Canna lilies (also called cannas) are beautiful and very easy to grow, but they're not for the faint of heart. They are generally huge with large showy flowers, and when you grow them, you are making a visual statement with an exclamation mark. Cannas work well in pots and can be transplanted indoors or outdoors, using the plants' own rhizomes (underground roots). The rhizomes can also be stored for winter.
Canna leaves are wide and long, can have a wild stripe pattern, and their colors can range from yellow to orange to almost black and neon pink. Watching canna leaves shoot up and then unfurl over a few days is an impressive sight.
When and Where to Grow Cannas
Cannas are easy to plant. If you live in a climate that is zone 7 or warmer, you can grow cannas outside year-round. If you live in a cooler climate, you can either grow them inside in pots or you can plant them outside during the warm months and when winter hits, cut off the plants' rhizomes and bring them inside, where you can replant them in pots or store them for winter.
To store the rhizomes, shake off the soil and keep them in a damp medium in a cool (frost-free), dry place.
Cannas are large plants, so bigger is better. Choose a pot that is at between 15 and 18 inches in diameter. This is not only for aesthetic reasons; it also increases your chances for large healthy plants, and it prevents the pots from tipping over.
While it is possible to buy plants that are already growing, it is common to grow cannas from the rhizomes. To plant the rhizomes, place them 4 inches below the surface of the potting soil, making sure there are no air pockets and that they are surrounded by soil.
If you live in a cold climate (less than zone 7), you can start your cannas inside and move them outside once the overnight temperatures are consistently above 50 degrees.
Caring for Cannas
While cannas prefer full sun, they will survive in partial sun. They prefer to be kept on the moist side and don't like to dry out completely. Cannas need to be fertilized regularly, with either a slow-release fertilizer or a diluted liquid fertilizer.