It is important to add to local biodiversity when we create gardens, whether publicly or privately. Native planting is often considered best, however some exotics provide additional food for birds and insects beyond the local season.
Habitat creation is easily done with a little thought as to types of plants, their arrangement, what is in the neighbouring area (wildlife corridors), and maintenance regime. Variety is important. However, equally important is the need to ensure a harmonious design, where textures, colours form and shape blend well with each other.