need suggestions for south facing wall

i have a new construction home that i'm trying to "beautify" while learning to garden. my current project is the side wall of the house. it's two story and has only one small window on upper right corner of the wall. the house is painted a pale butter yellow. there is a little bit of shade during the day from some cottonwoods and alders that ring the property, but other than that it's full sun, which will be reflected off the yellow wall. the soil is heavy, rocky, partly clay, and neutral to very slightly acid (i usually amend by mixing in compost and chicken manure). the yard is still settling from the construction, so it tends to hold water more than i'd like. i'm in northwestern WA, Zone 8, lots of rain.
i'm trying to decide what to plant that will thrive in the reflected sunlight, look good (contrast) against the yellow wall, and provide interest in a variety of heights and shapes.
so far, i think i want either some smokebush or barberry, because i think the purple will look beautiful against the yellow. this may be the focal point, unless i can think of something else (maybe the garnet shrub type Japanese maple i see so often). i'm also thinking that some variety of blue spruce will look good and add interesting texture.
but other than that, i'm really stumped. any suggestions on plants or the arrangement of such? this is the first thing you see when you turn down my driveway, so i really want it to look good. i'm leaning towards shrubs and small trees, as i want it to look good in all seasons and be fairly low maintenance.
i have yoshino cherries and thundercloud plums lining the driveway if that makes any difference (with lilacs, azaleas and rhodies behind them in the yard, their colors are primarily purple-reds and whites).
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