A diverse group of shade loving, low growing, hardy perennials with attractive dainty flowers. The common yellow flowered form (C. lutea) can often be found growing wild in UK gardens.
Botanical Name: Corydalis
Common Names: Fumitory, fumewort, Pseudofumaria
Foliage: Deciduous, deeply cut, fern-like leaves.
Flowers: Racemes of spurred tubular flowers. In shades of yellow, white, red, purple or blue, depending on species.
Flowering Period: Spring and summer, depending on species.
Soil: Moist but well-drained, fertile soil (chalk, sand or loam). Acid, alkaline or neutral pH.
Conditions: Sun or partial shade. Best in an east, west or south facing aspect.
Habit: Low growing, clump forming.
Type: Mainly tuberous or rhizomatous perennials.
Hardiness: Most varieties are fully hardy in the UK.
Cultivation varies from easy to difficult, depending on the species. Check plant labels before buying.
Most forms thrive in sunny or cool shady situations, in moderately fertile, humus rich soil. C. solida prefers a dry soil.
Garden varieties are useful in a shady corner of the rockery or as a border perennial in dappled shade. Other forms are ideal for light woodland sites or for under-planting of deciduous trees and shrubs.
Keep the soil moist (but not waterlogged) during the growing season.
Susceptible to attack by slugs and snails. Generally disease free.
Sow seed in autumn or winter. Can also be increased by division in spring but take care as the tubers are brittle.
Corydalis 'Canary Feathers' is a popular hybrid with ferny blue-green foliage and clusters of vibrant yellow, tubular flowers on upright spikes. Height to 12in (30cm), spread to 24in (60cm). For sale at Van Meuwen.
Corydalis cashmeriana (Kashmir corydalis) has pretty sky-blue flowers in June. Prefers a cool, humus rich, lime-free soil. Height up to 6in (15cm).
Corydalis cheilanthifolia (fern-leaved corydalis) has bronzed ferny foliage with dense racemes of yellow flowers in spring and summer. Tolerates most soils. Increases well from self-sown seedlings.
Corydalis flexuosa (blue corydalis) has finely divided glaucous leaves, topped with clusters of two-lipped blue flowers with white throats. Height to 1ft (30cm). Varieties include:
Corydalis lutea (yellow corydalis or rock fumewort) is an easy to grow yellow flowered form with fresh green ferny leaves. Flowers from March to May. Height to 12in (30cm). Self seeds readily.
Corydalis solida has delicate foliage with purple-pink flowers. Useful for a dry, shady situation. Height 4-10in (10-25cm).