Canna lilies flower superbly through summer and their lush foliage makes them a must in any 'tropical' garden. They are traditionally grown like dahlias, lifting them after the frost has damaged the foliage and their roots needing frost protection in a box of dryish compost or peat. We find that if you a growing them in a pot it's easiest to just leave them in the pot, in an unheated greenhouse until new shoots appear in spring. When shoots appear they can be divided if required.
Don't forget Cannas are naturally bog plants so they need copious amounts of water & a lot of feeding in the growing season
