Developing Green Roofs In Hong Kong

Landscape architects are understandably misunderstood in Hong Kong. Just look around: we’re surrounded by concrete. Our green countryside parks are being consistently threatened by development. And most people live in tiny flats surrounded by more concrete where they are lucky to get anything to grow besides mould.

Yet that is why landscape architects are vital to our community. Their job is to make sure that we live in harmony with our environment, from a micro to macro scale. That includes looking at how climate change is affecting the environment, improving slope drainage to prevent landslides during heavy rains or examining how plants can improve soil conditions in contaminated industrial areas. On the more familiar side, landscape architects also design parks and gardens.

“Landscape architecture is difficult to define because it is a very broad discipline,” explains Matthew Pryor. The Edinburgh-trained landscape architect is The University of Hong Kong’s Landscape Architecture head of division and assistant professor, and has taught at HKU for more than a decade.

Pryor was introduced to landscape architecture via golf. “I was a keen golfer when I was a kid,” he says. “But I knew I wasn’t good enough to be a pro. So I thought that I could design golf courses. One of my teachers suggested pursuing landscape architecture as a career … And, after practicing for many years, I have to admit that not once have I ever designed a golf course!”

“Hong Kong is a great laboratory,” he exclaims enthusiastically. “There is a growing concern in the community about how public spaces are shaped and used, so that pedestrians can enjoy them. Another area is community farming. We are currently compiling a manual to explain to homeowners and developers how to best utilise Hong Kong’s many flat roofs for vegetable and ornamental gardens.”

Green roofs have been proven to be successful for reducing the need for heating and air-conditioning as they act as natural insulators. It may come as a surprise to many that Hong Kong has a 40-year-history when it comes to developing green roofs. Looking at a Google map, though, and it becomes apparent that a lot more can be done. Pryor believes that the problem is mostly due to lack of ownership. “For a green roof to work, it must have a function,” he explains. “It can be a family space. It may be where children can play. Or a workshop. Or where vegetables are grown. But there must be a reason for people to be up there. Then they will have incentive to tend to it.”

Pryor developed an experimental vegetable garden on the roof of HKU’s Runme Shaw Building with students earlier this year to provide fodder for the manual he is compiling. By re-using existing containers such as oil drums, plastic crates and wooden skids, students are learning what best works for different types of vegetation while up cycling materials. Beans and other climbing vegetables are outfitted with bamboo fences or metal arches to encourage growth. Discarded CDs are suspended to naturally ward off pests, as the slightest breeze cause them to move and sparkle.

“The planters we use are heavy enough so they don’t blow away during a typhoon, but are still small enough to be movable — that was one of the critical aspects of our garden’s design,” says Pryor. Students from any department in the university can participate in the farm, but they must attend to their own crops. The manual, which includes how to manage soil drainage on a roof and which crops are most suitable for Hong Kong’s subtropical climate, will be available on HKU’s website.

There is currently a lot of interest from other schools who want to encourage their students to foster green thumbs. “It is important for schools with green roof programmes to keep kids hydrated while they are tending to their plants,” notes Pryor. “Young children can play in the sun for hours and not realise they are getting heat stroke. Hong Kong roofs can get very hot.”