Zone 7b (Maryland), USA. Very warm microclimate on south side of house so could be from zone 8 or 8b.
3-4 feet tall Perennial - neighbor says its been there since she moved in. Not sure if it reseeds or comes back from below ground. Deer don't bother it. Seems like magic, and want to know what it is. Was thinking maybe a dahlia but the leaves don't seem to match.
Photos below. Thanks!