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Corydalis

© Marge Talt

Corydalis. Some you love; some you hate and some will always be an unrequited lust if your climate doesn't suit them. When happy, they are tough plants, despite their fragile, semi-transparent stems - like spun glass; not plants that appreciate being slept on by the dog or stepped on by the ham footed garden visitor.

With some three hundred species in this genus, few can boast of growing them all, particularly since many are not in cultivation. Corydalis (fumewort) belong to the Fumariaceae family as do their close relatives Dicentra, the bleeding hearts, although they're often placed in the closely related Papaveraceae (poppy) family. They are either fibrous rooted or tuberous annuals, biennials or deciduous perennials, all with ferny blue-green foliage and clusters of small tubular flowers that range in color from white through cream to bright yellow, rose shades to brickish red and ice blue to purple. Most flower in spring, but some species will produce flowers all season from spring to frost.

They are mostly native to the woodlands of Asia and Europe although there are several species native to the US and Canada, including:

C. aurea	C. caseana	C. caseana ssp. aquae-gelidae	C. curvisiliqua
C. crystalina	C. flavula	C. micrantha	C. scouleri
C. sempervirens	C. pauciflora, an Asiatic species who's jumped the Bering Strait into Alaska and Canada; the only blue flowered species in these areas.

Size ranges from diminutive plants suitable for the rock garden to the four foot (1.2m) C. caseana ssp. aquae-gelidae , a rare native North American species. I have tried in vain for several years to get the charming annual C. sempervirens to establish in my garden, both from seed and purchased plants. It's supposed to be easy, but I have yet to have a plant survive long enough to set seed. I shall persevere as its bicolored pink and yellow flowers are enchanting. I may have been putting this in too much shade; in too rich and organic a soil. It's said to grow best in full light, on dry, gravelly soil or in open, thin woods.

The holy grail of Corydalis are the intense blue forms from the flexuosa group. I am not alone in finding this a difficult group of plants. Posts to gardening email lists from people all over the country report total failure. Hailing from China, the incredible blue forms, including 'China Blue' 'Pere David', 'Purple Leaf', and 'Blue Panda' either promptly die or flower beautifully, go dormant and never return or succumb to winter. 'Blue Panda' is usually listed as a flexuosa type, but some respected plantsmen consider it a form of C. elata, whichever...it loathes my garden.