Richard, it's not the season for digging, planting, ordering or shipping irises right now. Now is the time for planning and making wish lists. Ordering takes place as early as January, February, or March. Digging should take place 6 weeks after bloom, if the vender knows what they're doing, so that is in July for TBs. Sales (for leftovers) can be expected in late August or September. Planting needs to be done while the soil is still warm enough for the rhizomes to establish a new root system before hard freezes begin. I don't think I'd plant past September unless I had a greenhouse.
If a vendor digs in May or even early June, he or she is doing so for his own convenience, and not thinking about getting you good rhizomes that will bloom next year. It takes 6 weeks after bloom for a new rhizome to develop new buds internally for next year. If you interrupt that process by digging them too soon, they may live, but the rhizomes will be underdeveloped and probably won't bloom the following spring. They will usually need another year or two before they bloom. At least I have always found this to be the case when vendors shipped to me too early. I keep track of such things.
