American bellflower is native to moist open woods, streambanks, and shaded meadows across eastern and central North America, and its upright habit reflects its origins: it grows tall to compete for light in places where it must earn every inch. The reassignment of its genus name from Campanula to Campanulastrum acknowledges what anyone who looks closely already knows — the flowers are not bells at all, but flat, star-shaped, five-lobed blooms quite unlike the nodding cups of its European relatives. That modification, and the white ring at the throat, make it unmistakable.

Biennial plants spend their first year as a basal rosette of rough, lance-shaped leaves, then send up an unbranched central stem the following season, ascending to as much as six feet and bearing clusters of light violet-blue flowers from midsummer into early fall. It is a pollinator magnet — bees, wasps, butterflies, and hummingbirds all visit for nectar and pollen — and it will readily self-seed in the right conditions, naturalizing into a shaded corner or woodland edge with minimal intervention. It asks for rich, moist soil and afternoon shade in hot summers, and rewards mass plantings more generously than solitary specimens.