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Skyscrapers Dripping in Gardens Look Great — Until the Mosquitoes Swarm

Bloodsuckers overran a tower in China. Does this mean the whole idea is bad? We asked an expert to weigh in.

A series of concrete skyscrapers with lush balcony gardens covered in tropical plants
Qiyi City Forest Garden in Chengdu, China, was billed as an “eco paradise,” but a mosquito infestation has kept residents from moving in.
Barcroft Media via Getty Images

Most apartment towers feel far removed from the natural world. For this reason, seeing a skyscraper that’s alive with plants and trees seems both futuristic and surreally inviting. Wouldn’t it be amazing to have your own Eden in the air? It’s a fantasy that’s fueled such projects as Stefano Boeri’s Bosco Verticale and Nanjing Green Towers, Koichi Takada’s Urban Forest, and dozens of other verdant architectural concepts. This week, Thomas Heatherwick, the man behind the Vessel, unveiled a design for one in Singapore that’s literally named Eden. It seems like an urban paradise, but this cautionary tale from Chengdu — the capital of the Western Chinese province of Sichuan — may temper our excitement.

Chengdu has made it a mission to become a garden city of sorts. The Qiyi City Forest Garden — an eight-tower housing development — was billed as an “eco paradise.” Each of the 826 units (which have all sold) has its own plant-filled balcony that looks like an overgrown back yard in the sky. But here’s the catch: mosquitoes, and lots of them. They love the gardens — and they also love sucking the blood of people who live in them. The infestation is so bad that fewer than a dozen families have moved in.

So, is this a good idea gone wrong? Or was it just poorly thought out to begin with? To answer some of our questions, we talked to Daryl Beyers, a landscape architect with over 20 years of experience, an instructor at the New York Botanical Garden, and the author of The New Gardener’s Handboook. Beyers has also designed a number of rooftop and terrace gardens across NYC, and, according to him, the short of it is: It’s not an inherently terrible idea, but it has to be done right.

“Just because it looks cool, absorbs CO2, is a noise buffer, and offers psychological benefits, doesn’t mean you don’t have to do it properly,” Beyers says. “And I think [the developers] rushed into it. They didn’t think about the maintenance.”

The problem in Chengdu is partly a result of bad design, but mostly a clear case of neglect. “You can’t have a garden without a gardener,” Beyers says. “They [developers] were touting it as a manicured garden outside on your deck. If it’s manicured, someone has to do the manicuring.”

Mosquitoes love water, and Chengdu’s humid climate and months-long monsoon seasons offer plenty of it. Beyers, who looked at images and video of the Qiyi City Forest Garden, believes that the plants are growing in containers on the balconies, which are collecting water. The balconies themselves likely don’t have proper drainage, which means the water is pooling and standing stagnant. Meanwhile, the plants themselves, which were chosen for their noise-reducing and pollution-absorbing traits, are overgrown — providing lots of shade for the mosquitoes to thrive in.

A better way to do it, according to Beyers, would be to pick dwarf plants that won’t grow and become overgrown so quickly. Better yet: allow the residents to pick the plants they want to grow. One site advertising Qiyi City mentioned that the developers will send gardeners four times a year to tend to the gardens, but even that’s not enough; Beyers says once a week is more realistic.

Compared to Qiyi City, Bosco Verticale in Milan has been a success story, both as the poster child for vertical forests and for the people who live there. A recent report from the World Green Building Council found that residents really love it there. In that case, the architects worked closely with an architectural botanist named Laura Gatti to make sure the plant palette — over 500 medium-size and large trees, 300 small trees, 5,000 shrubs, and 11,000 plants — would grow well and look good.

If the architect, landscape designer, and horticulturists listen to one another (and the gardens are actively tended to), the plantings can be successful. Beyers suspects that didn’t happen in Chengdu.

“It is sort of apocalyptic, and that’s what nature will do to all our cities if everything goes to hell,” he says. “You see it in the movies. Plants will do those things.”