It is often forgotten that Cannaceae is a vegetable, that was turned into a garden cultivar by early horticulturists. Although originating only in the tropical and semi-tropical Americas, the genus is found all over the world. The early explorers did not take Cannas to Japan and China because they liked the foliage or flowers so much, but because it was a fast growing vegetable that filled their empty stomachs.
Canna tubers can be used all year round, as a potato substitute. Peel the tubers and cut them into chips, then bake in the oven until golden brown, the flavour is improved by a sprinkle of garlic salt. Cut into cubes they can then be added to soups, or steamed like potatoes, until tender. Young tubers have the best flavour, older ones are fibrous.
The flour keeps well and can be used as a thickener. To thicken to a light syrup use 2 level teaspoons of arrowroot to each cup of water, heat, stirring until thick.
The species grown mainly in Asia for food is Canna discolor. This is an interesting species, as not only does it grow very large rhizomes, but it is also the only Canna wild species that is seed sterile, indicating that it is a triploid, as stated by the premier authority, Dr Khoshoo, and confirmed by Dr Tanaka in his revision of the Canna species.