Actually, technically speaking, you need a license to sell any kind of plant if your sales are over $100 a year. You get it from your state department of agriculture. Any retail store selling any kind of a plant, even cut flowers needs a license. In Oregon you can not even sell produce or flowers at a flea market without a state license. The rules and cost of the license may vary somewhat from state to state. If you buy any plants from outside this country, you need an import license specifically for plants that you get from the USDA.