About Green Walls
The term "green walls" encompasses all forms of vegetated wall surfaces. However, there are three major system categories that fall under this term's rubric: green façades, living walls, and retaining living walls.
Green façades are systems in which vines and climbing plants or cascading groundcovers grow into supporting structures that are purposely designed for their location. Plants growing on green façades are generally rooted in soil beds at the base of the structure, in elevated planters at intermediate levels, or on rooftops. Depending on climate, choice of species, depth of soil bed, orientation, nutrition and irrigation regime, green façades may take several seasons before achieving maturity. Green façades can be attached to existing walls or built as freestanding structures. They are used to shade glazed façades, to provide degrees of privacy and security, to screen or embellish parking structures, patios and walkways, and are built as arbors, trellis structures, baffles, or fences.
Living Walls (A.K.A. biowalls, 'mur' vegetal, vertical gardens, or modular green walls)
Living wall systems are composed of pre-vegetated panels, modules, planted blankets or bags that are affixed to a structural wall or free-standing frame. These modules can be made of plastic, expanded polystyrene, synthetic fabric, clay, and concrete and support a greater diversity and density of plant species (e.g. a lush mixture of groundcovers, ferns, low shrubs, perennial flowers, and edible plants) than green façades. To date many living wall installations can be found in both tropical and temperate locations. Living walls can perform well in full sun, shade and interior applications.
Retaining Living Walls
Retaining living walls are engineered living structures that are designed to stabilize a slope, while supporting vegetation contained in their structure. They provide the structural strength to resist the lateral forces exerted by angles greater than the natural angle of repose of soil and protects slopes against erosion. They are often modular for ease of installation and made of geo-textile bags in conjunction with interlocking units, metal, concrete, plastic cellular confinement mats or woven willow plants. Some systems can perform on slopes up to 88 degrees and many have capacity for variable slope angles as flat as 45 degrees. While performing the same structural function as their more widely known non-living, solid-faced predecessors, all living retaining wall systems and methods must allow for a suitable volume of soil at the face of the system. The growing media must be sheltered from erosion, be accessible to the introduction of plant material either from plugs or seed and provide for long term plant growth. The mature living retaining wall is intended to be fully covered by its internally supported vegetation such that the underlying structural elements are no longer visible as the wall becomes additional green space and habitat for the project.
Green Walls 101: Systems Overview and Design is a half-day course presented by Green Roofs for Healthy Cities. Click here to see upcoming dates and locations.
Green Roofs for Healthy Cities has a number of Corporate Members that manufacture a variety of green wall systems, including: