Vinca is a classic low maintenance perennial flower - so is pentas. Both come in shades ranging from white to pink to red to maroon. Pentas have the added advantage of attracting butterflies. Lantana montevidensis ( a mounding/trailing type), another perennial, also comes in a number of colors: white, yellow, orange, lavender & multicolored - also a butterfly attractor.

Floridata.com has a nice feature that allows you to search FL friendly plants by their characteristics, like flowers, vines, shrubs, annuals, perennials, etc...

http://floridata.com/plantlist/

Great! Thank you so much :)

Ixora is another low-maintenance blooming plant.

A photo of the area would be most helpful. There are hundreds of plants that might fit your needs, but to blindly suggest one without seeing where they're going, what sort of sunlight they will get, and how much irrigation is available, is a shortcut to disaster.

Addendum on Wild Petunia:
If you are looking for something for winter blooms, this won't be a good choice. After our frost, all my Wild Petunias have gone dormant. I know from experience that they will come back, so there is no fear there, but at the moment the area looks quite barren with all the browned twigs. Some reseeds are already _just_ poking their heads through the mulch though.

Just a reminder: original query was about lower growing flowers - less than 24 inches tall.

Knock out roses are nice. They don't get too tall and don't seem to mind a little bit of shade.

If you do Pentas, stay away from white. For some reason they end up dying off. Also, pentas really need to be Dead-headed, cut back, and fertilized on a routine basis. They will get very ratty looking of not done. If the area is part sun/filtered sun you can use Begonia odorata. Will get a little taller than 2 ft. but doesn't grow fast and you can cut them back.

Eh. I plant and forget my Pentas and they always end up being the among the best looking plants in my yard. They're also self-cleaning. Mine are the tall, non-dwarfed variety and wouldn't fit Bridget's requirement of under 2 ft, but I have had the dwarf varieties as well with very similar results (though they didn't attract nearly as many pollinators as the non-dwarfed). I've taken cuttings from mine and planted them at my mother's and mother-in-law's houses and they were doing marvelously until the cold got them.

Two pictures of my old 'butterfly bed' from my second summer of gardening, but first summer for this bed ('12). Red and Lavender dwarf pentas varieties (Looks like one white as well). Never fertilized, never dead-headed. Just a full summer of neglect. It was even on the northeast side of my house, the area that gets the least amount of rain during the summer due to the house blocking much of it.

A picture of my non-dwarfed red Pentas (3-4 ft). Again, neglected, though this one sat in a bed that had 2 years worth of chipped tree mulch on it. The above one was a sandy pit with a thin layer of pine bark (I didn't know about amending soil and proper mulch thickness then).