It is bloodroot, Sanguinaria canadensis. Native to the U.S.

Thanks. I saw that one online and wondered if that was what it was. The leaves looked similar but I didn't think it looked tall enough from the pictures I saw. Actually looking at descriptions of the plant again it must have flowered already. I have lots of different things flowering in early spring so perhaps I didn't notice it. But I don't remember seeing flowers quite like that. I'll need to look more closely next spring.