Canna Australia bulbs are not winter-hardy in colder climates, so it's important to provide proper care during the winter months. Canna bulbs in general are winter hardy in USDA hardiness zones 7-10. Add an extra layer of mulch in the wintertime.
In zones below zone 6, you must dig up the Canna Australia rhizomes
• As the first frost approaches, cut back the foliage to about 6 inches above the ground.
• Carefully dig up the rhizomes, shake off any excess soil, and allow them to dry for a day or two.
• Store the rhizomes in a cool, dark place (40-50°F, or 4-10°C) in a ventilated container filled with slightly moist peat moss, vermiculite, or perlite.
• Check on the rhizomes periodically throughout the winter to ensure they remain firm and free of mold or rot.
• Replant the bulbs in the spring following the planting guidelines mentioned above.