Green walls and roofs are couple of ideas that have been around for many years but are only now gaining some popular traction. While they both provide many landscape design benefits, like anything to do with working with nature, nothing is every simple or automatic.
The key benefits of green walls and roofs are perhaps not surprisingly environmental. Urban growth up in recent decades have led to a huge heat sink effect in built up areas. Essentially the dominance of steel, concrete and asphalt have resulted in heat being retained where populations have concentrated. There are numerous negative effects resulting from this effect not the least being reduction in quality of life for those living in these areas. The benefit of green roofs and walls is to combat this effect. In fact I read just the other day about a bus company in Spain that has put a green roof on one of its buses reducing the need to air condition the bus in summer by a dramatic degree. In addition to combating the heat sink effect, green roofs and walls also add to the absorption of carbon dioxide in our atmosphere while adding to the biomass of areas otherwise severely lacking in this department ( think cities )
Visually from a landscape design point of view they provide great opportunities to make the most of giving limited spaces a maximum natural effect. In many new housing lots there are often more square meters available for planting on the surface of the boundary fence than there is on the ground. However I personally struggle with the visual benefit of some approaches to green walls. While I understand Patrick Blanc is considered the modern father of this movement and just saw today another example of his work being celebrated I’m not such a fan of the effect he creates. His style is to bury an entire wall in layers of lush planting ( which the majority love ) but I’d like to see a more nuanced approach. When I get the opportunity to design a green wall in a public place I’ll be using images of cities taken over by jungles from the science fiction books of my younger years as a guide. We’ll just have to wait and see what they look like then.
On a final note, if you are looking to inject a but of green wall or roof action into your landscape design you don’t necessarily need to commit to the instant, tech and resource heavy solutions that commercial projects are employing these days. Some wire or a fame, a vigorous climber and patience will give you the same effect and for potentially much longer than most if not all the current crop of instant solutions.
