I bought this 'Confederate Rose' (Hibiscus mutabilis) about a year ago from Bioscape. The bloom starts off almost white, goes pink during the day, and the next day it's practically carmine.
There's quite a lot of variablity in the species. I think I've read that the single blooms throughout the year; this double/triple only started to bloom this week, but if it blooms like last year, it will bloom until hit by frost, and again all spring. The leaves go a bit wilty in the heat of the afternoon sun no matter how much it gets watered, but I'd say it's very drought tolerant: It made it through a dry spring without hardly any irrigation, and it's in almost full afternoon sun.