[Reading Science] The Heyday of Urban Mural 'Vertical Gardens'

The vertical garden of the Seoul Metropolitan Government Building, registered in the Guinness World Records as the world's largest vertical garden.
[Photo by Seoul Metropolitan Government]

[Asia Economy Reporter Kim Jonghwa] Why are people flocking to the park near the company, filled with trees and flowers, during a short lunch break? Could it be because they see the park as a healing space, a place to rest even briefly amidst busy and intense lives?

Green spaces in the city are a refuge for everyone. Recently, buildings that are not parks but give off a pleasant and comfortable feeling have caught the eye. Large buildings covered with plants create a sense of familiarity rather than the unfamiliarity of the city for those who look at them.

Beyond creating parks in the city and green gardens on building rooftops, buildings are now being constructed where plants can densely grow on the exterior walls. Gardens designed so that plants can grow or be installed on vertical walls are called "Vertical Forests," or "Green Walls," or "Living Walls."

A metal frame is fixed to the wall, then nonwoven fabric is laid to allow plant roots to take hold, and waterproofing is done using materials like polyvinyl chloride (PVC). Water is supplied through a pump system to create an environment where plants can grow. Nowadays, vertical gardens are sometimes created by planting plants directly into concrete so that they can grow.

Most famous buildings recently reportedly create vertical gardens. What are the actual advantages of creating vertical gardens? Plants absorb water through their roots and evaporate water through their leaves, taking away surrounding heat in the process. This can lower the temperature around the building by up to 10°C.

These days, plants are even being planted directly into concrete.
[Photo by YouTube screenshot]

In a situation where securing green spaces in the city is not easy, vertical gardens have emerged as an excellent alternative. Plants absorb indoor pollutants such as sulfur dioxide and ammonia as well as fine dust. A research team in the UK even published results from actual experiments showing that installing vertical gardens is more effective than planting trees.

Vertical gardens also save energy. In summer, the surface temperature of buildings rises tremendously, causing indoor cooling systems to work harder. However, with vertical gardens on the exterior walls, plants reflect solar heat and can lower indoor temperatures by about 3 to 5°C during summer. Conversely, in winter, they prevent indoor heat from escaping outside, saving heating costs.

When the temperature difference between the inside and outside of a building is large, building materials expand and contract, causing cracks or corrosion. Vertical gardens reduce this temperature difference and block direct exposure to acid rain and ultraviolet rays, making buildings stronger and longer-lasting. They also help birds adapt to urban environments and serve as habitats for insects, greatly aiding urban ecosystem restoration.

The most representative vertical garden is inside the Seoul Metropolitan Government building. Completed in 2012, the vertical garden in the Seoul Metropolitan Government building expresses the feeling of the grass from Seoul Plaza climbing the wall in wave patterns. Covering 1,516㎡ of wall space at a height of seven floors, this vertical garden fills the entire front indoor space with 63,000 plants of 14 species including Sanhosu, Aglaonema, Scindapsus, and Spathiphyllum.

A vertical garden created on the outskirts of Busan Museum of Modern Art.
[Photo by YouTube screenshot]

It is registered in the Guinness World Records as the largest in scale worldwide and absorbs fine dust while controlling indoor temperature and humidity, reducing the temperature difference between summer and winter to save energy. Notably, this vertical garden is an eco-friendly garden using energy generated from solar power and geothermal energy installed on the rooftop, as well as rainwater.

The vertical garden at the Busan Museum of Modern Art is also well known. It was created by the world-renowned botanist Patrick Blanc, who planted 175 species of native Korean plants. Patrick Blanc broke the fixed notion that gardens are on the ground and created vertical gardens on vertical concrete walls without soil using air plants.

Vertical gardens are part of small efforts to turn cities into forests. Everyone can feel the refreshing sensation when discovering a green wall among gray concrete. Patrick Blanc described vertical gardens as "paintings encountered by chance in the city." In an era where life in large cities with habitual air pollution is inevitable, wouldn't it be great if more vertical gardens appeared?