As “fresh leaves” – no preserving, pickling, drying, etc., you would be prohibited from sending them to many parts of the world, as noted above. Even vacuum sealing would be disallowed unless your method of sealing would also kill or inhibit the growth of unwanted passengers. (For example, sending goods sealed in a pure nitrogen environment may be permitted – but you’d have to check with the various countries’ import requirements to be sure.)
This applies to foods as well as other “natural” organic products. You can’t even ship goods on “raw wood” pallets to the USA any more. The wood has to have been treated first to destroy the possibility of shipping unwanted insects or other pathogens to the port city.
Obviously, this is not a blanket prohibition, as the USA imports fresh foods from all parts of the world, and without restrictive packaging. Knowledge of the USDA requirements would help in shipping to the USA; I’m sure that other countries have their own restrictions and needs.