Potted mums, or chrysanthemums, that are purchased for indoor use can be planted outdoors during or at the end of a growing season. However, mums sourced from a florist should be regarded as an annual rather than a perennial.
In areas where there is a definite winter, indoor variety mums will only survive outdoors if they are a hardier variety. Whereas mums from a florist will probably not survive a winter outdoors, chances are increased with varieties that are sold as decorative plants in early to mid autumn. Even so this latter variety has to be protected and preferably planted along a south wall, away from cold winds, to increase the chances of survival.