The bell-shaped flowers, usually pale blue, mauve or occasionally white, mark these plants out as Campanula relatives. Most are climbers, so are best planted at the bases of small shrubs, which they will decorate with flowers for a second time each year. Flowers repay close inspection, having beautiful, brightly coloured patterns inside, but beware, for most species have a rather unpleasant, foxy smell coming from their foliage. Growth starts late in the spring, and the stems are surprisingly slender for the vigorous growth that follows. In contrast, the fleshy roots are substantial.

Codonopsis thalictrifolia subsp. mollis is mat-forming with lovely, delicately cut foliage and pale blue, narrow bellflowers.