Green facades are self-sufficient vertical gardens that are attached to a structure built along a building’s exterior. The facades differ from other green walls in that the plants are rooted in soil adjacent to the building rather than fastened to the wall itself. The plants receive water and nutrients from ground soil or hanging planter boxes. The concept of the green facade dates back to the Hanging Gardens of Babylon in 600 BC. Green facades have many uses and are considered an ecological technology. Once established, green facades need little maintenance and can grow as tall and as wide as its supporting trellis system will allow, depending on the plant species used.