What gardener with a heart and soul could resist the spring flowers of Corydalis, whose winged petals with upswept spurs suggest a flight of elfin butterflies, or, for that matter, their lacily divided leaves, which come in a kaleidoscope of colours from grey to deep green.
Corydalis solida are perky little denizens of forest and mountain. A hardy perennial, native to Northern Europe and on into Asia, where they grow in meadows and woodlands. A light shade and moist soil offer ideal growing conditions but overall, they’re pretty forgiving plants.
Easy to grow from seed, the plant forms a tuberous bulb that produces dense clumps of flowers that get better each year. In spring the deeply divided, ferny leaves and narrow, long-spurred flowers appear. The 2.5cm (1in) large flowers together fairly dense clusters at the end of the stem. The colour of the leaves and flowers varies considerably from white to pink and purple, and deepens after colder winters.
Blooming from April to May, and reaching 20cm (8in) tall at most, it gently mingles among other woodlanders and smaller bulbs. By early June, the plant dies back and simply disappears leaving space in the garden for the summer bloomers. It one of those accommodating plants that dies back quickly without leaving messy foliage. Their disappearing act classifies them as ‘woodland ephemerals,’ which can come in handy if you’ve a crowded garden.
Corydalis are highly useful at the front of a woodland border, with crocus, in front of dicentra or with miniature bulbs such as muscari or scillas. They can also be grown in pots of gritty soil, but keep compost cool and moist in summer. Partnered with hostas or hardy geraniums, they break into leaf after the corydalis vanish.
Sowing: Sow seeds in late spring/early summer or late summer/autumn.
Corydalis seeds need a period of cold and damp to enable them to germinate. They can also be sown during warmer times of the year, but it would be necessary to artificially simulate the fluctuating temperatures of winter using stratification as below.
Sow from June onwards on a surface of seed compost, cover with grit and keep in a shaded cold-frame or cool glasshouse. Sow seed 2.5cm (1in) apart in trays or cells containing good quality seed compost. Sow the seeds on the surface of the compost, but do not cover the seeds as they need light to germinate. Place the container in a light position at a regular temperature of around 16°C (60°F) Germination should take place between 21 and 40 days.
If you are planting during warm periods of the year, and wish to sow your seeds into pots (it not directly outdoors), you may wish to use stratification to enable to seeds to germinate quicker. This method simply artificially simulates the fluctuating temperatures of winter.
Place the seeds between two pieces of damp filter paper or folded kitchen roll then put into a polythene bag and place this into the fridge at 4°C (39°F) which is the temperature that most fridges are set at. Inspect the seeds after two weeks and remove as the seedlings appear, returning the ungerminated seeds to the fridge.
When seedlings have their first pair of true leaves and are large enough to handle, transplant into 7.5cm (3in) pots containing peaty compost. Grow on then gradually acclimatise to outdoor conditions for 10 to 15 days before planting out. Plant them in a humus-rich, moisture retentive soil and in partial shade.
Germination can be erratic, although most should germinate in four to five weeks, it is not unknown for seeds still to be germinating up to four months after sowing. Remove the seedlings, transplanting them to individual pots. Place the original container in a shaded corner of the garden….just in case!
Corydalis seeds grow into a spherical tuber of about 1 to 3cm (½ to 1¼in) in diameter. Most tuberous plants need good drainage. However, Corydalis solida differs from many in that it does not appreciate a hot, open bake during summer. Plant in dappled shade where the ground stays cool and on the moister side. A strong plant should double up yearly. Watering the soil with diluted fertiliser soon after shoots start to emerge encourages tubers to increase well.
Mark the position of the plant with gravel and divide when dormant in late summer or early autumn. Allowing this type of corydalis to set seed will produce a variable crop, but they will form a pleasing, spangled colony. If you want to keep a plant pure, deadheading is the only route.
Shade and Woodland gardens, Borders and Underplanting.
There are about 450 species of Corydalis, many of which, around 330 species are native to China and Tibet. Corydalis solida is native to Northern Europe and Asia and is found in diverse habitats such as meadows or woodlands.
In Northern Europa, Corydalis solida is the most common flower in its genus. It is found in Sweden, southern Finland to the Urals, central Europe, Spain and Greece. Absent as a native from much of W. Europe, it was cultivated in Britain by 1596 and was first recorded as naturalised in the wild in 1796.
The flowers naturally show colour variation, and may be mauve, purple, red, or white. Red and pink forms of Corydalis solida are mostly found in the mountainous region of Transylvania in Romania.
Formerly in the fumitory family, Fumariaceae, it is now included in the poppy family, Papaveraceae
The species was originally named in 1753 by Linnaeus as the variety solida of his Fumaria bulbosa. It was changed to the species Fumaria solida by Philip Miller in 1771. Its current assignment to the genus Corydalis was made by Joseph Philippe de Clairville in 1811.
The name corydalis comes from the Greek korydalis, meaning ‘crested lark’ referring to the shape of the flowers. The flowers have spurs like a lark.
The species, solida, is from solido, meaning to make whole.
It has the common names of Bird-in-a-bush, Fumewort, Solid-tubered corydalis or Solid-rooted fumewort
Syn. Corydalis halleri (Willd.), Corydalis transsylvanica.
- Additional Information
Packet Size 50mg Average Seed Count 30 seeds Family Papaveraceae Genus Corydalis Species solida Common Name Bird-in-a-bush
Hardiness Bulbous Perennial Flowers White to pink and purple Natural Flower Time March to April Foliage Deeply divided, ferny leaves Height 20 to 25cm (8 to 10in) Spread 20 to 25cm (8 to 10in) Position Light Shade