Depending on the site's soil and drainage, some of the natives that would be good are red cedar, Simpson's stopper, coral bean, sand pine, longleaf pine, slash pine, silver buckthorn, foresteria, scrub titi, black titi, firebush, rusty lyonia or myrtle oak. Many other natives could also be used. The plants are growing, but the color has faded. But, most of the new varieties show their best color in full sun. They will hold their color in light shade, but lose color in moderate to deep shade.
Coleus often show their best color when grown a little lean.
This means don't fertilize the coleus heavily, particularly with high nitrogen fertilizers nor pamper the plants. Apply a balanced slow-release fertilizer and water to promote steady, even growth. I suggest that you start new coleus from cuttings and plant them in plant beds receiving half to full day sun. You should notice that the color returns to normal. Also note though, that periods of extremely hot temperatures sometimes cause coleus foliage to pale in color.