You can absolutely grow phasion variegated canna lilies in pots. Choose a pot at least one foot tall-larger pots will allow the canna lilies to grow larger. Use a rich potting soil, and be sure to keep your cannas watered well. Phasions are the perfect "thriller" for containers, and allow those planters to stand out on patios or in entryways. Container planting is the preferred method for many gardeners in Zones 3 through 7, where canna lilies need to be lifted or stored each year. Cannas are not cold-hardy, and will not survive a hard frost. Instead of lifting, potted canna lilies can be brought inside and stored over winter. Potting also allows you to grow cannas indoors, to bring some of that summertime beauty in. In order to successfully keep potted cannas indoors, you will need to provide your cannas with a dormant period. If kept "awake" over winter, these plants don't thrive. In winter, store your potted cannas in a cool, dark location. Water just frequently enough that the soil doesn't dry out entirely. In spring, you can reintroduce them to a sunny location or windowsill.