The canna family, Cannaceae, is comprised of one genus Canna and more than fifty species. Most gardeners choose canna plants for their colorful leaves and blooms to enhance their garden’s ornamental or decorative appearance.
Canna edulis, native to Central and South America, is the one species important to agriculture. The roots are rich in starch. It is commercially cultivated in Australia for a product called “Queensland Arrowroot” and in the Caribean for a thickening agent called “tous-les-mois”.
The rhizomes of Canna edulis are similar in taste to white potatoes if cooked, but because of their high content of fiber they are not as palatable. The green leaves and stalks are used as food for cattle.
Another highly appreciated species is Canna indica, called Ali’ipoe and Li’ipoe on the Hawaiian Islands. The ripe seeds are used for making Hindu and Buddhist rosaries in India and throughout Southeast Asia to count mantras,chants, or prayers. The leaves are used for food wrappings in tropical regions of Africa.
Other species include Canna glauca and Canna gigantea which are native to Brazil. Canna glauca is used as a cooked vegetable, and Canna gigantea is used as a diuretic. Canna speciosa is cultivated in the Sierra Leone and is used as a seasoning similar to turmeric.
Cannas flourish in most parts of the United States with plenty of heat, temperatures ranging from upper 70s to low 90s, and regularly watering. They are dependable and easy to grow providing tropical foliage and flowers from early summer until fall frost.
Cannas are available as dwarfs, one to two feet tall, medium height, three to four feet tall, and tall size plants, six feet or more.
Excellent dwarf varieties include Bangkok Yellow, Chinese Coral, Jester Pink, Japanese Rose, Orange Punch, Pink Angel and Porcelaine Rose.
Medium to tall size varieties include Aida, Cleopatra, North Star, Picasso, President, Red Futurity and Richard Wallace.
The foliage ranges in color from different shades of green to beautifully variegated leaves.
Cultivars with variegated foliage include Bangkok Yellow, Pretoria, Stuttgart and Tropicana.
Canna rhizomes should be started in spring indoors before planting them outdoors after all danger of frost has passed generally sometime in the month of May in most of North America.
Before planting outdoors, either in pots or in the ground, add some compost, manure or high Nitrogen slow release fertilizer to the soil in order to increase lush growth. Blood meal is an excellent choice when it comes to a slow release high Nitrogen fertizer.
Best results are achieved when cannas are planted in loose, fertile and well drained soil which has warmed to 60 degrees or more.
In the ground cana rhizomes should be planted approximately twelve inches apart. When grown in pots planting two rhizomes into one twelve inch pot results in a nice display of foliage and flowers. This is best achieved by placing two rhizomes with space in between them and the growing tips showing in opposite direction.
When planting outdoors in the ground, or in pots, the rhizomes are laid horizontally and completely covered with an inch or more of soil with the growing eye, if possible, facing upwards. However, this is not critical as cannas will always grow towards the surface, growing towards the light. During one growing season cannas produce three to five rhizomes for each rhizome planted.
Canna plants need regular watering and fertilizing with any fertilizer high in Nitrogen. Regular dead-heading of spent flowers results in an attractive floral garden display.
Cannas are rarely bothered by insects. If insects appear, several applications with insecticidal soap usually take care of the problem easily.
After the first frost the tops of the plants should be removed, cut off, and the rhizomes dug up for planting next spring. The rhizomes should be rinsed, the soil washed off, divided and dried.
One storage option is to layer the rhizomes with peat in cardboard boxes with lids or to place them in plastic bags with a few holes for a little ventilation. This way canna rhizomes can be stored in the basement, garage, or any place which is cool and stays above freezing. The ideal storage temperature for canna rhizomes is between fifty and sixty degrees.
Another storage method is to dig up the whole clump of rhizomes, without being cleaned off, cover them with plastic and store them in the same manner mentioned above. The rhizomes should never be stored in mesh bags as this results in the rhizomes drying out.
Cannas are wonderful plants to grow, either in the ground or in pots, and provide the gardener with great aesthetic appeal and appearance in the garden from early summer until fall frost.