I fell in love with this tree in Key West. Though some of the dwarf Poinciana's will return in spring and bloom. (As Pride of Barbados) I'm of the impression the Royal only grows as far north as central florida. You might want to check in the florida group. Where they're more familiar with this plant.

A large Royal Poinciana in bloom is a sight to see.

According to Floridata this tree should not be exposed to temps below 45. Which should rule out all of us excpet perhaps the mouth of the river.

Here is a link that might be useful: Floridata info on Poinciana