evelyninthegarden said:
........... All in all, it seems as though Timothy should have nothing but wonderful results with his many irises. 
ah, I only wish that were true. Even tho the native soil profile supports good iris culture, it still needs to be amended with organic material, supplemental irrigation in the summer, and nutrients for best results here. The main enemies of iris here are botrytis/gophers and the sneaky back door arctic fronts that creep over the rockies and bone chill us without warning.
Part of my problem during the winter of 2016-17 was that we had a fairly mild fall, then followed by a sudden arctic plunge that dropped temps to zero and below with no snow cover. Those kind of temps we see only once every 20-30 years here. Plus we face daily winter challenges such as frequent wide variations in diurnal temp swings and occasional flooding in the fall and winter months causing fissures in the large rhizomes that we can grow here, thus leaving the gateway open for all kinds of rots, molds, and insect pests.
I assure you, iris can handily fail here without too much trouble. Take a look at my iris replacement list in my profile and you'll see -- lol Even tho it seems that conditions are near ideal in my locale, there are struggles that we have to overcome that are unique to our region
