Green Walls

Did anyone follow the floral trail http://www.birmingham.gov.uk/floraltrail around Birmingham this summer? I must admit that amidst my flitting round the city I picked up on several of the displays individually before realising at the end of the summer that they were all part of the trail. Now I wonder how many I missed...

What really drew my attention to the trail was the rather impressive green wall on the borders of the works for the new library in Centenary Square. This is a good example of a modular green wall, in other words it consists of a lot of panels that can be stacked along a wall, with little pockets into which different plants can be arranged, linked to an integrated irrigation system. Even towards the end of September there was a good variety of colours and textures. Anyone familiar with the Rhubarb building in Digbeth will already appreciate the dramatic effect off an artistic display of plants integrated into the building envelope.

These kind of green walls have been used for dramatic impact for several years, particularly in Paris where Patrick Blanc established himself as a world expert in the craft. They are now popping up more frequently in the UK, and can be appreciated for more than their aesthetic qualities. Although there is not a great tradition of research into the benefits of green walls, this is currently changing and the extent to which green walls help clean the air of pollutants and provide shelter and food for wildlife will soon be much better understood.

As a society we have started to realise that people cannot thrive in urban greyness without plants, and technology is helping us find clever ways to bring them back in. But it's always worth remembering at the same time that plants have their own little tricks to get a foothold. As a cheaper and less water-intensive idea, green walls can be naturally encouraged very easily with a simple trellis frame, and there are many attractive climbers which, in a little soil, will do a fabulous job all by themselves without damaging your building.