Lobelia siphilitica L.
Great Blue Lobelia
Campanulaceae (Bellflower Family)
USDA Symbol: losi
This showy perennial is usually unbranched but may exhibit some branching. The erect, 2-3 ft., stems produce lavender-blue, tubular flowers crowded together on the upper stem. Showy, bright blue flowers are in the axils of leafy bracts and form an elongated cluster on a leafy stem. Each flower is split into two lips - the upper lip has two segments and the lower lip has three.
This blue counterpart of the Cardinal Flower (Lobelia cardinalis) is a most desirable plant for woodland gardens especially since it blooms bright blue in late summer. The unfortunate species name, siphilitica, is based on the fact that it was a supposed cure for syphilis.
From the Image Gallery
Bloom InformationBloom Color: Blue
Bloom Time: Jul , Aug , Sep , Oct
DistributionUSA: 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
Canada: NB , NS , ON
Native Distribution: CT to extreme s.e. ND & Goshen Co., WY, s. to GA uplands, TX & CO
Native Habitat: Open, wet woods; stream banks; marshes; meadows
Growing ConditionsLight Requirement: Sun , Part Shade , Shade
Soil Moisture: Moist , Wet
Drought Tolerance: Low
Soil Description: Clay, Loam, Sand
Conditions Comments: Not at all drought tolerant, keep soil moist, watering if necessary in average soil conditions.
BenefitWarning: POISONOUS PARTS: All parts. Toxic only if eaten in large quantities. Symptoms include nausea, vomiting, diarrhea, salivation, exhaustion and weakness, dilation of pupils, convulsions, and coma. Toxic Principle: Alkaloids lobelamine, lobeline, and others, plus a volatile oil. (Poisonous Plants of N.C.)
Conspicuous Flowers: yes
Attracts: Birds , Hummingbirds
Value to Beneficial InsectsSpecial Value to Native Bees
Special Value to Bumble Bees
Supports Conservation Biological Control
This information was provided by the Pollinator Program at The Xerces Society for Invertebrate Conservation.
PropagationDescription: To propagate, divide clumps in the spring or scatch stratified seed lightly onto the soil surface.
Seed Collection: Approximate collection date in northern U.S.: Mid Sep. to Nov.
Seed Treatment: Moist stratification for 2 months at 40 degrees.
Commercially Avail: yes
Find Seed or Plants
Find seed sources for this species at the Native Seed Network.
Mr. Smarty Plants says
Native plants to stop pond bank erosion
June 04, 2008
I recently purchased a home with a small pond in which a nearby stream daylights. The former owner placed large field stone around the pond and the small stream; however, the area around the pond and...
view the full question and answer
Native wildflowers for Northern Indiana
May 08, 2007
I had the wonderful opportunity to visit the Lady Bird Johnson Wildflower Center on Saturday April 21. What a beautiful place. I thoroughly enjoyed my visit. I was wondering how I could find out w...
view the full question and answer
National Wetland Indicator Status
From the National Organizations DirectoryAccording to the species list provided by Affiliate Organizations, this plant is on display at the following locations:
Native Plant Center at Westchester Community College, The - Valhalla, NY
Delaware Nature Society - Hockessin, DE
Native Seed Network - Corvallis, OR
Mt. Cuba Center - Hockessin, DE
BibliographyBibref 928 - 100 easy-to-grow native plants for Canadian gardens (2005) Johnson, L.; A. Leyerle
Bibref 1620 - Gardening with Native Plants of the South (Reprint Edition) (2009) Wasowski, S. with A. Wasowski
Bibref 946 - Gardening with Prairie Plants: How to Create Beautiful Native Landscapes (2002) Wasowski, Sally
Bibref 1294 - The Midwestern Native Garden: Native Alternatives to Nonnative Flowers and Plants An Illustrated Guide (2011) Adelman, Charlotte and Schwartz, Bernard L.
Search More Titles in Bibliography
Additional resourcesUSDA: Find Lobelia siphilitica in USDA Plants
FNA: Find Lobelia siphilitica in the Flora of North America (if available)
Google: Search Google for Lobelia siphilitica
MetadataRecord Modified: 2022-10-28
Research By: TWC Staff