DO NOT SEND

South Australia has strict rules for transporting plants/soil into their state.  I know, because every time I go there I see the road signs regarding plant materials (I'm live an hour from SA).

I would send the following link to the South Australian buyer and tell them that you are not comfortable sending plant materials into SA

http://www.pir.sa.gov.au/biosecuritysa/planthealth/importers

Here is just one little bit from that site:

"There are strict regulations and requirements regarding the entry of fruit, vegetables, plants and plant related products into South Australia. These are not permitted to enter unless accompanied by Plant Health certificatication declaring that the produce is free of disease or has been appropriately treated."

If YOU send plant material into SA you may find yourself with a "please explain" from the relevent SA authority.