Canada postal will hopefully explain it to you better but be ready for a disappointment To the best of my knowledege the plant needs to be inspected and declared by Canadian costumes it needs to be, pest & disease free filling the Canadian costumes standards not the postal office standards

Why the hold up :Living plants into Canada from a marketer in U.S. may require an import stamp somewhere on the receiving end. The import stamp for cultivated living plants is kind of pricey but you could have someone with one pick it up for you ( an additional fee may also apply as imported plant stamp holder may require).