Answer: Well, what you're seeing is probably quite perplexing, but the truth of the matter is, Iris do not change color - it's simply a genetic impossibility. If your Iris are blooming in colors different than you'd expect, what is more likely to have happened is that your Iris are overcrowded. More vigorous varieties will tend to crowd out the less vigorous varieties. Give your Iris lots of space, and divide them every three or four years. When you divide them, be sure to dig up the entire clump, not leaving behind any new shoots that might get mixed in with your new varieties. Another possible explanation is that a chemical drift from a chemical spray (such as the weed killer Roundup) affected your Iris, possibly warping and damaging the flower and its color.
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