Help!

Could you post a close up of a leaf?

It might be a herb of sorts? Just a wild guess! Does it smell when you rub your fingers over it?

It looks like lysimachia punctata, yellow loosestrife. it grows about 2FT tall with buttercup yellow flowers. can be invasive though.

I agree with Seaburngirl - yellow loosestrife

I just bought a yellow loosestrife and it does look a lot like this I have to say. it can be invasive but im told not to hard to remove if it becomes a problem. I have seen it growing to about 4 foot. the bright yellow flowers on tall spikes are something else though very pretty.