Australia is one of the few places in the Western world with very heavily regulated and controlled set of awards and wages. You should check the government websites to see the minimum rates etc. Sadly we couldn't find an Aussie version of John Nix Pocketbook.
More specifically, it very much depends on gardener qualifications, and availability in your area. We found in Melbourne 2020/2021:
* Qualified - with a Horticultural Degree and good knowledge of plants and their care, $50/hr.
* General - including use of our equipment, heavy work and chainsaw - $40/hr.
* Casual - no specialist equipment, relatively light duties - $25/hr.
* Lawnmower Man - his own ride-on equipment, taking everything away - fixed quote, worked out to $50-$60 /hr.
* Large Tree - e.g. Eucalypt Regens - quoted by the tree, high $000s + Council fees as required.
