Introduction
There is something undeniably rewarding about watching the bold, tropical foliage of a canna lily unfurl in the summer sun. These plants are the heavy hitters of the garden, providing architectural height and vibrant, saturated colors that make any backyard feel like a private island getaway. While most of us grow these stunning perennials for their dramatic blooms and oversized leaves, there is a fascinating secondary use for this plant that often surprises home gardeners.
Many people find themselves wondering about the thick, fleshy roots they handle each planting season and ask: are canna lily bulbs edible? The answer is a resounding yes. In fact, certain species of canna have been a staple food crop in various parts of the world for thousands of years. At Longfield Gardens, we love plants that offer both beauty and utility, and the canna lily is a prime example of nature’s versatility.
In this guide, we will explore the history of edible canna lilies, how they are prepared, and how you can grow them to ensure a healthy, vigorous plant. Whether you are a curious gardener or an aspiring permaculture enthusiast, understanding the edible nature of these plants adds a whole new layer of appreciation to your summer landscape. Canna lilies are a safe, nutritious, and historically significant food source that bridges the gap between the ornamental flower bed and the kitchen garden.
The History and Tradition of Edible Cannas
The story of the edible canna begins long before it became a favorite in American flower borders. While we often call them "bulbs," the part of the plant that grows underground is actually a rhizome—a thick, horizontal stem that stores energy. These rhizomes have been cultivated as a food source in the Andean regions of South America for millennia.
The specific species traditionally grown for food is Canna edulis, often referred to as "Achira" in Peru and Ecuador. Archaeological evidence suggests that Achira was one of the earliest plants domesticated in the Americas. It provided a reliable source of starch for ancient civilizations, long before the potato became the global superstar it is today.
In these regions, the rhizomes were typically roasted in underground pits or boiled. The high starch content made them an excellent source of energy. As trade routes expanded, the canna traveled to Southeast Asia and the Pacific Islands, where it became known as "Queensland Arrowroot." In these tropical climates, the plant thrived, and people began extracting its starch to create fine flours used in noodles, biscuits, and thickeners for soups.
Understanding the Difference Between Ornamental and Edible Varieties
When you browse the selection at Longfield Gardens, you will mostly find ornamental hybrids. These are bred specifically for their spectacular flowers—like the brilliant reds of 'Crimson Beauty'—or their striking foliage. While these ornamental varieties are technically edible and non-toxic, they aren't always the best choice for the dinner table.
Ornamental Cannas
These varieties focus their energy on producing large, showy blooms and unique leaf patterns. Because of this, their rhizomes tend to be smaller and more fibrous. If you were to cook an ornamental canna rhizome, you might find it a bit "woody" or tough compared to the varieties grown specifically for food. However, they are perfectly safe to handle and pose no risk if a curious pet or child takes a nibble.
Canna Edulis (Achira)
This species is the workhorse of the edible world. It produces smaller, less flashy flowers, usually in a simple red or orange hue. Instead of putting energy into petals, the plant focuses on developing massive, starch-filled rhizomes. These rhizomes stay tender for a longer period and have a much higher yield of usable starch.
Can You Eat Any Canna?
Strictly speaking, all members of the Canna genus are non-toxic to humans. If you have a healthy patch of cannas in your backyard, the rhizomes are safe to consume. The primary difference is simply the eating experience. For the best culinary results, look for plants labeled specifically as "edible canna" or "Achira," but don't be afraid to experiment with the rhizomes of your ornamental varieties during the fall harvest.
Key Takeaway: While all canna rhizomes are non-toxic and edible, varieties like Canna edulis are preferred for cooking because they are less fibrous and contain more starch than ornamental hybrids.
Canna Lilies vs. Poisonous Lookalikes
Before you head into the garden with a shovel and a recipe, it is vital to ensure you are actually growing a canna lily. In the world of gardening, common names can be very confusing. Many plants have "lily" in their name, but they belong to entirely different botanical families, and some are highly toxic.
The "True" Lily Danger
Plants in the Lilium (True Lilies) and Hemerocallis (Daylilies) families are very different from cannas. While daylilies are also edible, true lilies (like Oriental or Asiatic lilies) can be toxic to humans and are famously deadly to cats. Cannas are not true lilies; they are more closely related to ginger and bananas.
Calla Lilies (Zantedeschia)
This is the most common point of confusion. Calla lilies are beautiful, but they contain calcium oxalate crystals. If eaten, these crystals cause intense burning, swelling, and irritation in the mouth and throat. Calla lily "bulbs" look somewhat similar to canna rhizomes but are generally rounder and more tuber-like. Never eat anything labeled as a Calla Lily.
Iris Rhizomes
Some iris rhizomes can look like small canna rhizomes when they are dug up. Many irises are toxic and can cause severe stomach upset. Always keep your garden beds well-labeled so you know exactly which plant you are harvesting.
How to Be Certain
- Check the Leaves: Canna leaves are large, broad, and wrap around the stem, resembling a banana plant.
- Check the Flower: Canna flowers are asymmetrical and grow on tall stalks.
- Check the Growth Habit: Cannas grow from thick, segmented rhizomes that grow horizontally just under the soil surface.
What Does a Canna Rhizome Taste Like?
If you enjoy the flavor of root vegetables, you will likely find canna rhizomes quite pleasant. They don't have a strong, overpowering taste, which makes them very versatile in the kitchen.
Texture
When raw, a young canna rhizome is crisp and slightly watery, similar to a water chestnut or a jicama. As they are cooked, the starch gelatinizes. This results in a texture that is a cross between a potato and a parsnip. If the rhizome is older, it can become quite fibrous, so it is best to harvest the younger, outer portions of the clump for eating.
Flavor
The flavor is mild and slightly sweet. Some people describe it as having a faint hint of coconut or a very mild earthy sweetness like a sweet potato. Because the flavor is so subtle, it picks up the seasonings of whatever it is cooked with, making it an excellent addition to stews and stir-fries.
The Power of Starch
The most notable feature of the canna rhizome is its starch. Canna starch granules are among the largest in the plant kingdom. This makes the starch incredibly easy to digest. In many cultures, canna flour is the preferred choice for feeding infants or the elderly because it is so gentle on the digestive system.
Nutrients and Health Benefits
Adding canna rhizomes to your diet isn't just a fun garden experiment; it’s a nutritious choice. Because these plants are heavy feeders and grow vigorously, they pack a lot of energy into their storage roots.
- High-Quality Carbohydrates: Most of the calories in a canna rhizome come from complex carbohydrates. This provides a steady release of energy rather than a quick spike.
- Fiber: Even the "tender" parts of the rhizome contain beneficial dietary fiber, which aids in digestion and gut health.
- Minerals: Cannas are known to contain good levels of potassium, which is essential for heart health and muscle function. They also provide trace amounts of phosphorus and calcium.
- Gluten-Free: Canna starch is naturally gluten-free. In many parts of the world, it is processed into a fine white powder used to make gluten-free noodles and bread.
What to Do Next:
- Mark your edible canna varieties with garden stakes early in the season.
- Keep your plants well-watered to ensure the rhizomes stay plump and tender.
- Avoid using synthetic pesticides or systemic chemicals on any plant you intend to eat.
How to Harvest Canna Rhizomes for Eating
Harvesting cannas for the kitchen is very similar to the process of lifting them for winter storage. Timing is the most important factor for flavor and texture.
Wait for the End of the Season
The best time to harvest is in the late fall, just after the first light frost has "blackened" the foliage. This frost tells the plant to send all its remaining energy down into the rhizomes. However, if you live in a warm climate, you can harvest them anytime the plant has reached maturity (usually 4–6 months after planting).
Digging Carefully
Use a garden fork rather than a shovel if possible. Start digging about 12 inches away from the base of the stalks to avoid slicing through the rhizomes. Gently pry the clump upward. Canna rhizomes often grow in a dense, interlocking mat, so you may need to lift a large section at once.
Selecting the Best Pieces
Once the clump is out of the ground, shake off the excess soil. Look for the "new" growth. These are the smooth, lighter-colored rhizomes on the outer edges of the clump. These younger sections are the most tender and flavorful. The older, central part of the clump—the "mother" rhizome—is often too woody for eating but is great for replanting next year.
Preparing Canna Rhizomes in the Kitchen
Before you start cooking, you need to clean your harvest thoroughly. Since these grow in the dirt, they have many nooks and crannies that can trap soil.
Cleaning and Peeling
- Soak and Scrub: Soak the rhizomes in a bucket of water for 10–15 minutes to loosen the dirt, then use a stiff vegetable brush to scrub them clean.
- Trim the Roots: Use a sharp knife to trim away the small, hairy feeder roots.
- Peel: The outer skin of a canna rhizome can be a bit tough. Use a standard vegetable peeler to remove the outer layer until you see the crisp, white flesh inside.
Cooking Methods
There are several ways to enjoy your canna harvest, depending on the texture you prefer.
- Roasting: This is the most traditional method. Toss peeled chunks with olive oil, salt, and herbs, then roast at 400°F until tender and golden brown. Roasting brings out the natural sweetness of the starch.
- Boiling: You can boil canna rhizomes just like potatoes. Once soft, they can be mashed with butter and milk. Note that they will be slightly "stickier" than mashed potatoes due to the unique starch structure.
- Frying: Thinly sliced canna "chips" are a delicious snack. Fry them in a light oil until crispy and sprinkle with sea salt.
- Extraction (Starch): If you have a large harvest, you can grate the rhizomes into a bowl of water, strain out the fiber, and let the starch settle to the bottom. Once dried, this powder can be used as a high-quality thickener for sauces.
Growing Canna Lilies for Beauty and Bounty
To get a good harvest of edible rhizomes, you need to grow a healthy, vigorous plant. Cannas are not fussy, but they do have a few "must-haves" to perform their best. We recommend following these simple steps to ensure your plants thrive.
Sunlight and Temperature
Cannas are tropical plants at heart. They crave full sun—at least 6 to 8 hours of direct light per day. They also love heat. In most regions, you should wait to plant your rhizomes until the soil has warmed to at least 60°F. If you plant them too early in cold, soggy soil, the rhizomes may sit dormant or, in worst-case scenarios, rot.
Soil and Space
These plants are "heavy feeders," meaning they need plenty of nutrients to grow those massive leaves and roots. Before planting, enrich your soil with plenty of compost or well-rotted manure. Space your rhizomes about 12 to 18 inches apart. This gives each plant enough room to expand its root system without competing too much with its neighbors.
Watering for Success
Because cannas produce so much foliage, they lose water quickly through transpiration. They are very thirsty plants! To grow large, juicy rhizomes, keep the soil consistently moist. In the heat of summer, you may need to water them deeply several times a week. A layer of mulch around the base of the plants will help hold moisture in the soil and keep the roots cool.
Depth Matters
Plant your rhizomes horizontally about 2 to 4 inches deep. If you see "eyes" (growth points) on the rhizome, try to point them upward, though cannas are resilient and will usually find their way to the surface regardless of which way they are facing.
Managing Pests and Care Naturally
If you plan on eating your cannas, it is best to manage the garden using natural methods. Fortunately, cannas are generally very hardy and suffer from few pests.
Canna Leaf Rollers
In some parts of the US, the canna leaf roller (a small caterpillar) can be a nuisance. They knit the leaves together before they unfurl. Instead of using harsh sprays, you can often manage these by simply hand-picking them or using a biological control like Bacillus thuringiensis (Bt), which is a naturally occurring soil bacterium that targets caterpillars but is safe for humans and pets.
Deadheading
To keep your plants looking their best and to encourage more flowers, "deadhead" the spent blooms. Cut the flower stalk down to the next leaf node once the blossoms fade. This prevents the plant from putting energy into seed production and keeps that energy focused on the roots—which is exactly what you want for an edible harvest!
Overwintering Your Cannas
In most of the United States (Zones 3-7), cannas will not survive the winter in the ground. If you want to keep your plants for next year—either for eating or for blooming—you must lift them. Overwintering cannas is a straightforward way to protect the rhizomes.
After you have harvested the pieces you want to eat, take the remaining "mother" rhizomes and clean them. Let them air dry in a cool, shaded spot for a day or two to let the skin toughen up. Store them in a cardboard box filled with slightly damp peat moss or vermiculite. Keep the box in a cool, dark place (like a basement or crawlspace) where temperatures stay around 40–50°F. Check on them once or twice during the winter to make sure they haven't dried out completely; if they look shriveled, a light misting of water will perk them up.
In warmer zones (Zone 8 and south), you can often leave your cannas in the ground year-round. Just cut the stalks back to the ground after the first frost and apply a thick layer of mulch to protect the rhizomes from any unexpected deep freezes. See this guide to leaving canna bulbs in the ground over winter for more information.
Conclusion
The canna lily is much more than just a pretty face in the garden. Its journey from a prehistoric Andean food staple to a modern ornamental favorite is a testament to its resilience and utility. While we often prize them for their "wow factor" in the landscape, knowing that these plants are also a source of nutritious, gluten-free starch makes them an even more valuable addition to the home garden.
By choosing the right varieties, ensuring they have plenty of sun and water, and following safe identification practices, you can enjoy the best of both worlds. Whether you are roasting the rhizomes for a unique side dish or simply enjoying the tropical shade of their massive leaves, the canna lily is a plant that truly gives back.
- Edibility: All canna rhizomes are non-toxic, but Canna edulis is the best for eating.
- Safety: Never confuse cannas with toxic "lilies" like Calla Lilies or True Lilies.
- Culture: Give them full sun, lots of water, and rich soil for the best root development.
- Harvest: Dig rhizomes in late fall and choose the young, outer growth for the kitchen.
Ready to add some tropical flair and a bit of history to your yard? We invite you to explore the vibrant world of canna lilies and discover why they remain one of the most beloved plants for gardeners across the country.
FAQ
Are all parts of the canna lily plant edible?
While the rhizome is the most commonly eaten part, the very young, unfurled leaves can also be cooked and eaten as a green, similar to spinach. The young seeds can be ground into a meal, but they become extremely hard as they mature (historically used as "Indian Shot" for jewelry or even musical instruments), so they are best avoided once they turn black.
Can I eat canna lilies bought from a garden center?
If you purchase plants from a garden center or a supplier like us at Longfield Gardens, the plants themselves are non-toxic. However, you should check if the nursery used systemic pesticides, which are absorbed into the plant’s tissues. If they did, it is best to grow the plant for one full season in your own garden without those chemicals before harvesting the new rhizomes for food. For current order details, see the Longfield Gardens shipping information.
Do I need to cook canna rhizomes, or can I eat them raw?
You can eat young canna rhizomes raw; they have a pleasant, crunchy texture similar to a water chestnut. However, they are much more commonly eaten cooked. Cooking helps to break down the starch and soften the fibers, making them much more tender and easier to digest.
Is canna starch the same as arrowroot powder?
Real arrowroot powder usually comes from a different plant called Maranta arundinacea. However, canna starch is often sold under the name "Queensland Arrowroot." They function very similarly in the kitchen as gluten-free thickeners, but they come from two different botanical sources. Canna starch is unique for its exceptionally large starch granules.
