The Rural Industries Research and Development Corporation (RIRDC) has announced the backing of a research project that has identified a number of hardy native plants that could be used to grow on walls and roofs of buildings.

 

Dubbed “vertical gardens”, the concept involves setting up slim-line growing beds on the walls and rooftops of buildings where plants grow in specialised soil and are watered using a drip irrigation system.

 

One of the project’s chief researchers, Dr Melinda Perkins from The University of Queensland said that the greatest benefit of a vertical garden is its ability to block heat.


“Apart from being attractive, these gardens can reduce the need for air conditioning in warm weather by shading and buffering buildings from heat,” Dr Perkins said.


“Temperature reductions of up to 17 degrees celsius were achieved inside prefabricated metal buildings that incorporated living walls and rooftops.


“In the built environment this can lead to very significant reductions in energy demand for air conditioners.


“The technology used to grow the plants is widely adopted in Europe, particularly Germany, and is becoming more popular in the USA and Singapore.”

 

The research project identified six native plant species for green roofs and seven for green walls that displayed traits suited to Australia’s harsh sub-tropical environment.


“To be suitable the plants need to have a strong, shallow root system, provide good vegetation cover, be pest and disease hardy, and be tolerant of wind, drought and high temperatures,” Dr Perkins said.


“On the other hand, species prone to become a weed problem or which display aggressive growth rates should be avoided.  Also, where sites are accessible to the public, plants with thorns or which are poisonous to humans are potentially unsuitable.”