Came across this last night and thought it would be appropriate here. Every state will be different, but here is the law for GA
"Finally, Georgia House Bill 417, passed during the 1993 legislative session, relates to who can and cannot do landscape design work for money. According to this act, only a Registered Landscape Architect can sell his design. A Registered Landscape Architect is one who passes a stringent Landscape Architect’s Certification Exam administered by the American Society of Landscape Architects and is licensed with the GA Secretary of State’s Office). A landscape contractor, designer or retailers (or anyone who is not a Registered Landscape Architect) who performs design services can not charge for his/her design and must follow up by installing the design. Newcomers to the landscape profession need to be aware of this act if they are considering design services as a part of their business."