Even evergreens shed leaves,they just don't do it all at once in the autumn so you'll have a bit of leaf fall to deal with whatever you plant.

There are some attractive evergreen cotoneasters with flowers in spring and berries in autumn

I like this one

Cotoneaster conspicuus x C. dammeri.

http://www.flickr.com/photos/31559373@N00/3554081853/

The dreaded clematis armandii? Years later people will say, 'There used to be a gravel garden here, but it's long been grown over'(!) What about trachelospermum jasminoides for late summer scent?