Tom -- that is one thing that I don't keep track of -- when cultivars bloom. So -- I have to rely on memory, and I think we've established that my memory is crap!!
Copatonic blooms earlier than Rustler. But -- Copatonic is out in full sun in the fenceline bed -- Rustler is in the shady garage bed. So -- not sure my data is valid.
Bonnie -- there aren't too many Irises of that color -- if you like them both, I think your idea of one in front and one in back is a good one!!