This popped up in a planter. I feel like I should KNOW what it is, but

poplar perhaps

I'm thinking sycamore.

HMMMM...don't have any poplar that I know of, but I do have a HUGE sycamore. I'll grab a leaf and compare after the rains stop. Also while standing in the screen room enjoying the wonderful scent of wet earth, I was looking at an American beautyberry...also possible??? calling for sun and no rain tomorrow...will compare leaves. Thanks

sycamore it is....didn't recognize it in "babyhood" The momma tree is so big that it would totally demolish my house if it fell on it

Ginger, you should add some photos to the database. I think that young sapling photo and the leaf photo would be helpful to others possibly trying to identify that tree: American Sycamore (Platanus occidentalis)

Consider it done