Marijuana remains an illegal substance pursuant to the controlled substances act. Therefore, the United States Patent and Trademark office will NOT issue a federal registration, even for medicinal purposes. But, there are alternative ways of securing trademark rights for Marijuana and related goods or services.
Use and police your trademark in states where Marijuana is legal.
File for trademarks in states you do business or license your trademark(s).
Seek registration for goods or services related to marijuana, but that are not illegal. For example: CBD infused dietary and nutritional supplements or products derived from industrial hemp.
File for trademark protection in states where marijuana is legal and open for registration in that state.