· John Heider's Answer
· Hi Pauline-I noted the pruning information below that you can also find under the Tropicana Canna Lily plant file in Gardenality. Below is the link to this plant file if you would like other information also. Just click on the link to go directly to the plant file.
To prolong the blooming period you can remove dead flowers on canna lilies. Use sharp scissors or pruners to cut the flower stem down to an inch or so above the next node on the stem. This will prompt the flower stem to bloom again. When a flower stem has no buds left on it it can be cut to the ground if desired. After foliage has died completely back from frost you can cut it back to 4 inches above the ground. In cooler climates you can mulch for winter protection.
In zones north of 7b, rhizomes will need to be removed from the soil and stored for winter. Right after the plant has gone dormant, when the foliage has died back but the before the ground becomes frozen, dig the clumps out of the soil with a shovel. Remove most of the soil from around the rhizomes/ bulbs with your fingers. Cut off the dead foliage of each rhizome and then place them in a sheltered spot for a few days until they are thoroughly dry. Then wrap each bulb in newspaper and insert in a cardboard box or mesh bag. Space the rhizomes so they do not touch each other. Store the box in a room such as a garage with temperatures between 40 and 55 degrees Fahrenheit. Inspect the roots regularly and discard those that become rotted. http://www.gardenality.com/Plants/15/Perennial-Plants/Tropicana-Canna-Lily.html#Tab=Overview
Please ask if you have any other questions.