It's Clerodendron indicum. Somebody in comments guessed "Clerodendron" and they were right. Another common name is "turk's turban" for the reflexed-backward petals that look (well, it's a stretch) a little like a hat; also "skyrocket" and "bowing lady."
Native to China and Southeast Asia, it grows in Southern states of the US; a perennial, it can be invasive. It's an old-fashioned flower; my neighbor says it was growing on his property before he came there.
Its seed pods are maturing right now, I hope to gather some seeds.