I have several flower beds with only native perennials. This year the color and character of the plants aren't strong and vibrant. Should I put a lot of compost on them or will this stress them more? Several natives don't like rich soil on their roots. [/code][/quote][/i]

It's true that a lot of native texas plants are more adapt to dry "bad" soil, like black foot daisy for instance. As long as they're getting plenty of sun (assuming they are full sun plants) and you're not over watering, you may want to give them a shot of bioform or something similar. Bioform is a fish/seaweed emulsion that can be used as a foiliar spray or you can douse the roots. Unless it's been a few season since you put fresh compost in your bed, you probably don't need to add any.