Quickly, I will go over why this usually doesn't add up. Most of the flowering evergreens that I know of have very delicate blooms, which is why most flowering evergreens require partial to full shade. When these shrubs are grown in too much sun, the blooms usually develop burn spots.
With anything flowering, usually flowers can only occur when a plant is very healthy or very sick. When the plant is very healthy, the plant is able to devote extra energy to reproductive features (I.e., flowers). When the plant is not so happy, when it reaches a point where it feels like it may die, it goes into a sort of "panic mode" and flowers as a last ditch effort to keep it's species alive. Either way you look at it, flowering with a plant just isn't something that can be done forever. It takes so much energy from the plant, that you would need to constantly feed it nutrients and water for it stay alive while flowering.
Which brings me to the next point, of watering. No plant (or very few should I say) can survive without water. In the chemical equation for photosynthesis (how plants create energy), water is one of the fundamental ingredients! The best thing I can recommend if you don't want to water your plants is to naturalize them. With a new plant, when it is first planted in the ground it must be babied a bit, but as it becomes accustomed to it's new environment, you can begin to wean it from your care and have it become used to natural waterings from the rain.
Of course, all of this information is a general statement on plants, not to be taken literally for each and every plant out there; Azaleas and hollies respond better to naturalization than annual plants and such. Overall reader, I believe you are going to have to sacrifice something to have a beautiful, healthy plant:
1. No water + full sun = unhappy (unless you're interested in cacti)
2. Water + shade = happy evergreen flowering plant
To those in other areas, I would love to hear whether your flowering evergreens are any different, or if you have any advice on the matter as well!
- Posted from my iPad