My first thought was: cool. I think that sounds like such a good idea. I thought of barberry rose glow with golden varegated japanese grass. I won't try to spell it now, too early to look it up. Something like Hakenola Macro something Aureu somethng. (I'm a big help, eh. maybe i'll just go back to bed), Anyway your combo sounds nice.

JUst to add something to this old message, the silver mound will look good, but it can quickly grow quite large if given enough water. so dont plant them too closely. Maybe two feet and then plan to prune them back when needed.

The barberry isn't a dwarf either. Plant each kind in drifts made up of all one kind, with enough space between the drifts to make sure there are no conflicts. Viewed from out in front the artemisia will appear to be nearer the barberries than it actually is.

Probably need to frame this with some evergreen shrubs to provide yearround appeal.