mailing plants between US and Canada

[Paul]

I know this topic must have come up at some point but I got tired of searching. Out of curiosity, would there be issues with mailing plants between US and Canada. In other words, are phytosans and all that rigamaroll still required. There are times I'd like to participate in plant trades with our Canadian neighbors, but I didn't know what the legality might be and would had to have a 'mountie' or US customs come knocking on my door ...