Thomas Rainer wants to bring ecological planting to the people
Landscape architect Thomas Rainer has a vision of the green city of tomorrow in which plants have important roles to play in facing the challenges of climate change and biodiversity loss. Not plants as individual decorative objects, but as dynamic engineered systems covering rooftops, the sides of buildings and even in drainage ways. He believes that reintroducing the natural world into the urban realm through planting is essential in solving the issues raised by increasing urbanisation.
But rather than simply recreating nature as found in the wild, he is interested in exploring the possibilities of nature as it could be interpreted in these new contexts. “The question is not what grew there in the past,” he explains, “but what will grow there in the future, using design that interprets nature but doesn’t imitate it.” He believes that the time is right for a renaissance in planting design, based on ecological principles, to create self-sustaining systems that relate plants to places, people, and to each other, in ways that achieve beauty, increased biodiversity and lower maintenance.
He also believes that it is landscape architects and garden designers who are best placed to be in the vanguard of these advances. As a landscape architect, he has a vested interest in these matters that drives him to advocate the industry’s involvement. Having worked for several large practices, including prairie pioneers Oehme van Sweden, he recently set up Phyto Studio with fellow landscape architects Melissa Rainer and Claudia West. The studio’s mission is to use new approaches to planting and to disseminate these ideas to the industry and the general public, as the book Planting in a Post-Wild World, co-authored by Rainer and West, demonstrates.
Phyto’s methods draw upon a lineage of ecological planting that includes the work of Cassian Schmidt at Hermannshof botanic garden, James Hitchmough and Nigel Dunnett at the University of Sheffield and German landscape architect Heiner Luz, who have been researching and testing in this area for many years. While inspired by these pioneers, Rainer is aware that their work has not always been accessible to designers and the general public, and aims to express the key principles in a more approachable form.
Large-scale schemes like the meadow at Wolf Trap National Park in Virginia allow visitors to immerse themselves and see how plants actually grow together in communities, as well as providing valuable ecosystem services. Photo: Claudia West
“We are trying to make the most useful parts of those ideas relevant to a broader audience, and to explain why diversity is really important and functional in landscapes. Something other than traditional methods of horticulture can be beautiful, but people seem afraid to try them, so we want to bring to their attention how things could be different and why that’s a good thing.” Fusing design and science, ecological horticulture represents a paradigm shift from ornamental horticulture in the way that plants are used. For designers, it provides exciting opportunities to create adventurous schemes by increasing diversity and thinking about plants, not as individual objects, but as dynamic communities adapted to specific situations.
Key to achieving this is developing an understanding of natural environments through an analysis of their visual and functional characteristics. Looking at relationships in wild plant populations and how they exist in flux, and not as picture perfect states of stable climax, provides valuable insights, which can be translated into designed schemes in order to ensure their resilience and success.
Rainer and West highlight the importance of understanding the key landscape archetypes such as grasslands, woodlands and shrublands, forests and edges, for the characteristics they provide spatially, seasonally and botanically. Within each of these ecosystems, the layering of plants plays an essential role in determining how they function and look, and are always a prime consideration for any designed planting scheme. Filling every niche and creating complete ground cover is essential in ensuring that plants work symbiotically together. Central to this is taking into account the forms of plant structure, foliage shape and root morphologies in order to determine which species can comfortably coexist without over-competing.
Rainer identifies two design layers, and two functional layers. Firstly, structural framework plants that form the visual focus include trees, shrubs, upright grasses and large-leaved perennials such as Andropogon gerardii, Asclepias incarnata, Cercis, Sorghastrum and Veronicastrum, while mid-height seasonal theme plants such as Amsonia, Aster, Hemerocallis, Salvia and Solidago provide colour and texture, often in masses or drifts complementing the former group.
The two functional layers are groundcover plants such as Carex, Geranium and Waldsteinia – low, shade-loving, stress-tolerant species that provide a steadfast basis for any scheme – and filler plants such as Erigeron, Aquilegia and Gaura – ruderal, short-lived species that fill gaps and add seasonal interest. Other important aspects to consider include visual diversity, density, quantities of species, plant behaviour, lifespan, metabolism and competitive traits.
Rainer acknowledges that this is a lot of information to process and that a knowledge gap can act as a barrier to entry. “It is hard, as there are not a lot of shortcuts around plant knowledge and ecological dynamics,” he confesses. Rather than feeling overwhelmed, designers shouldn’t feel ashamed about not knowing a lot about it. He bears witness from personal experience. “We do stuff all the time where we are learning and tweaking. It’s amazing how complex all of this is. We’ve had many failures as well as successes.”
Experience matters, and he believes that the quickest way to get that can be to team with other professionals who specialise in associated disciplines, such as ecologists, entomologists and botanists. While the basics of vertical layering are universal, he believes people need to look at their climatic zones and plant dynamics to determine specific planting palettes. He suggests that the UK maritime climate has a lot of advantages, but planting needs to deal with competitive cool-season grasses and slugs.
A new approach to aftercare is also essential, one that encourages management rather than maintenance. “We are having a lot of conversations with people where we are starting with the minimal amount of maintenance and designing the plantings on that. If you don’t have an understanding of that you can’t have something that will sustainably last. We are trying to design more modular mixes that can survive without a lot of work, systems based on strategy with planting that can be mowed once a year.”
Other important considerations include effective soil preparation and even replacement to support short high forb mixes rather than invasive species. Rainer recognises that this may not be cheap but it keeps maintenance lower so has a longer term cost benefit. This bigger perspective informs his dictum to always “allow management to be the driver of the design”.
The success of these planting ideas requires a degree of support across the horticultural sector, which is something that Phyto is working to establish in the US and beyond. On a more general level, educating the public to the benefits of ecological horticulture and getting the suburban homeowner who doesn’t know what to do with their land more accepting of that look and aesthetic is essential.
Heiner Luz’s planting at Ziegeleipark in Heilbronn, Germany, highlights the creative potential of designing aesthetically driven schemes with an ecological underpinning. Salvia nemerosa ‘Caradonna’, Dianthus carthusianorum and Iris germanica provide early season blooms. Photo: Heiner Luz
Rainer realises that it can be a hard sell convincing people to adopt and accept planting that in their eyes may seem wild and untended. He believes the key responsibility for designers is to ensure that designs are attractive and legible, framed within contexts that people understand and can relate to. “Colour is the ‘gateway drug’ to get to lot of people. As long as you are conscious about framing it well and thinking about off seasons, to make it palatable at its low points, then that makes a big difference,” he says.
As for uptake of these ideas by the profession, Rainer feels that the landscape industry has been receptive and that practitioners who have repressed their love of plants are feeling more liberated now. He realises that designers often feel stuck due to client demands, and that there are still a lot of systemic reasons why traditional plantings persist, but people are getting it and seeing the potential.
“If we can just encourage some people to start gently experimenting, maybe getting away from a design that is pure block planting, with some of the blocks intermingled with other species… if they get a couple of combinations that they are comfortable with, they can understand the dynamics of that combination and start making substitutions, giving them a lot more choices. People get excited if they experiment and it goes well.”
Words: Darryl Moore