Answer: If your iris are blooming a different color than originally purchased, it is because of letting your iris go to seed: the bloom stalk was not removed shortly after blooming. Bees do a wonderful job of pollinating different colors for the following year. The dominant color of the iris will take over if the bloom stalk is not removed shortly after the bloom dries up. Chemical damage, overcrowding, and heat stress can be a factor in some color changes. They won't revert back once they have changed.
Peony buds that turn black are symptoms of a fungal disease called Botrytis Blight. Pick off the affected buds so the disease doesn't spread. There are several fungicides availble to protect your peony plants from this disease but they should be applied before you see the symptoms so apply according to label directions.
Best wishes with your garden.
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