A rose can take up to a year if you start it from seed, but if you take a cutting and give it the proper amount of light and water then it will usually bloom it's first season. There are quite a few roses that handle hot weather quite well. Here is a site that shows you how to propagate a rose cutting.
http://www.scvrs.homestead.com/Cuttings1.html
Here is a list of roses that do well in hot humid climates. Stay away from the hybrid teas though. Hot may be good, but humid is not. They suffer from disease too easily.
http://www.weeksroses.com/RoseClimateHotHumid.php

Oh, by the way, in case you decide that a rose will not work, 6 months is enough time to grow just about anything.

Good luck