternate Leaves:Simple
Lobelia siphilitica - Great Blue Lobelia, Blue Cardinal Flower. The species epithet is because at one time it was believed the plant was used by native Americans to treat syphilis. Ingestion of the root can cause vomiting. It should be considered poisonous.

While the flowers are usually blue, in rare cases they may be white.

Found in:
AL, AR, CO, CT, DC, DE, GA, IA, IL, IN, KS, KY, LA, MA, MD, ME, MI, MN, MO, MS, NC, ND, NE, NH, NJ, NY, OH, OK, PA, SC, SD, TN, TX, VA, VT, WI, WV, WY, GS

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Lobelia siphilitica

Distribution of Lobelia siphilitica in the United States and Canada:
Map unavailable.
Map courtesy of The Biota of North America Program.
Map color key

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Site: Walker County, Ga Date: 2009-August-26Photographer: Gerald C Williamson
Great Blue Lobelia has the 'normal' but interesting petal structure for lobelias, with two lips, the upper lip being split with two lobes, and the lower lip having three lobes. The stamens form a tube around the style.
Lobelia siphilitica

Site: Walker County, Ga Date: 2009-October-19Photographer: Gerald C Williamson
Notice the stigma has emerged from the tube formed by the stamen in this mature Lobelia siphilitica specimen.
Lobelia siphilitica

Site: Walker County, GA Date: 2012-August-27Photographer: Gerald C Williamson
Nikon D7000
The older photos on this page were taken after sunset with long exposures, skewing the colors. This photo is closer to true.
Click on the photo for a larger image
Lobelia siphilitica

Site: Blue Ridge Parkway, Virginia Date: 2014-September-03Photographer: Gerald C Williamson
Nikon D7000
Roadside Great Blue Lobelia on the Blue Ridge Parkway in western Virginia.
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Lobelia siphilitica

Site: Walker County, Ga Date: 2014-September-10Photographer: Gerald C Williamson
Nikon D7000
While most publications report Great Blue Lobelia as 3 to 4 feet tall, clearly this one is taller, as I am 5 feet 9 inches tall. I might be standing in a small depression, but if so it is no more than 4 inches deep. This plant is at least 5 feet tall, I think more likely 6.
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Lobelia siphilitica

Site: Walker County, Ga Date: 2009-October-19Photographer: Gerald C Williamson
While a few blossoms remain along the plant, the Great Blue Lobelia seeds are developing by mid-October in north Georgia.
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Lobelia siphilitica

References used for identification and information:
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Lobelia siphilitica initially published on USWildflowers.com 2009-08-26; Updated 2018-12-09

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



Code Update 20230302