I purchased seeds of Corydalis magadanica and they turned out to be this species, C. heterocarpa, instead. I can’t say I’m too upset, though, as it has been exciting to watch its progress. In its first year, it formed a lovely, 18-inch-tall mound of deeply cut, blue-green foliage. At that time, it was growing in full sun and seemed perfectly happy there. In fall, I had to move it to a different spot; it is now growing in a site with a few hours of morning sun and shade the rest of the day, and it seems fine there too. It began flowering in the third week of April, at about 1 foot tall, with clusters of yellow blooms, each marked with a grayish plum spot. It continued producing new blooms through June (seemingly encouraged by deadheading) and reached about 2 feet tall by late June.
Like many other corydalis, this species can self-sow freely, just so you know. It was fully hardy though my PA (Zone 6/7) winter, even after having been moved. I have seen the hardiness zone range reported as 5 or 6 to 9. It may behave as a biennial or a perennial.
2022-seeds are sold out. I hope to collect again in early summer 2024. At least 15 seeds per packet.
Please read the germination information as well before ordering.