Central Park Green Wall

Sacha Coles, a director at landscape architecture firm ASPECT Studios, has been involved in some of the most well-known public spaces in our city, such as Darling Quarter and Angel Place. We found out why green roofs and walls inspire him.

Green roofs and walls introduce plants to the surface of existing structures. Green roofs can cover at least 30 per cent of roof space with greenery. Green walls can be freestanding, or part of a building that is covered with vegetation.

Sacha says that green roofs and green walls have immense potential to create positive effects on our urban landscapes.

‘They can also provide opportunities for growing food to localise food production and create opportunities to socialise,’ he says.

Because of this, green walls and roofs are cropping up in urban areas around the globe to increase the quality of urban life. Green roofs and walls can offer improved air quality, a habitat for biodiversity, create more livable spaces and even help cool the city.

Sydney in particular will benefit from having more of these lush spaces. In 2012 the City developed the Green Roofs and Green Walls Strategy, and we’re also developing a policy to make building a green roof or wall even easier.

Sasha notes that increasing the number of green roofs and walls in the city can improve our food production.

‘As our productive food belt is increasingly threatened by housing developments on the fringes of Sydney, green roofs give us the opportunity to support and localise the growing of our everyday food needs.

‘As Sydney increasingly moves towards having higher density living in our city there will be pressure on existing public open-spaces to cater for higher use through higher population.

‘Green roofs take advantage of whole new strata of untapped green space that is able to compliment the important role of our existing public parks and open spaces.’

There are green roofs and walls springing up everywhere in the city. However there are almost limitless opportunities for more.

‘The most important criteria is that green walls are created in places which have a large impact and can be easily maintained,’ says Sacha. ‘I think Sydney could benefit from a large scale green roof above the rail lines south of Central railway station which would create a pedestrian and cycle connection between Surry hills/ Prince Alfred Park and Chippendale/Broadway.

‘I’d (also) love to see the Royal Botanic Gardens connected to The Domain across the Cahill Expressway, green walls at the entries to the Cross City Tunnel and an improvement of the green space on the domain car park roof.’

You can get involved too. Green roofs and walls are not only found in the public domain, but the idea can be scaled down to suit your home. Pallet gardens are gaining in popularity, but there are tonnes of different possibilities.

‘There are a range of options with green walls depending on how much time and money one wants to invest – from the do-it-yourself system to proprietary high-quality and high-cost systems’, Sacha explains.

‘The simplest and lowest-cost systems would be using cascading plant species in hanging baskets fixed to a brick or timber wall. Or try growing plants up a wall, assisted with some stylised mesh backing. This option would be hand watered and in time will create a ‘green facade’ at low-cost. Another option for low-light areas is to mount epiphytes – plants growing in trees such staghorns, Elkhorns and rock orchids – onto a board and then secure onto your wall.

Another option is a felt-pocket planter that is mounted to the wall and includes cascading species of plants. Soil sits within the felt pockets and has drip irrigation.  This could be hand watered for a more cost-effective approach.

At the more costly end of the spectrum there are modular systems which need irrigation and drainage connections. Often the plants are pre-grown and installed as a spectacular living wall, complete from day one.’


Sacha is part of a free green roofs and walls forum on 3 August at the Powerhouse Museum, where he is talking about the value of urban design and how it can connect us to both each other and the world.

The forum is brought to you by the City of Sydney and the University of Technology Sydney and is part of Powerhouse Museum’s Sydney Design 2013. Click here to attend the forum.

** Hero image features a green wall on the Central Park building, a joint venture between ASPECT studios and OCULUS.

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