Corydalis curviflora Blue Heron

Corydalis curviflora subsp. rosthornii 'Blue Heron' is a variety of Corydalis with an electrifying colour, gentian blue, much darker than usual blue-flowered Corydalis. Its flowers are highly fragrant. They float above bluish-green finely cut foliage, carried by red stems. This highly colourful plant blooms from April in shaded and cool areas, where its blue dazzles. In dry and hot summers, the vegetation goes into dormancy. If you have the right growing conditions, you should plant these magnificent, delicate corydalis.

'Blue Heron' Corydalis belongs to the Fumariaceae family. Its ancestor comes from the humid forests of western China. 'Blue Heron' was collected in Sichuan by Mr. Dan Hinkley. The moderately fast growth of this corydalis allows it to reach 25 cm (10in) high and 30 cm (12in) wide at maturity. It forms a compact and dense clump and can spread as ground cover thanks to its stolons. The foliage is a fairly dark green with bluish highlights and is carried on reddish stems. It is finely cut and resembles that of fumitories, bleeding hearts, ferns, or chervil. Flowering sometimes begins as early as April and ends around June or July. The flowers resemble small tubes about 2.5 cm (1in) long and have a long spur. Each flower takes on different shades of intense blue, slightly lighter to purplish, in a unique range of colours. The flowers exhale a honey scent that attracts pollinating insects. The vegetation more or less disappears in winter, depending on the climate.

The 'Blue Heron' Corydalis is a relatively easy plant to grow once you have found the right conditions for it. Plant it in partial shade with an east-facing exposure, so that it receives morning sun, or in not-too-dense shade. It needs humus-bearing, moist soil, ideally woodland soil. It doesn't mind competition from trees and bushes as long as the soil remains moist. It spreads to form colonies so will be great along a path or as a ground cover under shrubs. Choose perennials with similar requirements such as Epimediums, Ajugas, Bleeding Hearts to grow with it. It also thrives in a pot on the terrace or balcony, with regular watering.