No need. If you want to-if they are in a front garden, or something, go ahead. But otherwise, they will die back and you can clean them up in spring. You will see the new growth close to the ground, early in spring.
I am disappointed in my garden mums for the second year in a a row. I plant them and they only flower a bit after I buy them then nothing. They stay puny little things that I can't see. Next year I am going to stay with violas and pansies.
Most of the plants you buy in bloom have been greehouse forced and are off their normal schedule for flowering. You won't get a long lasting bloom in garden plants till the following Fall when they have resumed their natural schedule.