National colours of Australia

Their clothes were the traditional white, but the captain Joe Darling arranged for green and gold caps and blazers to be worn for the opening match of the Ashes series.

During subsequent discussions by members of the New South Wales Cricket Association, the colours were reportedly referred to as "gum-tree green" and "wattle-gold".

[4][5][6] The gold colour represents the golden wattle (Acacia pycnantha), which is Australia's national flower.

[8] The golden wattle flower, and the colours green and gold, are also featured on the Coat of arms of Australia.

According to the Australian government, "green and gold have been popularly embraced as Australia’s national sporting colours" since the late 1800s.

Painting of Golden Wattle , by Ellis Rowan , a possible inspiration for the choice of colours.
Australian marathon runners wearing green and gold at the 2006 Commonwealth Games
The Matildas in 2019.
The Kangaroos in 2008.
George Bailey in Australian ODI cricket uniform, 2016.