As many of those who have worked with me know, I most often times will plant in mass either with color and or textures, for both shrubs as well as perennials.
Miquel Urquijo Rubio's gardens are a good example of this. Just as you would use colors opposite each other on the color wheel with interiors, planting outdoors using this same principal creates the same strong visual.
Here shades of lavender and purple are planted with yellow greens to create a strong plant pallet
Always a winning combination for both indoors and out lavenders, gray's and yellow grreens