a picture of the leaves would allow me to scan the web for something similar.

Have you looked through the asian oriental veggie seed catalogs. Kitazawa does not put pictures in their catalog but has pictures online. Then there is the big seed company up in Canada

www.agrohaitai.com/ .
www.evergreenseeds.com/vegetableseeds.html
www.kitazawaseed.com/

google has a long list of companies. Searching them has to find the seeds. Let us know what you find.

Did you buy the greens and taste them.

You can phone Kitazawa and they might know what the seeds are. they use a long list of the oriental names.

Just happened to stumble upon this question and I do have the answer. It is called Japanese Mugwort. Sook is what this plant is called in Korean. Hope that helped.

Kitazawa has this on pg. 22.
This flavorful herb for dumplings,stir-fry & soups.
Yomogi or kui hao are other names, 45 days from seeds.