Chicago shows Campbelltown the way

An aerial view of the Chicago Botanic Garden green roof. Picture: Chicago Botanic Garden.
An aerial view of the Chicago Botanic Garden green roof. Picture: Chicago Botanic Garden.

The Chicago Botanic Garden has proof that rooftop gardens are much more than a pie in the sky idea.

Campbelltown councillor Ben Moroney recently said he’d like Campbelltown Council to establish its own green roof and champion the concept in Macarthur as a way to soften the influx of high-rise development on its way.

Chicago Botanic Garden’s plant evaluation manager and associate scientist, Richard Hawke, said there were several reasons why Campbelltown Council should follow the garden’s lead including improved stormwater, energy conservation and a reduction in noise and air pollution.

“Additionally, green roofs increase urban biodiversity by providing habitats for insects, birds and animals,” he said.

“Green roofs can also be used to grow food crops.”

The Chicago garden – one of Australian Botanic Garden, Mount Annan boss John Siemon’s favourites – has been split into two parts, with both areas about 740 square metres each.

The south garden features native American plants while the north garden features varieties from around the world.

The Chicago Botanic Garden green roof. Picture: Chicago Botanic Garden.

The Chicago Botanic Garden green roof. Picture: Chicago Botanic Garden.

Mr Hawke said plants were chosen based on their ability to adapt to extreme hot and cold environments.

“One focus of our science program is native plants, so we felt one of the green roofs (the south) should reflect this,” he said.

“The north green roof features plants from anywhere in the world and is especially rich in cultivated plants.

“The message of the north green roof fits nicely with the Chicago Botanic Garden’s mission as a display garden.”

Mr Hawke said when it came to maintenance, more attention was given to the north roof with weeding high on the agenda to ensure plants remained in their “original locations”.

However, the native plants on the south roof were allowed to spread to create a more natural look.

Water usage costs were also kept down as both gardens were “irrigated minimally”.

One of the biggest obstacles with green roofs was ensuring the buildings were able to cope with the weight of the soil, plants, pots and water.

However, Mr Hawke said the Plant Conservation Science Centre was designed specifically to bear the weight of the large gardens.

The Chicago Botanic Garden green roof. Picture: Chicago Botanic Garden.

The Chicago Botanic Garden green roof. Picture: Chicago Botanic Garden.