Throughout the world architects are designing green buildings, whether it’s in their sustainable construction, environmentally friendly operation or actually green by style.

It’s broadly titled biophilia, connecting people with nature, and it can lead to some creative and innovative designs.

But now we are finding that literally greening the world — by covering building walls and roofs with vegetation — can also come with some unexpected problems.

In the Chinese city of Chengdu, a vast green experimental housing estate of 826 apartments was constructed where people can live in a vertical forest with every open space and balcony containing live vegetation.

Trouble is they must share the plants with a scourge of mosquitoes and other bugs. Most apartments in the Qiyi City Forest Gardens development were sold by April 2020, but six months later only a handful of families had reportedly moved in.

The towers were built in 2018 and plants were provided to reduce noise and clean up pollution. But the plants thrived, while sales moved slowly, and no one was clipping the greenery to keep it in control.

Now mostly empty balconies have cascading branches of plants overtaking space, blocking windows.

It might not help that Chengdu and its population of 16.3 million people are located in Sichuan, central China, which is humid and semi-tropical, a perfect environment for fast-breeding mossies.

But a slow uptake, with tenants slow to move in, made the problem worse as the plants subsumed their buildings.

Keep reading on TheConversation.com