In the late summer and early fall, great blue lobelia adds unusual blue flowers to areas with full sun and moist soils. Plants are medium to large perennials that work well in meadows, near streams and ponds, and in pollinator gardens, butterfly gardens, native gardens, and rain gardens. This species is native to the Chicago region according to Swink and Wilhelm’s Plants of the Chicago Region and current research.
Size:
Mature great blue lobelia typically reach 2 to 3 feet tall and 1 to 2 feet wide. They primarily spread through self-seeding.
Native geographic location and habitat:
Great blue lobelia is native to Eastern and Central United States. C-Value: 4.
Attracts birds or pollinators:
Great blue lobelia attracts hummingbirds, butterflies, beneficial bees, and caterpillars.
Leaf description:
The leaves of great blue lobelia are sometimes long and narrow with tapered ends (ovate or broadly elliptic) or may be more rounded at one or both ends (oblanceolate to obovate). The leaves are a medium yellowish-green in color. They can grow to approximately 5 inches long and 2 inches wide. The leaves occur in an alternate arrangement with the lower leaves clasping the stem and the upper leaves attaching to the stem without stalks (sessile). The edges of the leaves are irregularly serrated.
Flower description:
Great blue lobelia produces flowers that are slightly larger than other lobelia species. The central stem of great blue lobelia terminates in ½ to 2 feet of densely positioned flowers that start to spread slightly as they descend the stem. The flowers occur on individual stalks (pedicels) along the central stem (raceme inflorescence). Each flower has a purplish-blue, bell-shaped, petal-like tube (corolla) that divides into two lips (bilabiate). Each lip is divided into lobes, with the bottom lip divided into three lobes and the top lip divided into two lobes that curve backwards.
Between the two lobes of the top lip, the reproductive structures protrude slightly. Between the three lobes of the bottom lip, near the throat of the corolla, are two white bumps. The bottom of the corolla tube has dark bluish and white stripes. Surrounding the base of the corolla tube are long, narrow, leaf-like structures (sepals), split into five teeth, that form the calyx. The calyx is hairy (pubescent).
Fruit description:
Great blue lobelia develops two-chambered, dry fruit (capsules) that contain numerous seeds. The calyx that once surrounded the corolla tube persists when the fruit develops.
Plant Care:
Lightly mulch great blue lobelia in the fall and separate clumps in the spring. This is a species that does not like to dry out, so supplemental water may be necessary. Deadheading can help to prevent self-seeding and encourages additional blooms. For more compact growth, great blue lobelia can be pinched back.
List of pests, diseases, and tolerances:
Great blue lobelia is not susceptible to major pests and diseases. They are deer and rabbit resistant.
