As the land owner, the City of Adelaide needs to assess and approve your proposal. We do this by way of a simple nature strip...
"To make sure your verge garden meets the City of Marion Council requirements, residents are encouraged to read the attached Verge Garden and Development Guidelines....
Information on website is sparse. Council policy updated in September 2020 is at https://www.campbelltown.sa.gov.au/__data/assets/pdf_file/0022/236524/Road-Verge-Development-and-Maintenance-adopted-1-September-2020.pdf
Verge gardens are encouraged but permits are required. https://www.charlessturt.sa.gov.au/VergeGardens
Prior to any works commencing, complete and submit the Landscaping a Verge Application Form and have it approved. This council also has a No Weed...
Permits required. See the website for guidelines and application form.