Quick Guide: summer, hardy, sun/semi-shade, height: 23cm/9in, width: 30cm/12in

Although the common name for campanulas is bell flower, not all the species bear flowers in this form. A number have starshaped blooms, including two of the best species for rock gardens. Campanula carpatica (above) forms neat, bushy tufts of green, heart-shaped leaves and bears abundant blue, pink or white flowers 4cm/1 1/2in across on erect, wiry stems. C. garganica is a rewarding choice - over the whole of the summer it bears so many blue flowers that the leaves are hardly visible. Both spread up to 30cm/12in.

GROWING Plant in well-drained soil in sun or partial shade between autumn and spring. Remove flower heads when faded.

PROPAGATION Take 2.5cm/1in basal cuttings of non-flowering shoots in spring. Place in a peat/sand mixture in a cold frame until rooted. Pot up individually and grow on until planting out in the autumn.

VARIETIES The species are reliable, but good named varieties include: G. garganica: `W. H. Paine', deep blue with a white eye; `Hirsuta', grey, hairy leaves - protect from damp with an open cloche over winter. C. carpatica: `Ditton Blue', only 15cm/6in high, indigo; `White Star', 30cm/12in high, pure white; `Turbinata', compact shape, blue flowers, hairy leaves need winter protection.

POSSIBLE PROBLEMS Rust.