I remembered a thread from earlier this year on the issue of identifying a plant - that turned out to be the more common Japanese Kirengeshoma palmata. I posted on that thread as I have that one too, So today I posted a picture of the Korean one that grows in the same bed . It was doing nicely today - but then I couldn’t see the thread I posted it on appearing in the topic list! I finally figured out the thread is in the Landscpe Design forum so you need to look here https://www.houzz.com/discussions/6141368/what-might-this-be#n=8 to see it :-)