The Sustainable Landscapes Research Group, Department of Architecture and Landscape is pleased to announce the forthcoming ‘Living Walls Knowledge Transfer Day.’ This mini conference will host guest speakers as well as staff from the University discussing various aspects of living walls, including the state of knowledge as well as talks by all the key manufacturers and installers of living walls as well as nurserymen. The manufacturers will also display their products, so this will be a great opportunity to inspect the systems close up. For more information and ticketing please see:
https://www.eventbrite.co.uk/e/living-walls-knowledge-transfer-day-tickets-6189893137
Please do not hesitate to contact Shelley Mosco (s.mosco@gre.ac.uk) should you have any questions regarding this event.
I was recently walking up the Edgware Road and came upon the Green Wall and a week or two later it was featured in Landscape Design.
I loved coming upon it as a complete surprise. In front of you is something that defies logic…. a garden at right angles to the world, a vertical parterre. As a wacky bit of indulgent design, it works!
I was surprised to see that the objective of the wall was to act as an air filter for London’s pollution, capturing particulates and giving back oxygen. Surely if you want do this by plants a more efficient, cheaper and more sustainable way is to plant trees or climbers?
Interestingly the total price of the Green Wall was not mentioned in the article. I suspect it is somewhere between £100,000 and £200,000 when you have considered all the negotiations, site acquisition, engineering, new technologies, irrigation systems, design, maintenance, publicity and interpretation. The most unsustainable feature of the Green wall is its on-going maintenance. It requires constant watering and very high level cutting back which can only be done with a very tall “Cherry picker”. In addition, the plant containers will not doubt degrade in 10 to 20 years, resulting in the wall having to be completely rebuilt. During that 20 years the leaf area of those plant will have stayed constant during that period due to the clipping. In other words the air cleaning affect will not have increased.
If you consider trees as “air cleaners”, they cost approximately £100 for an urban situation, much more in difficult sites. So you might get 1000 trees for £100,000. Each tree requires early maintenance for three years, and after that minimal care assuming they were planted in the right place. Each year, the leaf area enjoys compound growth additionally providing shade. I suspect a mature London plane would provide more leaf area than the Green wall. Thus, 1000 trees would provide a thousand times the air cleaning power.
The other benefits of green walls is they keep building walls cool in Summer. However there is a tradition of providing green walls on buildings by growing climbers, for example Virginia creeper, ivy or Wisteria. Again, this is a more sustainable and cost effective way of exploiting vertical wall space. If done well, it requires a large plant pit and substantial wall supports. After that, the creepers need to clipped back from the windows or the roof tiles. This does not offer the same variety as the Green Wall in Edgware Road, but designers could experiment with a variety of creepers. It does however offer air cleaning at a fraction of the Green Wall in terms of capital and revenue.
Given the obvious benefits of trees and climbers in filtering our air in a sustainable and cheaper way over the short and long term, why did the Greater London Authority, plant such an ostentatious piece of garden design. I suspect because there was not a budget for ostentatious art, but there was one for pollution reduction. If so well done! But if we really are serious about using plants as sweeteners of our polluted city air we should be planting Urban Forests with creepers hanging off all our buildings; an Urban Jungle, which given Climate Change temperature rise, would be cool in so many ways!
John Meehan, Environment Manager, Essex County Council