Campanula medium comes from the rocky slopes of southeastern France and northern Italy, and it brings to the garden the stature and presence that shorter bellflowers cannot match. As a true biennial, it requires patience: sow seed in late spring or early summer and the plant spends its first year building a basal rosette of lanceolate leaves up to 6 inches long, overwintering beneath a layer of mulch. In the second year it sends up stiff stems reaching 1 to 3 feet, bearing racemes of large, showy, fragrant bells in clear blue, soft pink, or white. The cup-and-saucer form, a variant with a broad ruffled calyx beneath each flower, is particularly distinctive. Blooming runs from late spring into summer and draws bees in numbers.

The plant's principal limitation is its intolerance of heat. Where summer temperatures regularly exceed 80 degrees Fahrenheit — most of the American South — Canterbury bells struggle and rarely perform well. In cooler northern gardens and in coastal climates it thrives in full sun or partial shade, given moist, well-draining soil. Planting in groups provides mutual support and reduces the need for staking, though tall stems in exposed positions may still need a cane. For a continuous annual display, allow a proportion of the seed pods to ripen and self-sow rather than deadheading everything. The plant has few serious pest or disease problems: slugs and snails are the main hazard, and powdery mildew can appear in poor air circulation. Its deer resistance makes it suitable for rural gardens.