Canna edulis / QLD Arrowroot ‘Rojo’

How to Grow Canna edulis / Arrowroot

Canna edulis, also commonly known as Achira or edible canna, is a species of the Canna genus primarily grown for its large, starchy rhizomes. Native to the tropical and subtropical regions of the Americas, particularly the Andean highlands, Canna edulis has long been cultivated by indigenous peoples for its edible and utilitarian value.

Though taxonomically similar or synonymous with Canna indica in some classifications, Canna edulis is typically used to denote those cultivated forms specifically selected for food use, due to their larger rhizomes and high starch content.

Canna edulis is a robust, herbaceous perennial that grows from thick underground rhizomes.

• Height: Ranges from 1.5 to 3 meters
• Leaves: Large, paddle-shaped, often green but can be tinged with purple or bronze.
• Flowers: Bright and ornamental, usually red, orange, or yellow; while showy, they are secondary in importance to the plant’s rhizomes in food-producing varieties.
• Rhizomes: Thick, fleshy, and starchy; they can grow to substantial sizes and resemble those of ginger or turmeric.

Propagation and Growing Instructions

Canna edulis is propagated primarily through:

• Rhizome division: The most common method. Sections of the rhizome with at least one growing bud are planted directly.
• Seeds: Less common due to slow germination and variable traits, but viable. Seeds have a hard coat and benefit from scarification before planting.

1.     Planting is typically done at the beginning of the rainy season in tropical areas, or in spring in temperate climates. However this plant is very hardy, and can be planted year round if cared for.

2.     Space plants 30-100cm apart (depending how dense you want the planting) to allow for rhizome expansion and air flow.

3.     They will grow in any soil type. However, they enjoy moist, well-draining soil, rich in organic matter, with a neutral pH (6.6-7.3). It can tolerate heavy clay and waterlogged soils better than most root crops. Some rhizomes may develop above the soil. This is an indication the soil is poor and not to its liking.

4.     Water regularly when first establishing the plants. Once planted they are tollerent of dry periods. We also find they will put more energy into rhizome development during these periods.

5.     Apply a generous amount of organic mulch to retain moisture and suppress weeds.

6.     Plants require 6–10 months to mature, depending on climate and variety. The tubers are best harvested to eat when still small, about the size of a tennis ball and the skin is still white.  Young tubers have the best flavour; older ones are fibrous.

Uses in Permaculture

Canna edulis is highly valued in permaculture systems for several reasons:

1. Edible Rhizomes: Serve as a resilient, perennial starch source, especially in climates unsuitable for potatoes or grains.
2. Soil Improvement: The extensive root system helps prevent erosion and improves soil structure.
3. Biomass Production: Large leaves produce ample biomass for compost or mulch.
4. Water Management: Tolerant of waterlogged soils, it can be integrated into greywater systems or swales to help purify and manage water.
5. Polyculture Compatibility: Functions well in guilds, particularly alongside fruit trees, nitrogen fixers, and other perennials.

Culinary Uses

Some varieties eaten raw. Most are steamed, roasted, barbecued, diced finely, added to stir-fries, casseroles, stews, soups, in many meat or savory dishes. Some are ground down into a powder and used as a flour and thickening agent.  Does not possess a lot of flavor on its own, but absorbs flavours and makes a useful meal-extender.  Looks and tastes similar to potato.  Takes longer to cook, yet holds its shape.  Peel and cut into thin chips, add garlic salt and bake or fry until crispy and golden.  Wrap food in the leaves to steam, similar to banana leaves. 

• Boiled or Baked: When cooked, the texture is similar to potato or sweet potato, though it may be slightly fibrous.
• Canna Starch: The rhizomes are traditionally processed to extract a very pure starch known as arrowroot canna or achira starch. This is used in baking, thickening sauces, or making translucent noodles, especially in parts of Asia and South America.
• Fermented Products: In some cultures, rhizomes are used to produce alcoholic beverages or fermented foods.

Nutritional value:  Vitamins A, B1, B2, B3, B6, & C.  The tuber has a high potassium content and 1-3% protein.  The young leaves and shoots are nutritious and contain 10% protein.

The young shoots and sometimes the seeds are also used in cooking in various regions, although these are less common.