NOTE: This article was first written in 2006, so some aspects have been updated to reflect current realities.
Biomembranes is a term I’m borrowing from biology (the structure bounding a cell) to describe the outer skin of future self-sustaining buildings. I have stated elsewhere that I believe that for the built environment – and therefore our societies – to become sustainable, every building and community must deal with its own wastes, generate its own energy and provide nourishment – both physical and emotional – for the occupiers. Only by the creation of truly independant, carbon neutral buildings can we achieve this.
This would be a subtle and far reaching art, not easy to achieve but I believe that the rewards would be many, not to mention necessary. In this respect, the science of biomimicry will play an important part, for example, in developing paint-on polymers that photosynthesize energy, or tensioned fabric five times stronger than steel or kelvar, made with no heat or pollution, just like a spider’s thread. Whilst we haven’t perfected those products yet, let me list some of the benefits we can look to achieve in the near future:
horizontal and vertical skins of living plants that insulate, filter the air of dust and pollution, dampen noise and attract wildlife. Current living walls are used sparingly as art pieces.
composting and filtration systems that clean the building’s waste and return nutrients and water to the biomembrane and surrounding landscape.
Algal biofuel production using building wastes.
interior landscapes that provide internal cleansing and beauty.
blurring of internal/external space.
energy generation as integral with the building fabric as passive solar/pv/wind.
pedestrianised streets as wooded valleys or urban forest gardens.
SUDS drainage to filter excess water straight back to the local water table.
pedestrian/bike/electric vehicle shared surfaces removing car domination.
increase of social space by good design.
Some of these ideas are becoming well established, such as green (or living) roofs and walls, others are being played with by a few, but as yet, no one is trying to pull all these things together into a cohesive whole system. I am thinking of concepts such as combining vertical greening with greywater filtration, active cooling systems, air purification and algal biofuel from building wastes. I have recently been inspired by the work of the world-renowned architect Ken Yeang (Llewelyn Davies Yeang) based in London and Malaysia. Ken has worked extensively on the concepts of bio-climatic buildings and so his ideas are very close to my heart. Furthermore, one of his main concerns is the organisation of internal space by social structure, rather than by economic return on investment. This very much reminds me of the work of Christopher Alexander (see Pattern Language); despite apparent differences of style, the underlying philosophy is similar, Ken’s work placing it into a modern urban context.
There is a lot to do but the future will need autonomous
bio-buildings that take care of themselves without external input, other
than sunlight and human organisation. The main challenge is then to
retrofit these systems to existing buildings, which will always be the
large majority of available building stock.
Meanwhile, take inspiration from the work of Hundertwasser (top right) and Ken Yeang (bottom right). The application of green technology, biological water filtration and the use of every surface to create living, breathing buildings shows that humanity can and will grow up and see beyond the profit line, which so dominates and limits current thinking.
The way in which we design, create, maintain and use urban landscapes is likely to change radically in the next 15 years (in fact, modern society is in for overwhelming change). Urbanisation, climate change and the rapid rise of technology and artificial intelligence (AI) will see to that. Don’t think that the rate of change will be the same as has occurred in the previous 15 years, for technological growth is on an exponential growth curve, not a linear one. Cities and systems are becoming smart, connected to the Internet of Things and that is just for starters. So how will this change the way we design and use our urban landscapes?
Firstly, we know that there is huge movement of populations from rural to urban life, especially in the developing worlds and most markedly in Asia. This creates huge pressure for new urban infrastructure and this is not always well planned growth, especially in terms of forward thinking to account for future changes. Nonetheless, it is happening and happening fast. The UN expects 66% of the world’s population to be urban by 2050, by which time there will be 9bn of us – so 6bn in cities. Mega-cities have to grow in a way that sustains huge numbers of people.
Secondly, climate change is also occurring at exponential rates, raising the difficulties of living in any environment but with especial problems for mega cities, most of which are in coastal regions and subject to rising sea levels and worsening weather patterns. Cities are hotter than the surrounding land due to the nature of materials used, whilst heavy rainfall brings flash-flooding. In arid countries, built environments are in danger of becoming too hot for humans to inhabit. Cities will have to take on these challenges, generating micro-climate.
Thirdly, technological change is happening exponentially and this will impact what we do, how we live, how – if – we work and how we tackle the above problems. Some view the challenges and changes with fear, thinking they will only exacerbate problems. They could do, anything can be mismanaged (such as a planet) for example. I foresee that technology is actually the only way we are going to get ourselves out of the mess we have created, the only thing that can act on the vast scale needed to re-balance an out-of-kilter Gaia.
When we take these three factors into account, we can see that the future of urban landscapes has to be so much more than the addition of the odd pocket-park here and there. Landscapes have to mitigate the environmental factors, make huge mega-cities liveable for a population increasingly disconnected from nature and provide meaningful lives in an era when many of us may not work in the way we are used to.
Weedy and neglected landscape plantings are all too common. No-one wants to pay for maintenance
How will cities become smart and use this to better the environment? If we are looking to increase the amount of urban landscaping significantly, then the first issue to tackle is cost of maintenance. No one wants to pay for maintenance and often, no one does. How many planted landscapes do you see smothered in weeds, wrecking or negating the designed purpose? Or municipal plantings and car-parks where plants inevitably die and are never replaced, leaving huge gaps. Shrubs hedge trimmed into amorphous shapes because that’s the quickest way to “maintain” them. It’s a poor standard and it’s all we’re going to get – no-one is going to pay for trained horticulturalists to do something better.
Landscape lobotomy: maintenance is the quickest, cheapest possible
Yet there is an interesting possibility – automation is likely to remove nearly 50% of jobs in the next decade, especially low-skilled or repetitive ones. In the landscape trade, there are already semi-autonomous strimmers and grass-cutters on the market, how long before we have horticultural robots maintaining our landscapes? All the technology is already here, prices are falling and an uplink to an AI would identify every weed known, give the correct procedures, know how and when to prune every plant in common cultivation. Robots would work long hours without tea breaks! If basic maintenance getters a lot cheaper, we can have more landscape and such robots would be cheaper, eventually. Living walls would be a prime candidate, with a simple maintenance cradle (much like a 3D printer head) that crosses the wall with a maintenance bot on it. I’ve seen so many potential living wall projects fall at the maintenance-cost hurdle. In such a scenario, displaced maintenance crew can retrain as bot-supervisors or true horticulturalist for private clients.
Horticultural robots will make maintenance cheaper and more effective.
We’re going to have to do more than just make maintenance affordable; rather, that is the factor that releases the possibility to do more urban landscaping. Many of the elements we need to put in place are already in existence and being used, but we need to join the dots and think holistically. For example, green roofs are seen as a separate trade from green (I prefer living) walls. Instead, we need to be talking of biological membranes (biomembranes) for buildings, a whole-system concept, where the living skin regulates the internal environment, filters pollution in both directions, dealing with generation of energy, cooling, clean air and water. Living walls that currently use potable water for irrigation when they could be cleaning up the used greywater that all buildings generate is another example.
Building Biomembranes regulate building ecology and create vertical landscapes
Systems that provide services that are of consequence to the functioning of a building, street, or neighbourhood need careful management and control, much of which will become automated. In just the last year, for example, new irrigation controllers have come on the market which not only are connected to you via internet, they also connect to the nearest weather station and adjust their regime according to the conditions. I use these for living walls; I do not advocate any irrigation for horizontal landscapes in temperate climates. But things will move beyond this, with AI monitoring ground moisture levels and moving harvested rainwater from one holding system out to another part of the city where it is needed. And urban farming – especially vertical – will be a large part of mega-city greening, although it might not be on display. Sophisticated hydroponic systems are springing up in warehouses and roof-top polytunnels all over. Such food can and should be organic, local, healthy, nutritious.
A smartly connected landscape means we can maximize the benefit it gives to the people who live, work or pass through it. With the majority of people living in urban mega cities, we have to create an environment that is fit for ultra-dense urban living. As these metropolis’ grow, people will have less and less daily contact with Nature, which is not good for our deeper wellbeing. Biophilia is our innate need for contact with the natural world: plants, trees, flowers, insects, sunlight, water, earth. A concrete jungle is not a substitute for the real thing but we mostly won’t have time to “get out there” and experience wild Nature.
I think inner city pollution will blow over – excuse the pun- in the next 5-10 years as we start a massive switch over to electric transport, most of it driverless. In fact, drone taxis are already under development and as buildings and living habitats reach skyward we can expect the landscape to move with them. It will become commonplace to have high-level dronepads – even private ones. Some people might not even go down to the ground much! So landscapes and biophilia must come to them. Fortunately, there is a rash of building-integrated vegetation going on and I see this trend increasing. Incidentally, if you wanted more good reasons for using bots to maintain planting, imagine working on living walls or trees that are 50 stories up!
As for the wider environment and the looming crisis of climate change, I can only hope that emerging nanotechnologies give us the tools to clean up our act and neutralise the positive feedback loops we are creating. Scientists are already working on nanotechnologies which capture and convert carbon into useful materials and one day such microscopic machines may roam our land and seas, removing plastics and other dangerous waste. If this is done at a molecular level, we turn problems into resources. We’ll be printing our houses (already being tested) compounds made from waste materials but without the current worries of using say, bricks made from recycled plastic which off-gas VOCs. We can only hope these technologies emerge before it’s too late to save the climate in a state that we can survive in.
So the next 10-15 years are going to see change at an unprecedented rate and it may not all be a smooth ride. I am excited by it however and think that there is much to be done to ensure that we create new urban environments worthy of habitation and that we take care of all environments and indeed the whole planet. Smart cities are coming and at their best they could loosen our imaginations and liberate us from a monotonous life of work and stress. Let’s make that the scenario that happens…
We are now a decade into the explosion of living or green walls. There have been many successes and some notable failures along the way, some of of which may be system-induced and some caused by inadequate or inappropriate maintenance regimes. Assuming we now have systems that work at least reasonably well, what is required by way of maintenance to keep walls looking good?
First of all, we have to acknowledge it is the large, commercial projects which get the attention and sit within the public eye. If anything goes wrong with these, it is noticed, big time. Commercial walls, I have found, are governed by financial pressures and that can sometimes mean that over time, budgets are cut and maintenance regimes compromised. When maintenance goes out to commercial tender, it is usually the cheapest price that wins.
Secondly, we have to understand that there is a profound difference in the way we perceive vertical landscapes from horizontal ones. With ordinary planting beds, we would plant probably between five and nine groundcover plants per m². Living walls are planted at between 30 and 100 plants per m², a highly artificial and crowded environment. Yes, we are treating these as groundcover which knits together, but unlike horizontal beds, gaps between plants are not deemed acceptable. It is also harder for plants to spread or fill in laterally, depending upon the system they are planted into. Visually, when you look at a living wall, you look straight on at eye-level, then upwards. So the lower sections of walls can come under intense scrutiny. Any failures have to be replaced and the rate is higher than that of horizontal planting, for the aesthetic reasons just stated.
Thirdly, living walls depend upon the right plants being chosen; they have to have the right characteristics of habit, growth and longevity. Some common garden plants are notoriously temperamental, short-lived or subject to pests such as the notorious Vine Weevil (which seems to attack an ever-increasing variety of plants). As a designer, I have previously used many plants that I don’t use now, and I find the list is shrinking, as you learn about a plant’s ruggedness over time. We are still pioneering a new methodology and now I’d rather use a smaller palette and feel more confident about it’s long-term success.
Fourthly, finally and perhaps of greatest importance, is the maintenance given to a living wall. I prefer the term living wall to green wall, because it reminds us that they are just that, living. They are also put into an extremely hostile and unnatural location and aspect. Sometimes those who look after them don’t do a good enough job. Many commercial landscapers are not horticulturalists and don’t really know that much about plants. That may sound shocking (and I’m pointing fingers at no-one, for this is just they way things are) but a Kew or RHS trained gardener is unlikely to be employed in a commercial company. Even knowing what to do for the best health of a plant on the ground could be inappropriate if done to the same plant on the vertical.
The pics above show living walls in three different systems, all in poor condition (including one using my older system); I’m not saying where or who because blaming is not appropriate nor my intention; rather, awareness raising is. The fact is that each and every system out there has good and bad examples to show. It is interesting to note that training efforts have been begun in at least one university, but this type of knowledge is a hands-on, college affair. Right now, it is only learnt on the job and this is art of the problem; many operatives simply don’t know their plants. If you don’t know the name, you’re not going to know anything about how it grows or when and how you should prune it.
My answer (and this goes much against my designer instincts) is to restrict the planting palette to those most able to survive. I always want to use more varieties, but it is sobering when you see them dying because they can’t cope with the conditions, or falling off the wall because the roots have been eaten by Vine weevil or millipedes. Beautiful grasses that have high levels of old, straw-like debris among the new healthy leaves are a no-no and geraniums may or may not look good in the winter months; such plants must be used with care. Patterned designs seem to fall by the wayside too; bold swathes are fine until one species fails and dies back, then you are left with a gaping wound.
So you may be thinking, should we do this at all? My answer is an emphatic yes, we should and must. We need to green the vertical in cities, for it is often the only space left available. We have all the needs of biodiversity, pollution mitigation and biophilia to account for and living walls provide those where no other greening method can – not even trees. We still have much to learn however, and the skill of maintenance has to be appreciated more by all involved. In fact it needs to be venerated and it’s practitioners respected and paid more.
Systems, at best second or third generation, need to evolve and be better understood. Or rather, plants need to be understood more, and their optimal needs met. We have, as I keep saying, hardly scratched the surface of what is possible and of what needs yet to be done. We need to learn more, try more and expect more.
There is something incredibly exciting about living walls. Stacking green plants on the vertical plane on buildings, where you’d think they just should not be, goes against the odds. Yet nowadays they are almost commonplace, and most people have encountered one somewhere. They cling to life with extraordinary tenacity, usually in a growing medium only a few centimeters thick, with water fed via irrigation pipes. Cynics may criticize and some walls are without doubt better designed and maintained, or use a better system than others, but we should applaud this urban green trend, and encourage it. We need it. Modern systems are reliable and use very little water or energy to run.
As a global society we are going through unprecedented changes; now more than 50% of the world’s population is urbanised and this will grow to 75-80% by 2050. Most of those people are essentially disconnected from Nature. It is now recognised that we have an innate need, called biophilia, to maintain our relationship with Nature. Not surprising really, when you think how we have evolved, yet the psychological and physical cut-off, over the last 100 years, has been astonishing. This can only become more pronounced as cities continue to swell, and highly-stressed people produce dysfunctional societies. If we can green our urban streets then perhaps we can counter this negative effect. Green walls take up almost no footprint in the urban landscape, not even a pavement width. All that is needed is a supporting wall and we have plenty of those. Trees are beautiful and add huge amounts of biophilic interaction into a citiscape, but we find them increasingly difficult to site, due to underground services and growing space needed. Those of you who read my blog will know that I also consult on trees, so I love them dearly, but I see living walls as having a different role to play and as being more versatile.
Living Wall in a small courtyard garden by Vertology
Living walls have physical benefits on the environment too. They provide a haven and food source for insects, especially bees. Birds find seeds, berries and of course, insects on the wall and smaller birds are known to nest amongst the foliage. Living walls are also helpful in mitigation of air pollution; I was involved with designing and plant selection for a wall put up by Transport for London (top picture) to test the ability of plants to capture pm10 – airborne particulates, primarily from diesel engines. Whilst we need to remove the source of these pollutants, capturing them is a good secondary strategy. It turns out that walls in a street canyon (where the building height is greater than the street width) cause the air to move in a cyclical manner, so air passes through the foliage of a living wall several times. Trees can do this, but dense canopies can actually trap particulates down at street level, concentrating them where people are. Most trees also are deciduous, so have no such benefits in the winter months.
Interior Living wall in Norway, installed by a Vertology partner
We can bring living walls into the interior, and in fact in hostile climates, that’s where you’ll find most of them. Whilst I have designed outdoor walls in climates as diverse as Dubai, Norway (Trondheim, 62° latitude) and Chicago, in such places it is often easier to put your dose of biophilia indoors! We spend 80-90% of our time inside, so this makes sense. Such walls also clean the air. Much quoted studies by NASA have shown that a range of common houseplants (which are basically plants of a sub-tropical origin) are efficient at removing Volatile Organic Compounds VOCs, such as formaldehyde) from the air. These can be found in concentrations far higher than outdoors, due to the nature of air recirculation and energy conservation. So we bring the jungle indoors, where we live and work.
Walls have the most drama when they are large, but they don’t have to be. Small walls in intimate spaces still have a large impact. This can be a home, courtyard, rooftop or office reception. Small is beautiful.
A small indoor living wall by Vertology
Having worked extensively with living walls over the last decade, I now consult, design and install them worldwide via my company Vertology Living Walls, and its approved partners. Grab yourself some biophilia – install a living wall!
The Walkie-Talkie building, infamous for melting cars, has one of the UK’s largest green walls, to the South side of the building, facing North. I designed this wall as my last commission for Biotecture, the living wall company I conceived and co-founded. They were in turn commissioned by Willerby Landscapes.
Early Sketch of layout
The final layout and planting plan
The design went through many permutations but in principal I wanted to use the wall size to create a banded horizontal wave pattern, each band consisting of a matrix of similar plant types. Some smaller areas of single-species plants were also included as these would be better defined by the contrast.
A detail of the wall living wall design to 20 Fenchurch Street, by MLD
Plants were chosen with a wide mix of Natives – at least 12 species – 9 groups of the aforementioned matrix planting and a number of single species groups and clumps, such as Luzula sylvatica (native woodrush) or Polystichum aculaetum (hard shield fern).
The lower bands were much smaller than the upper bands, to give the best visual aspect to those at street level and to bring things to a human scale. The layout design was simple, the plant groupings and textural contrasts more complex. Time will tell if they work out as planned!
Installation seems to be happening in stages, as the building works complete. the photo below was taken in July.
Fenchurch Street Living Wall being installed July 2014
Is there a “next place to go” for green/living walls? Absolutely there is – there’s probably two next places to go – in opposite directions, seemingly. First we have a growing need for the mitigation of environmental factors which are largely of our own making; air pollution, rising temperatures, storm and waste water management and purification. Methods of providing ecosystem services, if you like. We need these in urban areas, right at the heart of where the problems originate or concentrate. Linear, end-of-pipe solutions to things such as “waste” water (how can H20 ever be waste?) are becoming increasingly unaffordable, especially in third-world regions where the real population growth is taking place. So we need cyclical systems to deliver on-site solutions.
Global levels of air pollution. London looks good here, yet still fails WHO limits
Such systems must be cheap and effective. They will look green, be alive, but not driven by aesthetics, although that is not to say they won’t look good. But we need these types of wall to be installed an a huge scale, if they are to make a genuine contribution; with the climate changing so rapidly, we need all the help we can give ourselves. I’m working on such a system now, focusing on air pollution mitigation.
Vertical greening is particularly effective in the urban environment for two reasons: we have very little open space to implement large-scale greening on, and the effects of pollution are most felt in the urban canyon – where the sides of the streets (buildings) equal or exceed the width.. Greening the sides of urban canyons, therefore, has the greatest potential for capturing particulates (pm10 is the range causing most concern).
It is interesting to note that trees are often cited as being good at removal of dust and particulates – but green walls are far better. For a start, most urban trees are deciduous, so they only have leaves for seven months of the year, then there is the recently researched fact that trees in an urban canyon can actually trap particulates under their canopy, preventing the natural air movement from mixing pm10 into the larger air volumes. I work with trees and love them, so have no bias in this; we just need to understand the interactions between air movement and greening. So this for me, is the next generation of vertical greening technology. Interestingly, being next-gen doesn’t mean being more high tech. Given that things have to be cheaper, they have to be low tech but more effective. This is where understanding the effect of things is crucial.
The street canyon is the best place for vertical greening to remove air pollution.
I said that vertical greening developments would move in two directions; the other is for increased human interaction, for biophilia. As 80% of the world’s population will be urban by 2050, many of the projected nine billion will have little access to nature. We need to make our cities green forests – not the urban jungles they have become. Every building needs to have vertical parks and gardens built in as standard, giving us direct contact with nature (whilst at the same time giving us all those ecosystem services I mentioned earlier), which brings the two directions (function vs beauty) right back into one place. Furthermore, such systems must be easily retrofit-able onto existing building stock.
Vertical “biomembranes” give us vertical landscapes, satisfy our love for nature – biophilia and deliver ecosystem services
So there is a huge role for vertical greening to play for humanity, keeping us in a functioning, livable environment, giving us beauty, satisfying our need for biophilia and keeping us sane in an urbanised world. We’ve barely scratched the surface of what we can do and I’m certainly looking forward to upping my game with new products that take is in the right direction.
I recently visited newly installed walls at Wilson Street, London, which I designed for Biotecture.These were a joy to behold with lush new growth on the two main walls on the ground floor reception, and later walls to basement areas which were designed and planted up slightly later.
I launched my newsletter this week on vertical greening, sending it out to clients and those who’d signed up here or on the website. From the number of views and feedback, (considerably higher than industry standards) I’d say it was a success! The aim is to inform interested parties of news and developments in the field of vertical greening.
Don’t miss the next issue – sign up using the form on the right!
I’ve been reading several websites by visionary developers in Azerbaijan, who are proposing some massive Dubai-style developments to the Bay area of Baku, the country’s capital. One, the http://khazarislands.com/ seems like an ambitious Dubai-competitor, an ultra-sleek development on up to 30 artificial islands (think the Palm Jumeirah), the other is based on an existing island and whilst just as pretentious, http://www.ziraisland.com/ at least aims to generate all its own energy from renewables, and to be carbon-neutral.
The buildings are all based on the forms of nine iconic mountains in the Caucasus Range. Actually, not a bad idea from the point of view of seismic safety and thermal efficiency etc. Serious plans to make a huge modern metropolis that is self-sufficient are rare, with perhaps only the Chinese actually trying this with some of their Eco-Cities.
What is needed is to develop a coherent urban greening policy to integrate technologies like living walls and urban tree planting and care, with a carefully thought out irrigation policy. People still don’t see how essential green walls will be in integrating ecosystem services into a buildings basic functionality, but it will come. Let’s watch with interest.