I think it's fringed loosestrife - pretty plant!
Sherry

I had to laugh when I saw the pic....I have a large clump of the same thing in my woods garden this year! Your posting impelled me to look it up, and it's a fringed loosestrife (lysimachia). Seems to be a lot of it all of a sudden--hope it's not invasive.

Look out! Most of the loosestrifes are extremely aggressive! And very hard to get rid of once they are established because every little root bit left in the ground makes another plant. Plus they seed prolifically. Lythrum is a loosestrife and it is banned in most states as an invasive plant. They all love waterways.