How about a Phormium. There are varieties that should be hardy where you live & some do OK in a hot, humid environment. There are lots of cool colors & different varieties max out at different heights.

There are also some of the smaller bananas that stay under 10'...perhaps Musa ornata 'Royal Purple'. Blood banana is also very dramatic, but would prefer some shade.

Hope that this helps,

Dan

How about canna? I have some bronze leafed canna in my garden this year (sorry, don't know the variety). Their full height is going to be about 6-7' and they already have huge broad leaves, bigger than my head! They're very lush and tropical looking. And they love the sun!

In my zone (5), I have to dig the bulbs up to overwinter them, but you might not have to in your zone. Canna come in all different heights, leaf colors and bloom colors, so you might look into that as a possibility.

thanks for your suggestions. I haven't been able to locate a phomium, but I like that plant and might add it later. For your interest, here's what I decided on:
closest to the deck a row of tall umbrella grass and in front of this a collection of 3 different kinds of black taro: all black, black w green veins, and purple stem w green leaf/black veins. Also a very dark red canna w red flowers and a green and purple coleus. Purple potato vine as ground cover between all the other plants. I'm very happy with the look and will post pics once it fills in.

Tetrapanax (Rice paper plant) would also look nice. Very structural and dramatic.

How about datura purple metel? Mine is in a pot since i grow them as an annual. Right now it is about 3' tall with leaves that are 8" wide by 12" long. Gets beautiful purple huge flowers. Or you can get them in other colors if you want. I grew mine from seed and in less than 3 months it got this big. Probably grow faster in your warmer climate, since it didn't really start shooting up until the temps hit around 75 and above.

Lee

Here is a link that might be useful: Datura metel double purple

try a rheum. but water them plenty you could be a bit hot for them