Corydalis heterocarpa (Japanese Fernleaf Corydalis) [15 Seeds]


Germination Information: I recommend these seeds only for gardeners with experience sowing challenging perennial seeds, because there’s little information about germinating this species. I used my standard corydalis protocol to start the original seeds: Sow about 1/8″ deep as soon as you get them and set the pot outdoors in a protected spot, so they can sprout whenever they are ready, either this year or next.

As I mentioned in the description, the plant can self-sow freely once you get it to flower in your garden. I was surprised to already find volunteers popping up around the parent clump in early July in the very first year it flowered. So, apparently it’s possible for very fresh seeds to germinate quickly (within a few weeks) if sown in warm, moist conditions. Once they dry out, though, it may be that winter chilling is helpful.

Note that this information will not appear on the seed packet you receive.

Please read the description as well before ordering.

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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.

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