Blanc for Green

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Whilst the revitalisation project at the Powerhouse Museum is well underway, another exciting architectural project is also taking shape across the road: Central Park. This urban village, combining residential, commercial and retail spaces, will be completed in 2013 at the former Carlton Brewery site on Broadway.

At its heart, the two residential towers ‘One Central Park’ will be visually connected to the park below through a stunning vertical garden of plants, flowers and vines. Designed by Pritzker prize-winning French architect Jean Nouvel in collaboration with French botanist and artist Patrick Blanc, these towers will achieve a creative symbiosis between nature and architecture.

“The building, together with my Vertical Garden, will be an architectural work floating in the air, with plants growing on the walls ‘ it will create a very special result that will be very new to Sydney.’ says Patrick Blanc about Central Park.

This living work of botanical art will be the world’s tallest Vertical Garden, reaching 150 metres in height, with a colourful assembly of 4,528 native Australian plants from 69 different species. It will breathe and grow, providing wonderful contrasts of colours and textures with the seasons: sprouting in spring, flowering in summer, slowly turning to autumnal colours before shedding leaves in winter.

‘When people see this artwork’ says Blanc, ‘it will look like a natural cliff, as though you have cut a giant slice out of the Blue Mountains and put it in the middle of the city.’

Who is Patrick Blanc’
Patrick Blanc is renowned for turning multi-storied buildings into masterpieces. He is a French botanist and researcher at the CNRS (French national centre for scientific research), where he specializes in tropical plant undergrowth. He invented and patented the concept of Vertical Gardens, or ‘Mur Végétal’ in French. He has created more than 160 Vertical Gardens around the world, including on the Trio Building in Camperdown in 2009, at the Musée du Quai Branly in Paris in 2004 and at MONA in Hobart, Tasmania, in 2010.

After a trip to Thailand and Malaysia at the age of 19, where he saw luscious vegetation naturally growing along cliff sides and ancient monuments, or perennially clinging to waterfalls or rocky slopes, Blanc was determined he could replicate in the city what he had seen in the wild. He conceived the Vertical Garden, aiming at recreating a permanent living plant cover on walls. These would require minimum maintenance as in a natural environment and bring nature back into the midst of the city.

‘Wherever water is available all year long, as in tropical forests or in temperate mountain forests, plants can grow on rocks, tree trunks and soilless slopes. In Malaysia, for instance, out of the 8,000 known species, about 2,500 are growing without any soil. Thus, as seen from nature, it is possible for plants to grow on nearly soilless vertical surfaces as long as there is no permanent water shortage.’

How does it work’
The Vertical Garden is based on good botanical knowledge. Each plant is carefully selected. The location, orientation of the wall as well as the environment, the climate and the micro-climate ‘ taking into account the wind and the solar intensity – are carefully assessed to ensure a sustainable and long-lasting landscape. In November 2009 and in February 2011, Blanc came to Australia and studied the vegetation of the humid temperate forests of the South-East regions and Tasmania.

The Vertical Garden is composed of three parts: a metal frame, PVC panels and a layer of felt. The PVC panels are placed on the wall and are covered with non-biodegradable felt to allow a homogeneous water distribution. Seeds, cuttings or plants are inserted in the felt layer on which they will grow. A pipe is installed at the top of the wall, it’s pierced and programmed by solenoid valves for regular distribution of grey water and of fertilizers low in concentration. It’s a very reliable automated system, with low maintenance needs, and most weeds are unable to grow on the vertical surfaces.

Vertical Gardens provide a sustainable alternative to horizontal gardens. They do not need much space and they make use of unutilised surfaces. Providing they’re watered regularly, these gardens can last for over 30 years with minimal maintenance.

The effect on the environment
Pleasant to the eyes and a shelter for biodiversity, the Vertical Garden is also useful in reducing energy consumption. Patrick Blanc says that: ‘Thanks to its thermic isolation effect, the Vertical Garden is very efficient and aids in lowering energy consumption both in winter, by protecting the building from the cold, and in summer, by providing a natural cooling system’.

It also improves air quality in our cities as it acts a natural air purification system. “On the felt, polluting particles are taken in from the air and are slowly decomposed and mineralised before ending up as plant fertiliser. The Vertical Garden is thus an efficient tool for air and water remediation wherever flat surfaces are already extensively used by human activities’, says Patrick Blanc.

Vertical Gardens recreate a natural environment on man-made surfaces. According to Patrick Blanc, ‘Vertical Gardens are not a criticism to the city and concrete is not pushing nature further away. It brings man closer to nature.’

Dialogue in the city
Patrick Blanc says that his experience over the past twenty years allows him to be confident in the longevity of these gardens, not only because of the plants resilience, but also because this new concept hasn’t been vandalised by people, even in sensitive areas. It is probably thanks to the connection with a natural ecosystem. Patrick Blanc says: ‘Plants become an element of dialogue with man, because they don’t invade the horizontal space, which becomes available for urban activities and the ‘promenade’ of the passers-by’.