Answer: Some mums change colors that way naturally as the blossoms age.
All newly planted mums require careful attention to soil preparation and watering or they may wilt. This is especially true, however, with those that are very potbound when purchased. In some cases, too, they are used to daily watering at the gorwers and it is difficult for them to adjust to growing under garden conditions.
For the above reasons some people consider mums to be the equivalent of cut flowers -- a pretty but ephemeral decoration. If you are planning to grow them as perennials your best bet is to purchase them as early in the season as possible (spring is best if you can find them) so they can become well established before undergoing the stresses of blooming and winter weather.
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