Hello :
Garden and Hardy are terms that have been used interchangably to describe a mum that will survive the winter and become perennial in our gardens. There are mums used in the floral industry that are not winter hardy and cannot be expected to survive. Most mums sold in the late summer and early fall should be hardy. The best way to get them established is to make sure you rough up the root ball very well and pinch or cut off the flower blooms soon after you plant them to encourage roots to allow the plant to survive our winter weather.