Why do you want a green wall?
Aesthetics or feature wall
A popular reason to install a green wall is to make a visual statement or impact on onlookers. Though all green walls have some aesthetic appeal, a feature wall will be designed with visual appearance paramount.
Typically costs are not a driving factor and plants are selected for their appearance and diversity in colour, shape or even scent.
Walls designed to bring biodiversity into the local environment will need to support a variety of plant species. Research from green roof installations suggests that the mix of plants is more important than their origin, i.e. native plants are not essential.
In some cases it may be important to select a type of plant that specifically attracts a particular bird or insect species to meet design objectives.
Where thermal insulation or noise reduction is required and the wall has been selected as cladding, the physical construction of the green wall system needs to be adequate to provide the necessary building protection in addition to providing support for vegetation.
In these situations there is a need to evaluate the impact of green wall loadings on the strength of the building. When thermal properties are being considered the thickness of substrate and type of plants used may also influence design choices.
Air purification / dust suppression
If improvements in air quality are a desired benefit from a green wall, plant species should be selected for their ability to capture dust or toxins.
Longevity and robustness of the plants are also likely to be important if the location of the wall is in a particular harsh environment, for example next to a busy road or a construction site.
Often a cost-effective green wall is important in these situations, especially when aesthetic impact is not the main objective.
With the correct selection of plants indoor walls can be particularly useful at cleaning air inside buildings.
Access is a major factor for a green wall intended for growing produce. The need to tend and harvest plants may restrict the height or size of the wall. A vertical allotment needs to allow easy, cost-effective access for the growers on a regular basis.