The history of Corydalis, how they are saving the clouded Apollo butterfly, and the quest for something blue.

Every year, in small under attended meetings across the world, Entomologists select an Insect of the Year, to the eager anticipation of nearly no one. In 2021, as an example, the Czech Entomological Society bestowed the honor to the Parnassius mnemosyne, named for Zeus’ aunt and the goddess of memory. Known commonly as the Clouded Apollo butterfly, the species is critically endangered there and considerable effort is being made to restore it. In 2003, the specimen count in the Bulhary Preserve was over 4,000, but dropped to less than 100 in 2019. The Czech Republic is not the only European country to observe this decline; Finland and Sweden have launched conservation efforts too. Its habitat is the mosaic meadows and pastures adjacent to deciduous forest edges, which have disappeared in large parts of Europe, partly due to overgrowth, afforestation, exploitation and excessive grazing. But don’t get too discouraged. In response to rehabilitation strategies, the Clouded Apollo is slowly making a return. The key to their survival, it turns out, is the Corydalis, their main food source. Wherever the Corydalis thrives, the clouded Apollo can too.

Portrait of Parnassius mnemosyne, by Didier Descouens,

Corydalis is a genus of about 470 species of annual and perennial herbaceous plants in the family Papaveraceae. They prefer a neutral or alkaline pH and particularly thrive in temperate Northern Hemispheric locations; they are most diverse in China and the Himalayas. Corydalis are close relatives to the Bleeding Heart, and share a similar dainty leaf pattern. The genus name is a derivation of the Greek ‘korydalis’, or crested lark, apparently as reference to the spurs on a lark’s head. Larkspur, incidentally, is a common name of an entirely different genus (or rather two): the perennial Delphinium species and annual Consolida species.

Corydalis solida has been planted in gardens since at least the sixteenth century. Deep pink and red forms were particularly sought after and the ‘Zwanenburg’ subtype is considered the finest red form. It has been known to change hands for three figure sums. These days, bluer varietals seem to stoke the most envy. In 1989, three Englishmen, James Compton, John d'Arcy and Martyn Rix, ventured out on a daring but successful plant expedition to Western China (the Woolong Valley of central Sichuan Province) to harvest Corydalis flexuosa’s three blue subtypes: Blue Panda, China Blue, and Pere David.