Caring for Canna Lily in winter - Cut plant down to just above the soil Move to a cool area (50 degrees or so) for 10-14 weeks where it is dry. Then move back outside and water. OR Dig up lily after the first frost, remove soil and allow to dry. Store in a box of peat moss or newspaper over the winter. In spring plant with nubby side up. Divide the rhizomes when planting to propagate new lilies!