Given that the natural environment of urban areas is often so altered and degraded, there is arguably little rationale behind being too fixed in our notions of what vegetation community is appropriate for particular locations. Particular communities are recognised as having an aesthetic that is more appreciated than others, which may lead to situations where attempts are made to establish these communities in places where they would not have occurred prior to human settlement, and to undertake various environmental alterations in order to assist this process. Although the wholesale import or export of soil in order to further the establishment of a particular ‘wild’ plant community is arguably ‘un-ecological’, it is a fact of life, one that brings nature and pleasure to a great many people who might not otherwise experience it, and, in some cases, may result in a higher level of biodiversity of both plants and animals.
The choice of habitat selected for restoration in urban and peri-urban areas is arguably a highly anthropocentric one. The public are most appreciative of habitats that are visually pleasing, hence the emphasis in northwest Europe on meadow creation (a seminatural rather than natural habitat) and in much of the US on prairies, itself a semi-natural vegetation (even in states that never had any ‘natural’ prairie). Fortunately, these are habitats that display considerable biodiversity. The ‘deep ecologist’ would probably argue for woodland restoration as the only valid habitat to be restored in many cases. Woodland is, however, generally created by tree planting programmes that pay little or no attention to the ground layer. There is a tendency for new woodland to be treated as glorified forestry, with little regard for the experience of what actually goes on there—a case of not being able to see the trees for the wood. Woodland edge habitats, very rich in biodiversity, have fared a little better, but perhaps largely through default, as the ‘green cement’ of conventional landscape practice is substituted with blocks of native species. The results may increase biodiversity and introduce nature to the city, but could produce better results on both counts if more attention were paid to their structure, species composition and maintenance (Figure 3.3).
In northern Europe, the floras that combine the greatest public appeal, the greatest floral diversity, with a relatively stable long-term prospect, are those of hay meadows and limestone grasslands. Both establish and are maintained most easily on relatively poor soils, or even waste industrial material, making them a financially attractive possibility, and ideal for urban situations.
Criticism is sometimes heard that the use of seed mixtures over large areas can result in a certain uniformity with species more or less randomly, with little of the ebb and flow of species that gives wild grasslands much of their character (Kendle 2001). Such randomness may also cause more competitive species to suppress less-competitive ones, as was found by Tregay in randomly-planted woodland. However, Julie Toll, one of Britain’s most high-profile garden designers, who makes considerable use of native meadows, does not think this is a problem, believing that ‘nature eventually sorts itself out’, with species finding their own microhabitats over time, although she sometimes enhances particular areas with plugs of particular species, often those combine decorative value with slow germination, for example Primula veris (Toll 2001).
Fertile woodland-edge situations using largely natives of Central Europe can be very effective in early summer and, if competitive species are used, there is little management beyond a late summer mowing—
Alchemilla mollis, Geranium pretense, a Symphytum spp. and Ranunculus acris ‘Flore Pleno’ in the Westpark (June)
Sculpting the landscape with native plant communities
Another approach to enhancing visual appeal operates on a large scale, and essentially contrasts the closed and opaque nature of woody planting against the openness of grass/forb communities, such as the meadow or prairie. The landscape is shaped by using plant communities to guide the eyes and legs (or even wheels) of the human user through it, and so to help contribute layers of meaning to the landscape. It is not surprising that
psychological theories of landscape have had a role to play in the development of many practitioners’ work in this area.
It is, of course, possible to sculpt landscape very successfully from a visual point of view by using remarkably few species. ‘Capability’ Brown did so in the eighteenth century, with far-reaching consequences for landscape art. Yet his landscapes were an idealisation and a pastiche relying on a few tree species, the occasional lake and much grazed grassland. The ecology of a Brownian landscape can be very poor and still look lovely. The same can be said of much modern landscaping; trees and grass can be pleasing, but ecologically impoverished, lacking both biodiversity and the zones of transition that are a vital part of a genuinely living landscape. Thus, ecological design practice would aim to include these vital (in both meanings of the word) elements.
Of the large number of people and practices currently working with native plants in the US, it is those who have most clearly understood the human role in the wider landscape who have made the most impact on the market and on their peers. Darrel Morrison, Professor of the School of Environmental Design at the University of Georgia, who also works as a freelance consultant, is an example. For him ‘each design should reflect and reveal the local landscape character’ so that regional diversity should be celebrated (Morrison 2001). Building on the work of Jens Jensen, Morrison stresses how native plant communities must be used in ways that have meaning for people, for example he states that ‘a central theme is that the overall spatial composition has spaces that move like rivers’ which allow the viewer to position themselves meaningfully in the landscape. However, he sees conventional landscape practice as being ‘extremely oversimplified’ and that ‘plant distribution must have some relationship to natural distribution patterns’. He regards the key to his own design work as being ‘the weaving drift’ where a group of plants of one species trails off at the edges, blurring with a group of the next (Morrison 2001). Morrison points out that the complexities begin at ground level, as different light intensities in the shade of the trees result in a complex of different species-mixes in the grass and forb layer. Savannah, then, offers both the clear visual articulation that human users like and feel happy with, and the rich possibilities for biodiversity. For him, layering, the vertical distribution of plants’, which produces plantings that are not only visually rich but, through creating a variety of habitats, can support a wealth of wildlife, is a key element (Morrison 2001) (Figure 3.4).
In Europe, German landscape architect Hans Luz, has developed the concept of ‘stops’ (Stationenkonzept), a strategy that can help give meaning to a wide variety of different landscapes. The idea is ‘to create intensive designs at consciously chosen spots within larger, extensively designed spaces’. These extensively designed areas may well be areas of semi-natural vegetation. Depending upon the context, Luz sees the ‘stops’ including traditional landscape elements such as dry-stone walls, arbours, sculptures or more intensive planting (Luz 1996). Native plant communities have a vital role to play in the creation of zones of transition between ‘nature’ and ‘culture’. It is standard practice for more formal garden or landscape areas to be near buildings and wilder ones to be further away. Long grass or wildflower meadow/prairie are both highly effective at blurring the boundaries between cultivation and rural landscapes, whilst woodland is even more so.
Ecological design principles are nearly always linked with ‘organic’ amoeboid shapes, but as Lisa Diedrich, in a discussion of the new Riem landscape park near Munich, points out, ‘the animals in these meadows could not care less whether they are crawling over straight or crooked edges’. With its almost Versailles-like scale and formality, albeit a very contemporary brand of formality, Riem ‘refutes any notion that these (ecological aspirations) can only be satisfied in conjunction with winding paths and amorphous frog ponds’. Areas of meadow, woodland and hedgerow are repeated in strict linear swathes to ‘organise the shapeless Riem gravel plain’ (Diedrich 2002). This could be the first of many formally designed ecological designs.