While there are many garden canna varieties with fiery red flowers, the red canna (Canna indica) usually pertains to a wild species. Also known botanically as Canna edulis, according to "Tropical Flowering Plants," its red flowers can be variable in color intensity. It produces seeds that drop and sprout, making it a weedy plant where warm climate and moist, fertile soils dominate. This canna is also called Indian shot and arrowroot canna.
Red canna's precise native range is obscure because it is widely naturalized and cultivated. It is known to have origins in the tropical areas of Central and South America.
Growing from a fleshy, starchy rhizome root, red canna develops firm and fleshy stalks with paddle-like green leaves. Some plants may have bronze, reddish or purplish foliage and stems. Depending on length of growing season, plants grow 3 to 6 feet tall. Atop the stalks appear a loose-clustered spike of red flowers, each with six petals around a tiny floral tube that is pollinated by hummingbirds, bees and butterflies. Considerable variation exists in flowers among plants, as the petals may range from blood red to orange or yellow streaked with red. After pollination, a rounded, prickly seedpod forms and dries to release small black seeds that are uniformly round.
Red canna is an attractive perennial wildflower for moist to wet garden locations such as at the edge of a freshwater pond. The rhizome root is edible after being cooked, eaten like potato or plantain. If the cooked root is strained to remove the fibers, dry powdered arrowroot is made. This flour is more easily digested and can be used to make quick breads. The black seeds can be made into jewelry, rosaries and, according to Wayne's Word, they may have been used in blunderbuss guns when lead pellets were lacking during the days of trade-ship piracy. This is where the name "Indian shot" has its origins.
Plant red canna in any moist to soggy soil that is warm and exposed to abundant sunshine, no less than six hours of direct sunlight daily. The branching rhizomes can be planted in mud in shallow water that is no deeper than 3 inches. Seasonal droughts will force the plants into a dormancy, as will a killing frost in autumn if planted outdoors. The rhizomes are not overly resilient to cold, and thus can be kept outdoors in the ground only in U.S. Department of Agriculture hardiness zones 8 and warmer. Elsewhere, lift the rhizomes and store indoors to plant outdoors the next spring when danger of frost has passed. Cannas grow more quickly when soils are rich in organic matter and temperatures are warm to hot.
Other Red Cannas
While this particular species is referred to as the red canna, many modern hybrid cannas derived from many different species bear red flowers that are much larger in size. These plants have the same growing requirements. Some variety names that produce red flowers include: Endeavour, Roi Humbert (also called Red King Humbert), President, Black Knight, Brandywine, Crimson Beauty, Firebird, Tropicanna Black, Phil's Scarlet Beauty, Red Dazzler, Red Futurity and Tropical Red.