Marc Emery is charged with selling marijuana seeds by mail order to customers in the U.S. (CBC)

Vancouver's most famous marijuana activist, Marc Emery, is finally on his way to the United States to serve a five-year prison term for selling marijuana seeds by mail to U.S. customers.

Emery's wife, Jodie, says the self-styled "Prince of Pot" was being driven from a Metro Vancouver jail to the Washington State border on Thursday morning to be handed over to U.S. authorities.

Jodie Emery says her husband will be held in a detention centre south of Seattle for about a week before appearing before a judge to plead guilty and begin his plea-bargained sentence.

She said she and other supporters of the outspoken advocate for the legalization of marijuana are planning a noon-hour rally outside his Vancouver store to protest the extradition.

Emery was arrested in 2005 for allegedly selling marijuana seeds over the internet from Vancouver to residents of the U.S., following an investigation by Canadian and U.S. police.

He made an agreement with U.S. prosecutors last year that he would plead guilty to one charge of drug distribution in exchange for a five-year sentence.

Under the terms of the deal, Emery is expecting to return to Canada to serve his sentence, according to his legal team.