Canna plants, popular since Victorian times for their tropical foliage, feature striking flowers and large leaves similar to banana plants. Individual leaves reach up to 6 feet long and appear in shades of bronze, green, blue-green, burgundy and variegated. Canna plants reach up to 5 feet tall, though dwarf varieties only reach about 2 feet tall. Canna flowers appear in shades of pink, red, orange or yellow, depending on the variety. Tall, exotic and colorful, canna plants thrive throughout the United States, though they require special winter care in cooler climates.
Plant cannas during early spring, just after the danger of frost has passed. Select a planting location that receives full sunlight and consists of moist, well-drained soil. Space canna plants 18 to 24 inches apart to allow room for their mature size.
Water once every 10 days during spring, summer and fall to keep the soil from drying out completely. Increase the frequency of watering to once per week during periods of dry weather. Soak the soil surrounding the plant to a depth of 4 to 5 inches at each watering.
Feed canna plants twice per year, once in spring and again during mid-summer, using a balanced 10-10-10 NPK fertilizer. Apply following the manufacturer's instructions for the best results and water lightly after application to prevent root burn.
Remove dead or faded canna flowers whenever possible to increase the appearance and health of the plant. Pinch off the old blossoms by hand near where they meet the stem to reduce damage to the plant and ease the process of re-blooming.
Cut back canna plants to ground level after the first heavy frost of fall, using garden shears. In zones cooler than 8, dig up the rhizomes with a shovel and pack in a container of garden soil. Store in a well-ventilated room for the duration of winter. Replant the rhizomes the following spring, after the risk of frost has passed.