A Little Bit About Roof And Wall Gardens Now Becoming Very Popular Around The World
by Art Drysdale
by Art Drysdale


Art Drysdale, a life-long resident of Toronto and a horticulturist well known all across Canada, is now a resident of Parksville, British Columbia on Vancouver Island, just north of Nanaimo. He has reno-vated an old home and has a new garden there. His radio gardening vignettes are heard in south-western Ontario over radio station Easy 101 FM out of Tillsonburg at 2 PM weekdays.

Art also has his own website at

November 15, 2015

Above, three shots of the new wall planting at the U.K.’s National Grid parking gar-age, the largest in the U.K. Below, some unusual planters at the Colegrave Ball open house in the U.K. in 2014; and an eight-storey wall garden in Sydney, Australia..



In the United Kingdom National Grid is the latest company to claim the largest living wall in Europe. At their headquarters, known as the National Grid House, just outside of Warwick (in the north of England) at the site that controls the United Kingdom's power distribution, the company recently built a new car park. They then commissioned One World Design to wrap the whole thing with a massive vertical garden measuring 11,054 square meters (119,000 sq. ft.), resulting in a substantial carbon sink that aims to demonstrate the importance of sustainability--even to a power distribution company.

Vertical gardens and living roofs have become enormously popular in recent years. In France, for example, all buildings are required to be topped with either solar panels or a green roof. But vertical gardens are also frequently used to improve a company’s public persona.

National Grid’s commitment to sustainability in all their undertakings has meant that the brief for a new car park on this site would always lead to something extraordinary—with the car park now finished it has literally come alive, according to a recent press release. And alive it is with more than 97,000 plants and 20 different species particularly tailored to attract bees and butter-flies.

The 446-space car park was designed to minimize site disturbance, yet building car parks also creates incentive for employees to keep driving instead of, say, riding bicycles. Since this doesn’t really match up with the green ethos the company is attempting to portray, the green wall helps to offset their environmental impact, at least in the public’s perception.

A lot of thought has gone into this particular vertical garden.

The living wall is designed to add both to the ecology and biodiversity of the area but also it will flower and bloom adding colour and variety with the seasons. Fruit bearing plants are included—strawberries for instance.

It also includes bird and insect boxes, which is an important service in a world where humans are pushing pollinators and other creatures to the brink of extinction. Other sustainability efforts include 558 low-energy LED lights and a porous road to absorb runoff.

Living wall systems are composed of pre-vegetated panels, modules, planted blankets or bags that are affixed to a structural wall or free-standing frame. These modules can be made of plastic, expanded polystyrene, synthetic fabric, clay, and concrete and support a greater diversity and density of plant species (e.g. a lush mixture of groundcovers, ferns, low shrubs, perennial flowers, and edible plants) than green façades. To date many living wall installations can be found in both tropical and temperate locations. Living walls can perform well in full sun, shade and interior applications.

Retaining living walls are engineered living structures that are designed to stabilize a slope, while supporting vegetation contained in their structure. They provide the structural strength to resist the lateral forces exerted by angles greater than the natural angle of repose of soil and protect slopes against erosion. They are often modular for ease of installation and made of geo-textile bags in conjunction with interlocking units, metal, concrete, plastic cellular confinement mats or woven willow plants.

Some systems can perform on slopes up to 88 degrees and many have capacity for variable slope angles as flat as 45 degrees. While performing the same structural function as their more widely known non-living, solid-faced predecessors, all living retaining wall systems and methods must allow for a suitable volume of soil at the face of the system. The growing media must be sheltered from erosion, be accessible to the introduction of plant material either from plugs or seed and provide for long term plant growth. The mature living retaining wall is intended to be fully covered by its internally supported vegetation such that the underlying structural elements are no longer visible as the wall becomes additional green space and habitat for the project.

Living walls systems are designed to permit vertical gardening, planting that adds a unique and aesthetic appeal to anywhere they are placed. In addition, living walls offer many of the benefits of Green Roofs including: improvement to air quality; reduces pollution; reduces heat and cools ambient temperature; reduces the urban heat island effect; reduces noise (can act as a noise barrier); beautifies your property or room.

Thinking about their use in Canadian situations, several cities have invested either in Living Roofs or Living walls. For example, Toronto has a fairly extensive Living Roof at the City Hall, as well as at the newly built Toronto Botanical Garden.

A parkade garage at Vancouver International Airport is reasonably large and colourful. Unfortunately, my photos of it have ‘disappeared’!


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