Speaking from my experience in Poland for example, in order to open legal herbalism therapy practice or herbal shop you need to pass two exams (usually preceded by a course with both theoretical and practical lessons) and gain government registered certificate. In case of a shop you also have to adhere to quire strictly controlled requirements based on what type of products you want to sell. If you want to grow and then sell herbs you have to obtain separate certificate (again by passing exams and complying with all requirements for your plantation and rest of the process) and grow them using seeds originating from government mandated sources.