great blue lobelia

(Lobelia siphilitica)

great blue lobelia (var. siphilitica)
Photo by Alfredo Colon

Great blue lobelia is an herbaceous perennial in the bellflower (Campanulaceae) family. It is native to the United States and southern Canada from Nova Scotia to South Carolina, west to Manitoba, eastern Colorado, and Louisiana. It is common in Minnesota.

Great blue lobelia is found in wet to moist habitats, including meadows, swamps, fens, and bottomland forests, at the edges of lakes and ponds, on streambanks and riverbanks, and on roadsides. It grows under partial shade to full sun in wet to moist, fertile, loamy soil.

Great blue lobelia is a popular garden plant. It is easy to grow and is tolerant of a variety of soils and conditions.


Great blue lobelia is a poisonous plant. All parts of the plant are toxic if eaten. Symptoms of poisoning include nausea, vomiting, diarrhea, salivation, exhaustion and weakness, dilation of pupils, convulsions, and coma.


Great blue lobelia is a 12 to 48 tall, erect or strongly ascending, perennial forb that rises on a single stem from a taproot.

The stem is erect, unbranched, and hairless or sparsely hairy.

The leaves are alternate, lance-shaped to elliptical, 2 to 6 inches (5-15 cm) long, and 0.5 to 1.5 inches (1.2-3.8 cm) wide. They are dark green in color and have a slightly toothed margin.

The inflorescence is an unbranched, spike-like cluster of 6 to 60 showy blue flowers at the end of the stem.

Each flower is to 1¼ long and about ½ wide. The corolla is tube shaped with a long, three-lobed lower lip and a short, two-lobed upper lip. The lower lobe is sometimes striped.

The fruit is a capsule with many small seeds.


Distribution Map



2, 3, 4, 5, 7, 24, 28, 29, 30.

  Kingdom Plantae (green algae and land plants)  
  Subkingdom Viridiplantae (green plants)  
  Infrakingdom Streptophyta (land plants and green algae)  
  Superdivision Embryophyta (land plants)  
  Division Tracheophyta (vascular plants)  
  Subdivision Spermatophytina (seed plants)  
  Class Magnoliopsida (flowering plants)  
  Superorder Asteranae  


Asterales (sunflowers, bellflowers, fanflowers, and allies)  


Campanulaceae (bellflower)  
  Subfamily Lobelioideae (lobelia)  


Lobelia (lobelias)  
  Section Lobelia (typical lobelias)  

Subordinate Taxa


great blue lobelia (Lobelia siphilitica var. ludoviciana)

great blue lobelia (Lobelia siphilitica var. siphilitica)






Common Names


blue cardinal-flower

blue lobelia

great blue lobelia

great lobelia











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  Great Blue Lobelia (Lobelia siphilitica)
Andree Reno Sanborn
  Great Blue Lobelia (Lobelia siphilitica)  

S1 in Vermont!




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Other Videos
  The Great Blue Lobelia (Lobelia siphilitica)

Published on Sep 2, 2012

The Great Blue Lobelia (Lobelia siphilitica)

  Great Blue Lobelia
Karl Foord

Published on Sep 29, 2013

No description available.






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