I have had trouble growing blue bulbous Corydalis (C.turtschaninovii-type), they slowly decline, or at best stay the same. Maybe I haven't found just the right place and soil for them earlier, because now this C.turtschaninovii looks fine, and last spring was it's second spring here.
Corydalis buschii does very well, it is even a little weed-like so that when I have moved it, it grows back from the tiniest root piece.