This is my backyard oasis:

Please ignore the weeds, it's taking some work to get them all out in 95 degree weather without using herbicides :-(

I'm specifically looking at the area between the boulder waterfall and the fence. It's about 10' long and 6' between between the pond and fence, and currently empty other than some muscadine vines and false Virginia creeper.

On the sides I have elephant ears, yellow canna lilies, and nandina. Then a little farther out are a variety of irises, daylilies, sedum, campion, and so on.

What I need is something that'll go well with the leafy elephant ears and cannas that would be right next to it, be tall enough to be seen over the boulders, but also be narrow enough that I can get past it when I need to get to the pond filters (just behind the boulders).

The area does stay a bit moist. The roots would be shaded by the boulders, too, but the top of the plant would be in full sun (direct sun, all day).

My first thought was hardy banana trees, but honestly, you see those outside of EVERY mobile home park in my area! And that kinda turned me off a little.

My next thought was Sunshine Ligustrum shrubs. I have a few of those, anyway, and could plant cuttings here. The leaves would be similar to the nandina, so against the tropical plants would have a sort of Bohemian vibe.

What else should I consider?