The blue bells of the rock campanulas are well known, and there are many different species-some too delicate for ground cover, others almost too rampant. This species (which may also be listed as C. muralis) is one of the most suitable, growing to about 6in (15cm), with violet-blue bells over heart-shaped deep green foliage in mid to late summer. It will not give winter cover.
Uses A good plant to carpet the ground at the foot of a rock garden, or to grow along and between paving. Not suitable for ground cover for a large area.
Other species C. poscharskyana, the Serbian bell-flower, has almost star-shaped blue flowers, on stems which tend towards trailing, in early summer. It grows as high as 24in (30cm) and is a more rampant plant, spreading by creeping runners and self-seeding freely.