Moss graffiti by Wallisfurth shows potential of moss as urban cooling

In 2012, street artist Philip Wallisfurth used moss and yoghurt to save a tree in Aachen from a shopping centre: he created the text 'greener living' in two-metre-high moss letters on a construction fence. The enthusiastic public inspired him to continue with 'bio-graffiti', which in 2014 led to a commission from Jack Daniel's in Cologne. Wallisfurth (42) now runs a...