I have a volunteer plant growing in a basement window well. The leaves are unlike anything else in my yard. Anyone know what it might be?

https://www.google.com/search?...

And if it is bigger than that, perhaps a mimosa.

wow, that's sure what it looks like!

wow--well, if it is a tree, then my basement window well is probably not a good location for it!

If it's the plant, then it will die with our first frost...

What is the height of the plant from the soil line? Sensitive Plant (Mimosa pudica) is a non native but found in Maryland. It's a low grower but stems can grow to 5 feet in length according to the listing at wikipedia: https://en.wikipedia.org/wiki/... Have you noticed if the leaves close up at night? Also, try touching the leaves and see if they fold as is common in Sensitive plant.

If it is Mimosa Tree (Albizia julibrissin) it's very invasive, even in Maryland! http://www.mdinvasivesp.org/ar...

If it's the sensitive plant, then you should be able to tell immediately by touching it, because it will fold up as in this video. They're lots of fun

https://www.youtube.com/watch?...

(Cross-posted with Lin)

I did try touching it but only gently. It didn't have much of a reaction but I noticed the leaves were already partially folded compared to my earlier photo--maybe from the wind? I'll have to give it more of a thump.

Right now it is in the 18-24" range.

That's good to know about the invasive status of the tree!