Traditional planting schemes set blocks of perennials and shrubs next to one another in order to develop harmonious or contrasting effects that build a picture comprising forms and colours.
The contemporary trend for informal, naturalistic planting schemes uses plants in ways that mimic the natural patterns that occur in native plant communities. Such patterns typically occur over extensive areas and appeal by way of the patterns and rhythms that occur by repetition of a few characteristic species.
In the planting scheme described in my previous post I have repeated blocks of salvias through a matrix of Euphorbia and Sporobolus grasses and here and there a smaller number of Echinacea pallida. Repetition is what gives this combination of just four plant species its visual impact.