It’s Time Colleges Looked at Living Walls

A green wall at the U. of Guelph (U. of Guelph photo)

A recent study at the University of Michigan, designed to examine the ways our brains respond to our surroundings, found that we are profoundly influenced by the amount of greenery we see on a daily basis. Researchers measured the cognitive deficits caused by a short urban walk, showing that students who walked around an arboretum performed significantly better on working memory and attention tests than those who had taken a walk downtown. (Imagine if the students had wandered Manhattan rather than the relatively sedate Ann Arbor.) The authors of the study believe this is due to demands that the noise and bustle of city streets place our limited cognitive capacity: Basically, the stress of an urban commute leaves us mentally scattered and irritable well before we arrive at work, and we don’t really recover. Green, natural settings help to restore our focus and replenish our cognitive capacity.

The study is one of dozens, if not hundreds, documenting the positive cognitive and psychological effects of green space on our minds. Other research has demonstrated that kids with attention-deficit disorder are better able to focus when placed in a natural setting, that domestic violence occurs less frequently when homes have a view of trees or fields, and that hospital patients recover more quickly when provided glimpses of nature.

Unfortunately, the urban environments in which people could benefit most from greenery are the environments in which finding space for it is most difficult. So designers are finding creative new ways to incorporate plants into existing infrastructure. Green roofs are one example, and are growing in popularity—not only because they provide a mental break from the city, but also for their usefulness in purifying the air, reducing the urban heat-island effect, and helping to cool buildings in summer heat.

The green wall at the U. of Guelph is four stories tall. (U. of Guelph photo)

The next frontier is a little less common: green walls. Typically, a frame with small pockets of soil or another growing medium is installed over the top of a waterproof membrane, which shields wall and insulation behind it. Irrigation channels are added, and the plants are often arranged to form some kind of design. The most famous and beautiful of these walls lives at the Musée du Quai Branly in Paris.

Also called vertical gardens, biowalls, biofiltration systems, or even wall jungles, these living walls are not a new idea. A kitchen window box for herbs is a miniature version, but a true living wall can extend for stories, eliminating the need for brick or siding.

Exterior living walls share some benefits with green roofs, such as capturing and filtering stormwater runoff before it overloads urban sewer systems, cooling interior temperatures on hot days, saving energy, and helping to protect the walls themselves from sun and weather damage. They also provide a habitat for urban wildlife, and may even help to muffle street noise.

Drexel U. plans to include a green wall in a new, six-story science building designed by the Canadian firm Diamond & Schmitt Architects. (Drexel U. image)

When installed inside a building, bio-walls serve the same wall-protecting function, and may even improve the residents’ health, since some plants have proven abilities to filter toxins and chemicals from indoor air. Depending on the conditions, they could also contribute to a tasty lunchtime salad, since herbs, greens, tomatoes, and other vegetables can be grown successfully in vertical gardens. Several architects and designers have even imagined “skyscrapers of the future,” clad in living walls that could feed thousands.

So why are there not more living walls in the university system? They’re good for the buildings, good for the residents, and even good for students, who could help with design and maintenance as part of their coursework. Canada seems to be making strides, with at least three significant installations at universities. The University of Waterloo has three walls, the University of Guelph has an impressive four-story wall, and Fleming College at Frost has a hydroponic model that includes a mini-waterfall.

Tyler Fallwell, a facilities-staff member at the U. of Lethbridge, tends the green wall in the Alberta Water and Environmental Science Building. (U. of Lethbridge photo)

However, I have yet to see a large-scale installation at an American college. Drexel University, in Philadelphia, has plans to start installing a bio-wall in the fall which will cover four stories with native plants, but otherwise, the projects that do exist seem to be small-scale, student projects only. Why the delay? Given the long-term benefits of living walls, it seems they deserve another look. —Xarissa Holdaway

Xarissa Holdaway, a frequent Buildings & Grounds guest blogger, is campus e-news coordinator for the National Wildlife Federation’s campus-ecology project. You can read her previous posts here.