Please ID this purple flower with slender serrated leaves.
This is a native plant called obedient plant (physostegia virginiana). It earned this name because of it's unusual ability which allows you to actually push the flowers around on the stem, changing the direction they are pointing. It blooms beautifully in late summer when many other bloomers are tired out. It is a perennial which grows in creeping patches. Some might call it invasive, but it is very easy to pull should it go out of bounds.
Pollinators visit it often.