Latest date to order iris by zones:
Zones 0a - 3b ~ July 31
Zones 4a - 5b ~ August 15
Zones 6a - 9a ~ September 1
Zones 0a - 3b ~ July 31
Zones 4a - 5b ~ August 15
Zones 6a - 9a ~ September 1
Plant Hardiness Zones of Canada (click on the link to find your planting zone)