Article by Tobias Arends
In a highly globalised world in which international trade and its liberalisation is at its height, we as planners and landscape architects are also noticing the consequences of this. The large supply and sufficiency of different materials and plants on a small scale, together with the different philosophies about the design of public space on a large scale, has placed many designers - provided the budget is sufficient - in a luxury position. A luxury position that we should be critical of, because is the abundance of possibilities really that good?
The availability of plants has also increased, but partly because of this opulence, there is also praise for projects that return to the basics and leave the extravagance of the exotic behind. It's as if they've reinvented the wheel. For example, the latest design by Lageschaar Vaste Planten for the Floriade in 2022, entitled 'Wild at Heart', uses exclusively native and conventional perennials and was therefore called 'new' and 'innovative' by several authors. In a way, that's true, because everyone has access to an abundance of opportunities, the indigenous is unfortunately often overlooked. And that while it is precisely the indigenous that can offer so many solutions to the current climate problems.
'Wild at Heart' in the Floriade (source: Stad+Groen)
With the current challenges in spatial planning, it is important to pay attention to all McHargian layers, soil and water are an important part of this. Soil and water have traditionally been leading for everything we do as humans in public spaces: an agricultural field is not profitable on a swampy clay soil and willows, for example, find it difficult to grow on acidic, nutrient-poor soils. Nowadays we do have the means that broaden our possibilities, spreading fertilizer and lime can create the right growing conditions for example. Partly because of these possibilities, today's designer no longer must limit himself to the facilities offered by the subsurface. Any obstacles that the surface brings can be overcome with the right adjustments.
But these tools also come with drawbacks. In gardens where potting soil must be supplied to create the right growing conditions for the plants, not only is maintenance higher, but the connection with the subsoil is also more difficult to establish. Suppose that the willows from the earlier example must be placed on acidic, nutrient-poor soil. Suitable soil must then be provided so that the tree can survive in this location. By applying this extra layer, the character and values of the underlying soil layers are lost. These soil layers and their relationship with the aboveground are crucial for the functioning of an ecosystem. By applying an extra layer of potting soil, the soil life deteriorates, and, among other things, the formation of mycorrhizae is made more difficult. Examples where this unfortunately still happens are the Floriade and the Keukenhof, where the necessary growing conditions are still created by man in order to create the perfect picture. The picture is certainly beautiful, but also very artificial and anything but natural: there is nothing to be gained here for biodiversity and soil life.
Left: Tulip borders in the Keukenhof (source: Keukenhof)
Right: Chinese garden in the Floriade (source: Almere THIS WEEK)
Fortunately, there has been a trend for years to make the sublayers really leading in the design of public space, so it is rare to see - with a few exceptions - that the connection with these layers is not sought. However, there is still a difference to be made between the use of native plants that fit on the subsoil and exotic species that can grow on the same soil. Native species can grow in an area on their own and have been there for centuries. They bring many benefits, benefits that exotics can't always provide. For example, native plants are already adapted to the environment and therefore require little to no care. The plants have already adapted and can do so again in the process of climate change. Also, many insects are accustomed to and familiar with native plant species. A wide variety of native plant species is good for the above- and below-ground flora and fauna. Finally, the numbers of native plants are declining in the Netherlands, and it is crucial that these species are replanted for the recovery of nature and biodiversity.
The city garden of Kempkensberg in Groningen sets a good example and uses almost exclusively native plants. Exotic plants are also used, but this is mainly in the roof gardens, because exotic plants are better used to these conditions than native ones. There is also no use of artificial fertilizers or pesticides anywhere in the soil. If the plants are well selected, these types of tools are rarely needed.
City garden of Kempkensberg in Groningen (source: Baljon landscape architects)
An example from abroad where native planting is deliberately applied is the 'Indigenous Learning Circle' on the grounds of Curtin University in Perth, Australia. Here, however, it is not biodiversity, but culture that has been taken as the starting point for the choice of plants. With the use of more than 2500 native plants and trees, the designers want to reflect the history and character of the place. The plants used have been in this place for centuries and may often be seen as bewildering and therefore something bad. But this rewilding gives a piece of land back to nature and its flora and fauna while also strengthening our feeling about the place, so this is something good! For many, this idea is also known by the term 'genius loci'.
'Indigenous Learning Circle' on the grounds of Curtin University in Perth (source: UDLA)
Finally, native plants are also used to improve the soil or water quality of an area. In an urban context, De Ceuvel in Amsterdam is a good example of this. In the design of DELVA, native species are used to solve the water pollution in the former shipyard in a nature-friendly way. The surplus of houseboats in the city is temporarily reduced because several of them are given a temporary place here until the soil is clean again and can be used for further purposes.
De Ceuvel in Amsterdam (source: DELVA)
Some of the native plant species used in the Ceuvel (source: DELVA)
Fortunately, there are many more examples of projects that use native plants. My hope is that this movement will continue and that the use of native plant species will soon be the norm again. Let the soil, the water and the indigenous be leading for the design of our public space again and in this way make the world a more beautiful, healthier and more informative place!
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