Terese, some of my very old Alpinia plants are pretty large, the longest stems being nearly 5ft. But it's in nearly full shade having been overcome by a huge bougainvillea over the years, so it's probably 'reaching'. Others in more light form nice neat clumps about 3ft. tall. It's a really beautiful plant but it does like to stay moist, especially where it's growing in the sun.
If it were my house, I'd want more drought tolerant plants there, as keeping the walls of the house wet for the sake of a flower border isn't that great an idea in Florida. Usually recommend you not plant anything within 2ft. of the house walls, just so you can keep them dry. It prevents water incursion if the house is concrete block, and insect invasion if it is frame.
I guess what I'm saying is, by all means plant stuff along the outer edge of that border, but keep the area right next to the wall, under the overhang dry if you can. If there's no gutter on that part of the roof the plants will get good water in summer when it rains, but try to keep irrigation from wetting the part in by the wall if you can.
A gorgeous butterfly and hummingbird plant, red firespike,
Firespike (Odontonema tubaeforme) would do very well there. It can get large, but a snip here and there will keep it in line. It would screen the view of your AC really nicely. Btw, don't plant anything too close to the AC either, it blows off hot air all summer, and most plants don't like that, plus you need space around it for it to work properly.
