Last Updated: Jun 15, 2021
Back in elementary school, most of us probably learned that plants could use the carbon dioxide in the air for photosynthesis to produce oxygen that they subsequently release into the air we breathe. Walking through a dense forest, the sensation of rich, pure air is exceptionally different from the air that many of us breathe in the congested towns and cities where we live. Increasing the “greenness” around our homes, then, is one easy way to improve the air we breathe daily.
While there are dozens of water-friendly landscaping strategies to reduce dependence on agrochemicals, grow healthy and organic food, reduce and prevent erosion, and even improve the thermal performance of your home, most people probably believe that plants and trees belong in the yard and not on the exterior walls of our homes. However, green facades can be a resilient and inexpensive way to create thermally comfortable and visually stunning homes. This article explains how homeowners can sustainably and creatively install a wide range of high-performance and aesthetically pleasing green facades over the exterior walls of their homes.
Green facades are created by purposefully growing climbing plants both up and across the facade of a building. While most green facades are designed from plants that are either planted directly into the soil or in pots at the base of the exterior wall, some green facades place containers at varying levels across the building, especially in multistory buildings.
Green facades are different from living walls. Green facades use a trellis system to hold the vines of plants rooted directly into the ground, a living wall has a system of wall modules such as bags or mini containers that hold the roots of each plant. Living walls almost always require a separate irrigation system, which increases the cost and the complexity of the system. Simultaneously, the plants that make up green facades receive their water requirements directly from the rain outside and soil on the ground.
While both options offer similar benefits and advantages that we explain below, green facades are widely considered less expensive, easier to design and install, and require less maintenance and infrastructure.
First, building a green facade is a relatively easy way to add a creative aesthetic dimension to your home's exterior facade. The climbing plants and ivies used for green facades are compatible with several different exterior cladding options. They can combine interestingly with brick, cement, rock, and other hard exterior home finishes. Besides their visual appeal, however, green facades offer several other benefits and uses, including:
In many cases, the best types of climbing plants for green facades are local and native vegetation that is well suited to the particular climate, soil, and other elements of your region. However, certain types of climbing plants have been adapted to a wide range of contexts and have proven performance in quickly developing a multi-functional green facade. To choose the best type of plant for your green facade, it is important to consider whether you prefer self-climbing plants that don’t require any climbing assistance infrastructure or “twiners,” which aggressively send up stems around a support system.
The advantage of self-climbing plants for a green facade is that you will not have to invest in a separate support system such as cables, ropes, or fasteners. The downside is that some of these types of self-climbers will develop aerial root systems to attach themselves to the wall of your home. If there are any cracks in your house’s exterior, these aerial roots can cause damage over time.
Some of the best-known self-climbing plants for green facades include common ivy, American trumpet, Chinese Wisteria, wild hop, honeysuckle, and hardy kiwi. Some of the best twiners include standard wisteria, Virginia Creeper, and Japanese Spindle. In some cases, you can combine both self-climbing plants and twiners. The thicker vines of the self-climbers will serve as a trellis for the twiners.
Despite the benefits outlined above, green facades are not meant for every home. As we mentioned above, certain self-clinging climbers such as common English Ivy will support themselves with aerial roots that can penetrate cracks and joints in the masonry on the exterior of your home. This can cause structural damage over time, though sound masonry practices will most likely be unaffected. Houses with wood facades would probably do best to avoid green facades, as moisture accumulation could lead to rot and mold issues, both on the exterior and interior of your home.
If you choose a green facade where plant boxes are placed at different levels across your home facade, they will need much more maintenance. Any system that requires extensive irrigation infrastructure also increases the risk of the buildup of moisture inside your home, should the system malfunction.
If you can live with these risks, green facades offer several significant benefits for homeowners in different climates. They are a relatively simple and cost-effective strategy to beautify your home, attract wildlife, improve the thermal performance of your home, and help clean up urban air quality issues.
Tobias runs an agroecology farm and a natural building collective in the mountains of El Salvador. He specializes in earthen construction methods and uses permaculture design methods to integrate structures into the sustainability of the landscape.