Canna (canna lily) is a genus of nineteen species of flowering plants. Canna is the only genus in the family Cannaceae. The species have large, attractive foliage and horticulturists have turned it into a large-flowered and bright garden plant. Although a plant of the tropics, most cultivars have been developed in temperate climates and are easy to grow in most countries of the world as long as they can enjoy at least 6–8 hours average sunlight during the summer, and are moved to a warm location for the winter. The flowers are typically red, orange, or yellow or any combination of those colours, the wild species often grow to at least 2–3 m in height but there is a wide variation in size among cultivated plants, numerous cultivars have been selected for smaller stature. Cannas grow from swollen underground stems, correctly known as rhizomes, which store starch, and this is the main attraction of the plant to agriculture, having the largest starch particles of all plant life.
Some species and many cultivars are widely grown in the garden in temperate and sub-tropical regions. Sometimes, they are also grown as potted plants. A large number of ornamental cultivars have been developed. Internationally, cannas are one of the most popular garden plants and a large horticultural industry depends on the plant. The rhizome of cannas is rich in starch, and it has many uses in agriculture. All of the plant has commercial value, rhizomes for starch, stems and foliage for animal fodder, young shoots as a vegetable and young seeds as an addition to tortillas. The seeds are used as beads in jewelry. In more remote regions of India, cannas are fermented to produce alcohol. A fibre obtained from the leaves is used for making paper. The leaves are harvested in late summer after the plant has flowered, they are scraped to remove the outer skin and are then soaked in water for 2 hours prior to cooking. The fibres are cooked for 24 hours with lye and then beaten in a blender. They make a light tan brown paper. A purple dye is obtained from the seed and a smoke from the burning leaves is said to be insecticidal. Cannas are used to extract many undesirable pollutants in a wetland environment as they have a high tolerance to contaminants. Cannas grow best in full sun with moderate water in well-drained rich or sandy soil and grow from perennial rhizomes but are frequently grown as annuals in temperate zones for an exotic or tropical look in the garden.
Offer (C. indica):