Spiked lobelia is a single-stalked perennial with white or pale blue flowers all along the top portion of the stem. It is most common in sunny or grassy habitats like prairies, old fields, forest openings, and glades.
The flowers are in spikelike racemes along the top portion of stem; they are about ½ inch wide, with a 2-divided upper lip and a 3-divided lower lip, pale blue to dull white; subtended by a bractlike, linear leaflet. The flowers are smaller and paler than those of our other, more showy lobelias.
Blooms May–August.
The leaves are alternate, spaced apart, toothed, lance-shaped, to 3 inches long, and sessile (stalkless). The leaf bases continue downward past the attachment point, forming a pair of wings of green tissue along the stem.
Similar species: Missouri has five species of Lobelia, but only four are common:
- Indian tobacco, or inflated lobelia (L. inflata), is most similar to spiked lobelia, but its stems usually branch above the midpoint (while spiked lobelia's stems are usually unbranched, with only occasional branching near the base), and its fruit capsules become greatly inflated as the seeds ripen (while spiked lobelia's capsules are not inflated). It's an aggressive, somewhat weedy plant often found in disturbed areas. Also, Indian tobacco's flower stems are moderately to densely hairy (while spiked lobelia's are usually smooth or only sparsely hairy).
- Blue cardinal flower, or great blue lobelia (L. siphilitica), has violet, blue, or lavender flowers.
- Cardinal flower (L. cardinalis) has bright red flowers.
Height: to 3 feet.
Scattered statewide.
Habitat and Conservation
Occurs in open woods, prairies, glades, ledges and tops of bluffs, banks of streams and rivers, fens, pastures, old fields, railroads, roadsides, and open, disturbed areas.
Compared to cardinal flower and blue cardinal flower, spiked lobelia tolerates drier habitats.
Status
Native Missouri wildflower.
Human Connections
This plant is a good candidate for a sunny wildflower garden with rich to rocky soils.
Some species of lobelias possess chemicals similar to nicotine and have been used to make antismoking medications. Lobelias have been used historically for a variety of medicinal purposes. The sap of lobelias is toxic.
Ecosystem Connections
Several types of bees, butterflies, and skippers are attracted to the flowers.
The toxic latex in the sap prevents this plant from being consumed by many small mammals.
