That is Bloodroot, Sanguinaria canadensis.

Thanks...I appreciate it.

OK- I had one pop up in the middle of my alpine garden this year. (I just assumed some bird dropped a seed), but seriously, you had 'hundreds' just pop up? Oh, did you just move and this is your first spring? :>)

Nope, fifth spring...I've been pulling garlic mustard for the past three years in the area, maybe this had something to do with it? How invasive are these things going to be? I don't think I could handle being overun by another all consuming alien being.

I'm going to assume you were serious when you asked about them being invasive....

They aren't invasive whatsoever! They're native!

If you end up with too many, pot some up and give them to local wildflower lovers. Seriously, they aren't "out of control" type things. And they may well go dormant in the heat of the summer.

I was being serious...thanks for the responses. There aren't that many yet but right now my floor is covered in some very large single leave plants that looked like it may be the same thing. I haven't looked close enough yet and don't have a pic of it. Below is a pic of one section of "yard". This is all new to me and am just trying to get this land back to natural.

{{gwi:1353384}}

Looks awesome! More people should post pictures of their woods on here.

Bloodroot leaves eventually disappear from sight, usually by early to mid-summer. The other native woodland plant you might have in large numbers is "mayapple". It grows in big colonies and has relatively large leaves. It often grows in the same conditions as bloodroot. They are both very common in mature woods around here. You should consider yourself lucky.

Here is a link that might be useful: mayapple

Yup, that's a good stand of Bloodroot. It is a medicinal plant, related to the poppies.