"...a gardener who knows his flowers and is ignorant of his weeds is like half a coin, a tail without a head." Sara B. Stein
Oooh, a native! And how pretty!
I'm afraid this may be lesser celandine, a marsh marigold look alike. Apparently the two are very difficult to distinguish. This article has some tips to tell them apart.Unfortunately, lesser celandine is invasive.
Thanks Theora. I love this kind of feedback! I'll adjust my labels and links later.