The next step along the continuum of design activity using native plant species is to incorporate stylised or abstracted versions of native communities as design elements. Whilst the design of such groupings is based on the botanical and aesthetic composition of naturally evolving communities, they will usually be abstractions of them, simpler in species composition and smaller in area than the natural models. Yet they will contain the most important species of those communities, ecologically and aesthetically, and distribution patterns which express or even heighten the unique character of those natural communities.
In many cases, this approach presents the potential of featuring more different plant community types on a designated site than would have occurred naturally on the same site prior to its ‘development’. This results from two factors. First, new microclimates may have been created through the disturbances occurring with construction. For example, a previously wooded site may become a partially wooded site as a result of the cutting of some canopy plants, thus creating sunlit openings where the original woodland community species will not survive. Also, the presence of buildings and paved areas creates new micro-environments: a shaded zone on the north face of a building, or hot, dry zones where heat and light are reflected by paving and/or the south and west faces of buildings. Permanent or periodically wet areas may purposely be incorporated to collect stormwater and to let it slowly infiltrate. Furthermore, the human needs and activities introduced to a site may dictate or suggest the inclusion of a greater variety of plant community types than would have occurred there naturally. There may be a goal, for example, of keeping an open view unobstructed. So, instead of reestablishing a multilayered forest throughout the entire site, a low meadow-like community might be designed for the viewing zone. Or, where eye-level screening is a goal, a forest edge community, consisting of Chickasaw plum (Prunus angustifolia), sumac (Rhus spp.) and Eastern red cedar (Juniperus virginiana) might be incorporated.
The abstraction of a native community in a designed landscape may include stylisation in the sense of giving more legible form to the distribution of plants than usually occurs naturally, or incorporating a higher concentration of plants than might normally occur. For example, in a visually prominent entrance area to a building set within a Piedmont forest planting, ground layer plants might be planted at both a higher diversity and higher density than that at which they typically occur in the native forest community. Additionally, the plants may be distributed in a way that heightens their effect, for example in directionally flowing drifts that relate to topographic form or to circulation routes, and/or in combinations that feature particular flower colour combinations. To be true to the community, though, they should be combinations which could logically occur together in the model natural community in the same region.
In some European countries, a further move away from the pure ecological plant community to a more horticultural abstraction has taken place, mainly as a result of a much reduced or depauperate native flora, as discussed in the introduction to this chapter. Whilst vegetation may be based largely upon native vegetation types (such as species – rich hay meadow or coppiced woodland edge), in appropriate settings, additional (nonnative) species from similar habitats may be added, for example, to extend the season of flowering. It should be stressed that such an approach is limited to settings that are clearly cultural, for example urban parks and gardens.
