They are hardy where I am, further east of you in eastern Ontario and USDA Zone 4a. However, I gave up growing the few that I had because of the iris borer.
Some of mine came from other gardens, some in pots from a local nursery. You could try asking the Ontario Iris Society if you want specific cultivars from a specialty grower, otherwise try garden centres locally or maybe someone else on ATP in Canada can help you out.
Ontario Iris Society:
https://sites.google.com/site/...
Forgot to say welcome to ATP!
