What makes the city different from the country? No, it’s not roads, or malls, or the variety of grocery stores. Think hard: what does the country have that cities often don’t? Greenness.

In suburban and rural areas, green is everywhere. There are grass, bushes, trees, and flowers. People have big yards and sometimes, there’s even a bit of forest. Not only is the color green known to have healing properties, but it’s been shown that exposing a patient to garden-like areas can speed recovery from surgery, infection, and other ailments.

Cities are notoriously grey and devoid of wide open green space. That’s because space is at a premium. High concentrations of humans mean that green areas are often torn up or paved over to make room for new places to put ourselves. We build office buildings and high-rise apartments without thinking about how it could impact our health. Now, a new trend in design is infusing green back into our urban environments, without wasting any space.

Vertical gardens are nothing new. As Ecomagination reports, the first one was installed at the Museum of Science and Industry in Paris in 1988. Still, few vertical gardens can rival the complex combination of gardening and architecture championed by Canadian firm Green Over Grey.

More than just normal planters stacked in a vertical formation, GOG’s living walls consist of a frame, waterproof panels, an automatic irrigation system, special materials, lights when needed and of course plants.

Here’s how it works: The frame is built in front of a pre-existing wall and attached at various points; there is no damage done to the building. Waterproof panels are mounted to the frame; these are rigid and provide structural support. There is a layer of air between the building and the panels which enables the building to ‘breath’. This adds beneficial insulating properties and acts like rain-screening to protect the building envelope.

Without the need for soil, the designers have significantly more control over the way plants are arranged allowing the green walls to become living art. Succesful installations have been built both indoors and out. There is no limit to the dimensions they can plant, as even with mature plants their green walls weigh just four to five pounds per square foot, according to Patrick Poiraud, GOG’s design consultant and principal.

* Beth Buczynski, EarthTechling