I was working in AECOM’s Design and Planning section in London in 2008 when I was approached by colleagues looking for ways of improving the design of the southern terrace. A barrier was required to separate residential properties on Bulwer Street from what was expected to become a noisy and crowded entrance to the new Westfield Shopping Centre. I had recently visited various living wall projects in France and immediately saw that this was an opportunity do something similar in London.

View of Westfield Green Wall - Photo Courtesy of Aecom

The inspiration for the north facing part of the wall was the shady banks that you see around my home town Axminster, in Devon. Ferns dominate and make these features green year round but woodland wildflowers bring seasonal interest.  I selected the a modular living wall system because it would give us the flexibility to choose our own plants and could be planted off site in order to look good from day one – a requirement of the client at this high profile location. I was also attracted to the idea that individual plants or even entire modules could be easily replaced if plants were damaged or died. I water feature was to be created to prevent the people from touching the wall and also to provide seating. I had noticed that the lower sections of the Quai Branly living wall in Paris were being picked apart by the public.

Water feature and  Green Wall - Westfield - Photo Courtesy of Aecom

The Westfield Living Wall is approximately 170m long and 4 metres high and double sided in places. A total of 5000 modules were used and these were planted with 200,000 plants. Modules were planted according to 9 different planting schemes with each panel typically planted with 4 or 5 species.  Several species of fern were used as well as violets and bulbs like snowdrops. The south facing sections were planted with sedums, fescues and other drought tolerant species.

Nigth View of Westfield Green Wall - Photo Courtesy of Aecom

The wall is irrigated with lines that run along the top of each module. About 3 litres of water is supplied for each square metre of wall each time the wall is irrigated. The wall is irrigated about 150 per year. Irrigations is largely automated and sensors in the substrate send a text message to the maintenance company if the walls dries too much because of a fault. Maintenance is occasionally required to cut back, remove or replace dead or straggly plants but after two years (the centre opened in October 2008) still looks good. The water feature has required repairs but the wall is going strong. The living wall has proved popular with the public and it has been suggested that the restaurants which overlook the terrace were easier to let with this feature in view.

Now two years on the Green Roof Consultancy is working with some major companies on a new wave of living walls. We now have the benefit of more competition in terms of the living wall systems and modules that are available and this should drive down prices (high cost has been a factor that has held back rapid uptake of this type of installation). Much has been learnt recently regarding irrigation and water conservation, species selection and the potential to increase biodiversity.  Living and green walls are a great way of greening even the most narrow and difficult places in our cities so expect to see more of them in the future.