Members of the Corydalis genus are low growing (15 to 60 cm) hardy annuals, bulbs or perennials that have leaves that look like those of ferns.
Depending upon the variety of Corydalis they may bloom at anytime form the early spring until the autumn, carrying tubular flowers of yellow or blue.
Some common names for Corydalis include Fumitory and Fumewort.
Corydalis ambigua by Arudhio.
Common Names: Fumewort, Yan Hu So, Fumitory, Scrambled Eggs, Golden Smoke, Rock Harlequin. Corydalis: Gold; Yellow; Blue; Ferny; Climbing.
Life Cycle: Hardy annual. Hardy Biennial. Hardy bulb. Hardy perennial.
Height: 4 to 36 inches (10 to 90 cm).
Native: Northern hemisphere temperate regions especially China; and Eastern Africa.
Growing Region: Zones 1 to 9.
Flowers: Early spring, summer and autumn.
Flower Details: Yellow, gold, blue, purple, red, pink, white. Tubular. Clustered, often in racemes.
Foliage: Many shades of green, grey-green. Fern-like.
Sow Outside: Seeds: Surface. Tuber: 3 inches (8cm). Annuals: spring or autumn. biennials and Perennials: Summer or Autumn. Spacing 4 to 16 inches (10 to 40 cm) depending upon species size.
Sow Inside: Much easier to grow from tubers. For seeds the germination time is one month to one year. Stratify in the fridge for two or three weeks, then sow seeds on the surface and keep at 60°F (10°C) in the light until they germinate. Once you get seedlings sow them out in autumn or following the last frost.
Requirements: Partial shade. Good drainage. Soil pH 5.5 to 8. Rich soil. Humus rich. Moist soil. Supply leaf mold. Regular watering. Some species are drought tolerant. Propagate by division of tubers, rhizomes and bulbs once flowering has finished.
It is quite difficult to grow Fumitory from seeds and you may prefer to grow from a plant from the garden centre. If you prefer to grow your own fumitory then the seed should first be kept at a temperature of 17°C for 8 weeks, then chilled in the fridge for 2 weeks. The seed should then be sown onto the soil surface when the temperature is at around 18°C. Alternatively you can plant Corydalis (fumitory) bulbs at a depth of 7 cm at the beginning of the summer. Seeds or bulbs should be planted into a lightly shaded area of the garden with good drainage. Ideally the soil that Corydalis grows in should be rich and of a pH 6 to 8.
It is important to cut back the plants after flowering as they are able to self seeds. As they are difficult to grow from seed then you may like to divide Corydalis perennials once flowering has finished.