Lobelia siphilitica (Great Blue Lobelia)

Native to eastern North America, this clump-forming herbaceous perennial grows in moist habitats. Stiff, leafy stems carry lance-shaped leaves with finely toothed edges. Dense terminal clusters bear blue, two-lipped flowers, with three prominent lower lobes and two smaller upper lobes. Blooming generally extends from midsummer into early autumn. Bumblebees and other long-tongued bees visit the flowers for nectar and pollen. All parts are poisonous if eaten. Photographed in Florida.