Why are my plants fading so badly?

The colors on most of my plants in a particular flowerbed are all fading out, almost as if they are bleached out. The flowers, even the foliage are turning white. It's not hot here yet, the temp has been in the 80's and all my plants are pretty hardy for our climate which is an average of 94-98 degrees in the summer. One of them in particular is a hibiscus and another one is a butterfly bush. Could this be some kind of disease or fungus?