Jan - wet conditions can help promote the rot since it gives the bacteria/virus (depends on kind of rot) a warm humid environment to grow in. Now I believe that newly planted iris can be more susceptible because they have already undergone the shock of being dug up and moved, and in most cases have been moved to new climates as well. That said, while I have had some rot this year, I have only completely lost four new rhizomes. The rest have been able to be treated and are growing new fans. Four out of over 250 is pretty good. I would like it to be zero out of 250, but we had a very wet time during planting.
As for Revved Up Rose, I would consider digging it up and soaking the roots in water for a few days (this also gives you a chance to check out the rhizome), then possibly putting it in a pot, or someplace where you can give it a bit more water and keep an eye on it. I had a couple of dwarfs and intermediates that looked to be goners, but extra water and care has rejuvenated them.
