Corydalis lutea – (syn. Pseudofumaria lutea) – Golden Corydalis is quite vigorous in our cooler coastal gardens and some might consider it a bit invasive (self-seeds), but it is easily removed when young. It features bright yellow blooms over green ferny foliage from May to September and tolerates shade to full sun here. Grows 8-16″ high by 10-16″ wide. Zone 5.
Corydalis ‘Blackberry Wine’ – A newer cultivar with fragrant purplish-pink flowers from May to July (more flowers in spring) over fern-like bluish green foliage. ‘Blackberry Wine’ definitely blooms longer in areas with cooler summers, such as coastal BC. It is semi-evergreen and prefers partial shade or filtered light. Grows 8 to 12″ high by 8 to 18″ wide. Hardy to zone 5.
Corydalis ochroleuca (syn. Pseudofumaria alba) – White Fumewort features unusual creamy-white flowers (with contrasting greenish-yellow throats) from late spring through to summer over greyish-green ferny foliage. This evergreen species can be short-lived but readily self-seeds to replace itself. Grows 12″ high by 16″ wide. Hardy to zone 5.
Corydalsi flexuosa ‘Purple Leaf” – An attractive cultivar with bright purple-tinged electric-blue flowers (blooms more reliably than ‘Blue Panda’) with white throats from March to April over green ferny foliage with bronze-purple highlights. May go summer dormant in the heat and prefers partial shade with fertile, well drained soil. Grows to 12″ high . Hardy to zone 5.
Corydalis cheilanthifolia – This species is native to China and has very fern-like mid-green foliage similiar to the fronds of Cheilanthes or Lip Fern. It bears spikes of golden-yellow flowers from spring through to summer, with the foliage eventually turning bronze and persisting through winter. Ferny Corydalis grows 9 to 12″ high by 20″ wide. Hardy to zone 5.