Description: This native perennial plant
is 1-4' tall. It is erect and usually remains unbranched. The alternate leaves
are up to 5" long and 2" wide, lanceolate or ovate, with serrated margins, and
without petioles. The central stem terminates in a long and slender raceme of
blue-violet flowers. Each flower has 2 upper lobes and 3 lower lobes that flare
outward from a tubular corolla that is 1-1½" long. There is no
noticeable floral scent. The calyx is green and conspicuously hairy. The
blooming period occurs from late summer into fall, and lasts about 2 months.
Sometimes plants produce white flowers, and other color variations are
possible. The root system consists of a central taproot, from which occasional
basal offshoots are produced. The seeds are quite small, and are probably
distributed to some extent by wind or water.
Cultivation: The preference is wet to moist soil and
partial sun. Full sun is tolerated if the soil is consistently moist, and light
shade is also acceptable. The soil should be fertile and loamy. This plant
withstands occasional flooding, but becomes muddy and ragged-looking if it
receives too much abuse. The small seeds require light to
germinate.
Range & Habitat:
Great Blue Lobelia occurs throughout Illinois, except for a few counties in
southern Illinois (see
Distribution
Map). It is occasional to locally common. Typical habitats include moist
black soil prairies, moist meadows near rivers, floodplain forests, woodland
borders, swamps, fens, gravelly seeps and springs, lake borders, ditches, and
moist areas of pastures. This plant occurs in both disturbed areas and high
quality habitats.
Faunal
Associations: The flowers attract bumblebees primarily. Less common
visitors include hummingbirds, butterflies, and Halictid bees. The latter group
of bees collect pollen only and are non-pollinating. Most mammalian herbivores
don't eat this plant because the foliage contains several toxic alkaloids,
chief among them being lobeline and lobelanine. These toxic substances produce
symptoms that resemble nicotine poisoning. However, it has been reported that
deer occasionally eat this plant, perhaps enjoying greater immunity to these
toxic substances than other animals. The seeds are too small to be of much
value to birds.
Photographic
Location: The photographs were taken near a drainage ditch at Judge
Webber Park in Urbana, Illinois.
Comments: Great Blue Lobelia is a lovely plant and
produces some welcome diversity with its violet-blue flowers during late summer
or fall, when forbs with yellow flowers are typically dominant. Unfortunately,
its value to wildlife is rather limited.