Quick Guide: spring, hardy, sun/ semi-shade, height: 20cm/8in, width: 45cm/18in

Corydalis lutea is the common yellow fumitory often found growing wild on old walls. More garden-worthy are C. cheilanthifolia (above) and C. cashrneriana. The former shares with its wild cousin a tendency to self-seed, which in the less formal settings which it suits may not be a problem. The fern-like foliage is slightly bronzed, arranged in tufts from which rise dense racemes of long-lasting yellow flowers. There are no named varieties. The species C. cashmeriana is a fussier plant, requiring cool, humid conditions, but its beautiful blue flowers make it well worth growing in areas where the climate is suitable.

GROWING Plant in spring on any good garden soil. C. cashmeriana must have cool, peat, totally lime-free soil.

PROPAGATION Self-sown seedlings of C. cheilanthifolia do well. Corydalis may be increased by careful division of the delicate tubers in early autumn. Replant immediately.

POSSIBLE PROBLEMS Generally trouble-free.