A living wall (also commonly known as a green wall, eco wall or vertical garden) is a panel of plants grown vertically up a wall. They are an effective way to introduce a large number of plants in a relatively small space. Because living walls don’t take up floor space, they work particularly well in situations where space is at a premium – e.g. in city centres.
Although living walls are usually grown on the external walls of buildings, they can also be installed on internal walls to provide a living art form as well as multiple environmental and health benefits.
An internal living wall
Living walls are an effective way of introducing the natural and multiple benefits of plants, particularly to urban environments. They contribute towards sustainability and their benefits include:
Human beings have a need to connect with nature – a phenomenon commonly called ‘Biophilia’. Being around nature helps people feel happier, be healthier and also more productive. In our increasingly urban environments, living walls help rebalance city landscapes and restore a natural element.
Plants not only produce oxygen, they also remove harmful pollutants from the air. In recent years, we’ve become more aware of the number of chemicals present in our homes and workspaces. These chemicals can contribute to the phenomenon known as ‘sick building syndrome’. Houseplants are a good way to help purify the air. Living walls achieve a similar outcome but on a much bigger scale. External living walls have a big impact on improving air quality between buildings in cities. These spaces are hotspots for the accumulation of harmful gases and particles, and living walls have been proven to reduce these by up to 60 percent.
Cities often suffer heat spots due to the urban heat island effect (where the heat in cities gets trapped, making them much warmer than their surrounding rural areas). This exacerbates pollution within cities and creates an unpleasant environment. Living walls help reduce these urban hot spots by the process of evapotranspiration – where the air temperature is lowered through a combination of water evaporation and plant transpiration. The greater the level of vegetation, the greater the temperature reduction.
Living walls help cut energy costs by providing insulation for buildings. The layer of vegetation helps keep buildings cool in summer and warm in winter. Plants also provide shade that reduces the amount of heat absorbed by the building from the sun and the plants and growth media help keep the cold out in winter. These reduced extremities in temperature mean a reduced need for air conditioning and heating, which results in reduced running costs.
Living walls act as an insulator against sound, which is particularly helpful in urban environments.
Living walls not only provide a rich diversity of plants in urban spaces, they also provide a home for insects and birds, helping promote biodiversity in cities and towns.
An external living wall
You can generally create a living wall in one of three ways:
Panel systems – where panels with pre-grown plants are fitted to a wall either indoors or outside.
Tray systems – a more versatile solution, often used indoors and best suited for living artwork. The plants are pre-grown and inserted into the wall on site.
Freestanding walls – most commonly used indoors and easy to move around. The plants in freestanding walls can be changed relatively easily.
Most living walls are fitted with irrigation systems although some require manual watering. Hydroponic systems are common and keep the plants watered by drip-irrigation. Recirculation systems require the least maintenance as water is pumped round the system multiple times, until it runs out, at which point a water tank is refilled.
There are many plants suitable for living walls. When choosing which plants to use, consider their air purifying abilities, the growing conditions and the look you are hoping to achieve. Your choice of plants should reflect the location and purpose of your wall.
Living walls do require a fair amount of maintenance. Professional installation companies will usually maintain a living wall for the first year as part of the set up cost, then agree a maintenance programme with the client going forwards.
Sources:
https://www.biotecture.uk.com/
https://www.ambius.com/green-walls/ultimate-guide-to-living-green-walls/
https://www.rhs.org.uk/advice/profile?pid=547
