Clematis can easily be planted with a variety of shrubs and trees. The trick is realizing the eventual size of the shrub and trees you are planting them with and the fact that the plants will compete with the clematis for moisture and nutrients so you will have to be vigilant with giving the clematis extra food and water.

Unless you plant type I or II clematis, they will definitely need to be trimmed each year. If you don't trim type III clematis, they will develop woody trunks over time, the blooms will develop higher on the newer wood that is formed each year, and the plants will lose foliage on the woodier older vines.

Clematis do not need their feet in the shade. They like shaded feet because the shading via mulch helps maintain a more consistent soil moisture level. That being said the plants will naturally grow towards the sun which travels from east to west. Planting the clematis on the east side of the shrubs, if possible, would allow the shrubs to provide afternoon protection from the sun.

In your warmer zones, the type III clematis would probably work better, especially the viticellas since the type IIs tend not to like the heat and humidity in my zone 7a garden here in central NC.

I have planted 3 clems in viburnum shrubs. They don't seem to be the least bit hindered by the shrub and are almost invisible until they bloom. A little vine management helps to space the clematis evenly and spiral it around the shrub to enhance the effect.