Edible Canna Varieties: Which Species Are Safe?
While many ornamental cannas brighten gardens, not all are cultivated for consumption. The most notable edible species is Canna edulis, also known as achira or Queensland arrowroot, which is a major food crop in some regions. Its rhizomes are particularly prized for their starchy content. Other species, like Canna flaccida (golden canna), also have known edible parts, but it is crucial to properly identify the plant before consumption. Conversely, some ornamental varieties may have small or inedible rhizomes, and foraging from unknown garden plants is a high-risk activity.
Edible parts of the canna plant
- Rhizomes (Tubers): The large, starchy, underground storage organs of certain canna species are the most commonly consumed part. They can be baked, boiled, or dried and ground into a gluten-free flour. The flavor and texture are often compared to taro or sweet potato.
- Young Shoots: The tender new shoots can be cooked and eaten as a green vegetable, similar to bamboo shoots. They contain protein and are a nutritious addition to a meal.
- Leaves: The large, tough leaves of the canna plant are typically not eaten but are used as a wrapper for cooking food, much like banana or corn leaves, especially in Latin American cuisine.
- Flowers: The vibrant flowers of some varieties are reportedly edible and can be used as a colorful garnish in salads, although they hold little nutritional value.
Nutritional Profile and Benefits
Edible canna, especially the rhizome, is valued for its nutritional properties. A nutritional evaluation of Canna indica rhizomes revealed it contains significant amounts of moisture, carbohydrates, protein, fiber, and minerals. The starch from canna, known as achira starch, is easily digestible and has been used in health and baby foods. It also contains resistant starch, which has been shown to improve intestinal health and may help regulate blood lipids.
Comparison of Canna Rhizome vs. Potato
| Feature | Canna Rhizome (Canna edulis) | Potato (Solanum tuberosum) |
|---|---|---|
| Starch Granule Size | Exceptionally large | Smaller granules |
| Primary Macronutrient | Starch (can be high in resistant starch) | Starch |
| Fiber Content | High fiber content in some species | Moderate fiber content |
| Texture | Can be mucilaginous when cooked | Floury or waxy, depending on type |
| Flavor | Similar to taro, sweet | Starchy, earthy |
| Cultural Use | Minor crop, traditional staple in Andes | Major global staple crop |
| Availability | Mostly niche or wild-foraged | Widely available commercially |
Safe Harvesting and Preparation Techniques
To safely consume canna rhizomes, proper harvesting and cooking are essential.
Harvesting the rhizomes
- Correct Identification: Ensure you are harvesting an edible species, such as Canna edulis, not an ornamental hybrid. When in doubt, do not eat it.
- Optimal Timing: Harvest the rhizomes before the plant flowers, as this is when the roots are most starchy. End of winter or early spring is often recommended.
- Digging: Carefully dig up the large rhizome clumps, making sure to avoid damaging the plant for regrowth if desired.
- Cleaning: Thoroughly wash the rhizomes to remove all dirt before preparation.
Preparing for consumption
- Baking: The best method for preparing the starchy roots is often long, slow baking, sometimes for 12 hours or more in traditional methods. When baked, they become translucent and sweet. The contents can then be scooped out from the slit root.
- Boiling or Mashing: Canna rhizomes can be boiled like potatoes and then mashed. This can help improve the texture and make them more palatable.
- Starch Extraction: For a gluten-free flour alternative, the roots can be ground or pounded and then soaked in water. The starch settles, the water is poured off, and the starch is dried.
- Young Shoots: To prepare the young shoots, treat them like any other green vegetable—they can be blanched, sautéed, or added to stir-fries.
Important Safety and Identification Considerations
Foraging requires a high degree of confidence in plant identification. Although canna is not a true lily and is non-toxic to pets, eating the wrong variety or improperly preparing edible types can still cause digestive distress. Many canna varieties are hybrids specifically bred for aesthetics, and their edibility has not been confirmed. Stick to recognized edible species like Canna edulis and avoid garden-variety cannas unless their edibility is known. A common mistake is confusing cannas with toxic plants, so always verify identification with multiple sources or an expert.
Conclusion
In conclusion, the question, "Are cannas edible for humans?" has a nuanced answer. While certain species, most notably Canna edulis, have a long history as a food crop with nutritious and digestible starch, not all canna varieties are safe to eat. The rhizomes are the primary edible part, but the young shoots and flowers of some species are also consumed. To ensure safety, it is imperative to correctly identify the plant, limit consumption to known edible species, and follow proper harvesting and cooking methods. Foraging should only be attempted with certainty, and ornamental garden cannas should generally be avoided for culinary purposes.
