Oh neat. Congratulations. You said you cleaned the area up. That must have given the peony an opportunity to flourish. As ianna wrote, fall is the best time for moving. Last year, I cleaned out a heavily overgrown bed. This year a peony popped up - isn't that funny? I experienced the same thing as you. littlebin posted this link on the peony forum. It's relevant to your question regarding sun exposure and flowering. A friend of mine has found that a couple of cultivars do well in partial shade, but very few. Here is a link that might be useful: Sun Shade

Arum italicum. Around here, it spreads easily but is a tough one to get rid of. Make certain you want it. If not, start digging now.

thedecoguy, I did some searching on Petasites and it certainly looks like it matches what she described. I've never seen anything like it before. Thank you! I'll pass along the info and see what she says.

There is a percentage of the genus Sedum - and not the entire genus - that got split off into Hylotelephium, of which the familiar 'Herbstfreude'* is but a single example - without open flowers being present plant asked about might just turn out to be another one. *"Autumn Joy" is a translation into English of the German cultivar name, and not that the plant's actual cultivar name. Same as if somebody from the US went on vacation to a Spanish-speaking country and everyone there wanted to call her Maria, her name would still be Mary nonetheless