National colours of Australia

The national colours of Australia are green and gold. They were established by the Governor-General of Australia, Sir Ninian Stephen, on 19 April 1984; on advice from Prime Minister Bob Hawke.

The gold colour represents the golden wattle (Acacia pycnantha), which is Australia's national flower. The uniforms of Australia's national sports teams are usually green and gold. The golden wattle flower, and the colours green and gold, are also featured on the Coat of arms of Australia.

The Australian government states that, to be used correctly, the colours are placed side-by-side, with no other colour between them. The exact green and gold colours are specified as Pantone Matching System numbers 348C and 116C. The colours are always referred to as "green and gold", respectively.

Before 1984 three colour combinations unofficially represented Australia:

According to the Australian government, "green and gold have been popularly embraced as Australia’s national sporting colours" since the late 1800s. Nearly every current Australian national sports team wears them (although the hues and proportions of the colours may vary between teams and across eras). Australia's cricket team first wore the colours in 1899, in the form of the baggy green, the cap presented to Australian cricket players.

The first Australian national sporting team to wear green and gold was the Australian cricket team that toured England in 1899. 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. Previously, the team had had no uniform cap or blazer colours but wore an assortment of club or state colours. The Australian cricket team continued to use the colours thereafter, and in 1908 the colours were ratified as the official team colours for future Australian cricket teams. 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".

...
Wikipedia