The only one I know of that is reliably winter hardy in the Triangle is the hybrid that Plant Delights sells - I'm gonna guess at the scientific name Erythrina bidwinii. I picked up an Erythrina herbacea while in Oklahoma but I keep it in a pot and overwinter it indoors. I prefer it to the hybrid because it stays smaller though the hybrid seems to bloom for a much longer period of time.

Cherokee bean flowers on previous year's wood, so you'd have to ensure a means that at least some of the woody stems (even if only 2-3" at base) survive the winter outdoors, otherwise the flowering will be VERY late in fall, as late as around frost time in the Piedmont. Dirr mentions that it is a dieback shrub in zone 7 and 8.

Cherokee bean does have quite a bit of thorns on the wiry stems, so moving it in and out of house could be annoying, unless you do reductive pruning.

If the hybrid coral bean that trianglejohn mentions can survive and flower in zone 7b (where I have seen it), Cherokee bean should be fine as more perennial-like. The hybrid Erythrina x bidwillii is a hybrid that crossed the native E. herbacea with the tropical Brazilian native E. crista-galli.

There is at least one E. crista-galli growing in 7B in Sanford, NC. A couple of years ago a customer brought in a stem cutting of one looking to find out what it was. We goggled and identified and then promptly wanted one very badly so we begged the poor customer for the stem cutting she had brought in. She was happy to give it to us. We had no success with rooting it but the two seeds that were with it both germinated. One was mine which I grew in a pot last year and it was small but it bloomed though did not produce seeds. I was an idiot last fall and did not plant it in the ground but just pushed the pot up against the south side of my house. It has still not come out so I am kicking myself that I lost it though I have not given up on it yet. Adele

Thanks for the replies. I have obtained some seed, so if it germinates I'll keep one in the greenhouse and try a couple outdoors, well mulched, in sheltered locations.