Melvin. Like said in previous posts, iris don't change color. If two irises are planted close together after a couple years, they might get mixed together and if one is stronger it can overpower the other one and take over smothering the weaker one out. There won't be any Mixed blends of the two unless they cross pollinated, and produced seeds that grew up into a new cultivar. If you dead head the blooms after they are spent, you won't have to worry about that happening.