The genus is made up of annuals, biennials and perennials, and there is great variety in the size of the plants. They range from stately tall plants that give height to beds and borders, to mat-forming, spreading ones that are useful in rock gardens.
While all of the flowers come in shades of blue or white, they are not all shaped like bells despite their name. 'Canterbury Bells' however, are aptly named. They have big bell shaped blossoms that face upward and the pistil reminds one of bell's clapper. Also aptly named is the "cup and saucer" flower with flaring petals near the stem.
Low growing campanulas, 'blue clips' and 'white clips' hold their cup-shaped blossoms erect on wiry stems. There is a crisp clean simplicity about these flowers when they appear in the late spring.
In general, campanulas like full sun to partial shade and soil that is moist but well drained. 'Campanula Glomerata' grows about two feet and has deep violet-blue flowers in June in my Indiana garden. It is best to buy plants at local garden centers to obtain the best varieties for this area. Those bells appeal to all who enjoy visual music in a garden.