I wish I lived in your zone. If I did I would have bananas, cannas, bird of paradise, and portulaca for color on the bottom.

Also try some Pride of Barbados, ginger lilly, and bouganvilla for color! I would love to be in your zone too. Don't forget some windmill palms, queen palms or maybe pindo palms. I have found that as far as designing a tropical garden, there really does not seem to be any right or wrong designs. Its what you find pleasing to your own eyes. Remember that nature does not necessarly have a blue print. She does what she likes ;)
Have fun! :)

Hi gurley157FS,I live in zone 7 and grow bananas,cannas etc.You can to.Pictures below.john

Here is a link that might be useful: zone 7