In 1938 an American by the name of Stanley Hart White applied for a patent for his vertical garden structure and concept. This was duly granted and nothing more was heard about it, until recently.
The emergence of vertical gardens as landscapes was brought about by growing legislation to control the quality of air in urban areas and so architects started looking for ways to increase greenery in dense urban spaces. The French botanist Patrick Blanc fascinated by how plants survived and adapted to peculiar situations, in particular vertical surfaces, came to the rescue. Blanc’s approach was that plants do not need soil. He claims soil is nothing more than a mechanistic support. He suggested that water and the many minerals dissolved in it, together with light and carbon dioxide to conduct photosynthesis, are the only essential things to plants. Blanc’s assessment was that plants in the wild are growing on vertical surfaces and wherever water is available; in tropical forests, in temperate mountain forests and that the plants can grow on rocks, tree trunks and soil-less slopes. In Malaysia for instance, out of the 8,000 known species about 2,500 are growing without any soil.
Thus if you think of a cliff with plants growing on it; what you have is a vertical structure with a medium where the plants can establish their roots and support themselves while also getting the required nutrients for growth. Therefore the idea of a living wall is nothing more than a wall completely covered in vegetation. Modern day vertical gardens attempt to simulate the same environment and can do this in a number of ways.
One approach is to create large scale rigid structures which are incorporated into the infrastructure of architectural designs. They are used to clad buildings, (both indoors as well as outdoors), along with other landforms such as tunnels, slopes and walls. The majority of systems have evolved from the Blanc hydroponic style, no longer utilising soil as the growing medium, but using layers of inert growing mediums with nutrients provided via irrigation. These gardens are commonly referred to as ‘artificial green walls’.Other variations which utilise soil as a growing medium have emerged and these are typically referred to as ‘natural green walls’. The benefits of soil based vertical gardens is that these types of gardens have a greater impact upon the biodiversity of the environment and allow a greater variety of plant environments to be established, providing natural habitats for both additional flora and fauna.
This form of urban gardening is often designed as an art form to decorate buildings in cities and has been hailed as one way to make cities more enjoyable, healthier and ultimately greener places. From this a new science has emerged on how humans need nature to be healthy and happy. Biophilia is the term which literally means ‘love of life or living systems.’ It was first used by Erich Fromm to describe a psychological orientation of being attracted to all that is alive and vital. Edward O. Wilson, the American biologist, introduced and popularized the biophilia hypothesis in his book, Biophilia (1984), where he defines biophilia as “the urge to affiliate with other forms of life”. The hypothesis suggests that there is an instinctive bond between human beings and other living systems. He proposed the possibility that the deep affiliations humans have with other life forms and nature as a whole are rooted in our biology. Research into this area is providing some interesting findings correlating human health with a proximity to nature. Studies shows the emotional and psychological benefits of nature is mounting and can result in reduced stress, improved recovery from illness, enhancement of cognitive skills and academic performance, assistance in moderating the effects of ADHD, autism and other childhood illnesses. All these values are in addition to the immense economic value of the ecological services provided by natural systems.
Hanging Gardens recognizes the need for biophilic workplaces, for healing gardens in hospitals, for homes and apartments that provide abundant daylight, natural ventilation, plants and greenery. However less attention has been focused on the city or urban scale, despite the fact that the planet continues an inexorable trend in the direction of urbanization. The agenda is one that must extend beyond conventional urban parks and beyond building-centric green design. It is about redefining the very essence of cities as places of wild and restorative nature, from rooftops to roadways to river fronts. It is about understanding cities as places that already harbour much nature and places that can become, through bold vision and persistent practice, even greener and richer in the nature they contain. These factors have stimulated urban design and modern architecture to focus an increasing amount of attention on these areas to ensure that the quality of life is maintained in urban areas. As a result vertical spaces are being viewed with new interest and ‘living walls’ and ‘vertical gardens’ have become generic terms for these types of spaces.
On the broader scale, health and climate change concerns are driving increasing amounts of legislation regarding the quality of the environment. According to Tim Flannery in his book ‘Here on Earth’, CO2 levels peaked naturally about ten thousand years ago around 265 parts per million. CO2 slowly began to increaseand around 1800 it stood at 280 parts per million. It is suggested that this rise was due to the growth in agriculture, in particular rice production. Over the past 200 years, humans have increased the CO2 in the atmosphere by a whopping 30%. The excess has come from two sources, 40% from the destruction of forests and the rest from burning fossil fuels. James Lovelock believes that 9 out of every 10 of us living in this century will die from climate impacts, leaving a population clinging in refuges in places such as Greenland and New Zealand. If we could reverse the deforestation trend and by 2050 restore between 8 and 17 percent of what we have destroyed, then between forty billion and two hundred billion tonnes of CO2 could be captured in the growing rainforest.
It is sometimes claimed that if humanity became extinct the earth would look after itself. That may be true in the very long term, but in the shorter term disaster would befall many species and ecosystems. That is because theyhave been so deeply compromised and only human efforts keep them functioning properly. The Australian Wildlife Conservancy, along with the Aboriginal land holders, keep dozens of species from extinction. In New Zealand and many other islands, species are kept in existence only through the most careful protection from introduced pests. Even in the UK, active management is required to preserve species. As the pace of climate change increases and as urbanisation intensifies, to the point where for the first time in human history, more people live in urban areas than in the rural environment, our efforts to protect nature will become more critical.
What makes the emergence of vertical gardens so interesting, is that gardens were originally used as mediators between the rural an urban environments where there was once the city and then the garden. This concept changed in 1857, when Olmstead led the movement, with his plan for Central Park to have the garden in the city. The garden was seen as the solution to the ills of the unhealthy industrial city.
In the second half of the 20th century Ian McHarg started the rise of the landscape ecology movement. This led to the concept of the garden as the city and placed the landscape at the forefront of future cities. This reliance ona beneficent ecology to control human activity fell short of improving human interactions. Cities require density and a legible civic purpose. Diminishing natural resources, rapid climate change, energy efficiency and population growth are delivering compelling economic arguments for dense forms of urban development. So now we are back to the garden in the city. As a result, the designed landscape, ecology, urban planning and the architectural form are now equal partners in the making of a city as part of the larger strategy of urban, environmental, economic and social regeneration.
Within the urban fabric, designed landscapes must now mediate between the urban architecture and the larger landscaped ecological infrastructure and this must be an imaginative, sustaining and biophysical intervention to rejuvenate the urban culture with the idea of nature.
Vertical gardens have a significant role in the dense urban environments to bring gardens back into the city, as Olmstead advocated way back in the mid 1800’s. Vertical surfaces of buildings are part of the public realm and provide vast amounts of square metres that cannot be used by other disciplines, except art. These spaces must be maximised to manage water runoff, urban temperatures, noise, insulation, air quality and of course aesthetically, to bring the much needed garden back into the city for the preservation of biodiversity as well as for human wellbeing.