Lobelia siphilitica 

Local toxin that harms cows, horses, and other domestic livestock. The source of hay fever.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. The tubed portion of the flower is often striped. Great lobelia flowers have 5 petals; the 3 lower petals are fused, and the 2 upper petals are usually curled back. A curved style pokes between the upper two petals. The lower center lobe is wider and has 2 small bumps near the throat that are typically lighter in coloration.Lobelia siphilitica offers a deep-hued counterpoint to the yellows of late summer. This colony-forming, short-lived perennial grows well in medium to wet soils, especially with a little shade. In its native range, Great Blue Lobelia can be found in wet prairies, soggy meadows, pond and creek edges, marshland borders, and other moist areas.

Lobelia

Great lobelia is a clump-forming perennial which features an elongated cluster of light to dark blue, tubular, 2-lipped flowers with the three lobes of the lower lip appearing more prominent than the two lobes of the upper lip. The flowers arise from the upper leaf axils forming a dense terminal raceme atop stiff, unbranched, leafy stalks typically rising 2-3' tall. Its flowers are larger than other lobelias and have stripes on the tube portion. Blooms from July to October.A North American native that is perfect for the late summer garden, Lobelia siphilitica (Great Blue Lobelia) is a popular, upright perennial which produces long-lasting spikes of bright blue flowers atop a finely-toothed, lance-shaped foliage from late summer to mid fall.

Quite an architectural plant which adds vertical interest to the landscape. The nectar and pollen of the flowers attract primarily hummingbirds, bumblebees and other long-tongued bees. Extremely hardy, low care, and fairly pest and disease-free, Great Blue Lobelia tends to be short-lived, although it may self-seed in ideal growing conditions (without becoming invasive).The native Great Blue Lobelia occurs throughout Illinois, except for a few counties in southern Illinois. It is occasional to locally common. Typical habitats include moist black soil prairies, soggy meadows near rivers, low areas along rivers and ponds, floodplain and bottomland woodlands, woodland borders, bottoms of sandstone canyons along streams, swamps, fens, gravelly seeps and springs, ditches, and moist areas of pastures. Great Blue Lobelia can be found in both disturbed areas and high quality habitats. (Source:www.illinoiswildflowers.info)