the Green Wall, Botanical Brick invented by Professor Stanley Hart White at the University of Illinois Urbana-Champaign in 1938).

Patrick Blanc's contemporary patents are responsible for modernizing and popularizing the garden type.

A network of pipes controlled by valves provides a nutrient solution containing dissolved minerals needed for plant growth.

The roots of the plants take up the nutrients they need, and excess water is collected at the bottom of the wall by a gutter, before being re-injected into the network of pipes: the system works in a closed circuit.

Plants are chosen for their ability to grow on this type of environment and depending on available light.This system exemplifies Blanc's ideas as a scientist and also the 15th target of the Haute Qualité Environnementale ("High Quality Environment") project, although the latter gives particular stress to use of more local species, at least outdoors.