Where can i find crosnes in canada?

I have recently been researching a plant by the name stachys affinis aka chinese artichoke or crosnes also mint root ...it is a plant in the mint family that makes delicious little tubers underground that are like a tasty waterchestnut ...but i cannot seem to find them anywhere in canada or at least where they can be shipped to canada anyone have any idea where i can find them ?

This place in Eastern Ontario

http://www.nortonnaturals.com/product-p/ca.htm

Interesting, I have never heard of them.

I got mine from Mapple Farms, http://www.mapplefarm.com/

They've done great and have spread quite nicely for me over the years.