About 300 species of perennials and annuals from the northern temperate zone, especially the Mediterranean region, plus a few on tropical mountains. (Almost half the known species are native to Europe). The dwarf species described are mainly herbaceous perennials of tufted, clump or colony-forming habit with a variety of leaf shapes, and bell-shaped flowers having five petal lobes. In some species the flowers open wide with long petal lobes and have a star-shaped appearance. With only a few exceptions the flowers of campanulas come only in shades of blue, purple, violet and lavender and open in summer.
Campanula is one of the standard rock garden genera, having much to offer in beauty and ease of cultivation. Some species are tricky, needing raised bed, scree or rock crevice conditions. Others dislike too much winter wet or are not reliably hardy and thrive best in the alpine house. Special requirements are mentioned under the species' descriptions. Moderately fertile, well drained but not dry soil and a sunny site suit most species. Propagation is by seed in winter or spring in a cold frame, by division in early autumn or spring and by basal cuttings of non-flowering shoots in late spring or early summer.