It is a double form of Sanguinaria canadensis, Bloodroot.

Love your blooms, thanks for the post.

Thank you for the ID. I'm redoing the shade garden out back and thought this would look good. Now I can research it some more and see if it is something that I want or can grow where I am.

Bloodroot ought to be hardy in zone 6, the single flowered ones are early woodland wildflowers. Blooms here in April, the leaves disappear by midsummer. The sap is blood red. The flowers don't last very long, but it's really a charming plant.

WW

Here is a link that might be useful: Bloodroot

Hardy up to zone 4 at least