See Nigel Dunnett’s Naturalistic Planting Philosophy:

Nigel Dunnett is Professor of Planting Design and Urban Horticulture in the Department of Landscape Architecture at the University of Sheffield, Innovative approaches to planting design.  Plantsman, designer and pioneer of the new ecological approach to planting gardens and public spaces.  Integration of ecology and horticulture to achieve low-input, high-impact landscapes. Nigel promotes the need for planting in public areas to such that people can be immersed in surroundings of textures, colours, movement and wildlife.