Lobelia siphilitica

Blue lobelia’s flowers have an air of formal elegance that makes for a charming interaction with their rough-and-ready pollinator, the bumble bee. The flower is in the bilabiate class, characterized by two multilobed lips bordering a cavity into which bees crawl when seeking nectar. It is a delight indeed to watch the bumble bees work, rummaging for nectar in spaces that seem much too dainty for them, their hind portions protruding conspicuously from the flower openings. The bumble bee’s proportions actually make it a perfect pollinator here, maximizing contact between the bee and the plant’s reproductive structures, which overhang the flower entrance. Although bumblebees are the primary pollinators of blue lobelia, the plant attracts a variety of bees of varying sizes, as well as butterflies.

Adapted to both full sun and partial shade, blue lobelia grows well in soils of wet to moderate moisture, and its native NE Ohio habitats include low-lying woodland edges, wetlands, fields, wet meadows, and riparian areas. As a point of interest regarding local adaptation, some research suggests that the success of naturally occurring blue lobelia populations may be due, in part, to optimized interactions with co-occurring fungal communities which enhance the plant’s phosphorus uptake. In the garden, blue lobelia may be expected to attain a height of 1-4’ and to bloom for approximately 2 months in the latter part of summer. Although the plant may multiply somewhat through seed production, it tends not to form colonies or grow aggressively.