July 31, 2009 by Robin Plaskoff Horton
When I shot these photos of Patrick Blanc’s green walls, or vertical gardens, of the Musée du Quai Branly in Paris, I didn’t realize then that, in addition to their beauty, green walls offered significant ecological benefits similar to, but not the same as, green roofs.
My friend Susi at the great wall of Patrick Blanc
According to Low Impact Living, because green walls are vertical, you can’t capture and filter as much storm water through them as you can with a green roof (although with certain configurations you can route water from the roof through a wall system). Also, you don’t get quite as much insulation bang for your buck since in most buildings more energy is lost or gained per square foot through the roof than through the walls. However, a well-designed green wall on the south side of a building will reduce cooling demands and increase comfort in the summer.
The British firm, BioTecture, contends that storm water attenuation panels can absorb rainwater and that green walls, when used indoors, purify the air since plants are efficient pollution filters.
There are some significant benefits over green roofs. Fruits and vegetables can be grown on green walls, and you don’t have to have access to the roof to care for or harvest them.
Looking through the window to the interior garden
Also, think about the benefits in our cities if green walls were more widespread. Green spaces wouldn’t be limited to just rooftops, parks or streetside planting areas, but could instead hide or replace some of the concrete and glass on our buildings. Streets would be cooler. Vegetables could be grown in urban spaces that currently sit unused, allowing city dwellers to eat more locally grown food, and reducing the impact of shipping in food from far away. At least in a small way, cities could begin to reduce some of the carbon they generate.
So, the next time you’re thinking about replacing a wall at home or redoing an internal or external wall where you work, think about throwing some green into the mix.