Introduction
Growing canna lilies is one of the most rewarding ways to bring a touch of the tropics to your backyard. These architectural plants, with their paddle-shaped leaves and vibrant blooms, add height and drama to any garden bed. If you have been enjoying a beautiful patch of cannas, you might find yourself wanting more of them for other areas of your yard. The good news is that these plants are incredibly easy to multiply. At Longfield Gardens, we love how cannas can transform a landscape with minimal effort from the gardener.
Whether you are looking to share plants with a neighbor or simply want to fill a larger space, understanding how to handle their underground stems is key. Many gardeners refer to these as bulbs, but they are technically rhizomes—thick, fleshy stems that grow horizontally under the soil. This article will explain exactly how to cut and divide them to ensure your garden stays lush and colorful year after year.
Cutting canna lily rhizomes is a simple, effective way to rejuvenate your plants and expand your collection.
Understanding Canna Lily Rhizomes
Before you pick up your garden knife, it helps to understand what you are working with. While most people call them "canna bulbs," these plants actually grow from rhizomes. A rhizome is a specialized underground stem that stores energy for the plant. If you look at one closely, you will see it looks similar to a piece of ginger root.
Rhizomes grow outward over time, creating new shoots as they move through the soil. This is why a single canna planted in the spring can become a large, impressive clump by the end of summer. Because they store so much energy, these rhizomes are very resilient. They are designed to be divided, making them a perfect candidate for propagation.
The most important part of the rhizome is the "eye." These are small, often pink or white bumps on the surface of the fleshy root. These eyes are the points where new stems and leaves will emerge. When you ask if you can cut canna lily bulbs, the answer is a resounding yes, provided you ensure each piece has at least one of these vital growth points.
Why You Should Cut and Divide Cannas
There are several reasons why cutting your canna rhizomes is a great practice for any gardener. The most obvious reason is propagation. By cutting one large rhizome into several smaller pieces, you can turn one plant into five or six new ones. This is an affordable way to create a mass planting or a living privacy screen.
Another reason to cut them is to maintain the health of the plant. Over time, canna clumps can become overcrowded. When too many stems compete for the same nutrients and water, the blooms may become smaller, and the foliage might look less vibrant. Dividing the clump every two or three years keeps the plants vigorous.
Finally, cutting is often a necessary part of the "lifting" process for gardeners in colder climates. In regions where the ground freezes, canna rhizomes must be dug up and stored indoors for the winter. Cutting and storing canna rhizomes makes them much easier to pack into storage bins or crates.
The Best Time to Cut Canna Rhizomes
Timing is one of the most important factors in gardening success. For canna lilies, the best time to cut and divide the rhizomes is in the early spring, just before you plant them. At this time, the "eyes" are often starting to swell or even sprout slightly, making them very easy to identify.
If you live in a warm climate (USDA zones 8 to 11) where cannas stay in the ground year-round, you can divide them in late winter or very early spring before the new growth really takes off. For gardeners in cooler zones who store their rhizomes over winter, you can divide them either in the fall when you dig them up or in the spring before they go back into the ground.
Many people prefer the spring because it allows you to see which parts of the rhizome have come through the winter in the best condition. If a piece feels soft or looks shrivelled, you can simply discard it and only plant the firm, healthy sections.
How to Cut Canna Lily Bulbs Step-by-Step
Cutting canna rhizomes is a straightforward process. You do not need any specialized equipment, but a few basic tools will make the job easier. Here is how we recommend doing it for the best results.
Prepare Your Tools
Start with a clean, sharp knife or a pair of garden shears. Using a sharp blade ensures a clean cut, which helps the plant heal faster and reduces the risk of rot. It is also a good idea to wipe your blade with rubbing alcohol between plants. This prevents the spread of any soil-borne issues from one clump to another.
Lift the Clump
If your cannas are in the ground, use a garden fork or a shovel to gently lift the entire clump. Start digging about a foot away from the stems to avoid slicing through the rhizomes accidentally. Gently shake off the excess soil so you can see the structure of the roots.
Identify the Eyes
Look for the small, raised bumps or "eyes" on the rhizomes. These are often found near the ends of the segments. For a successful new plant, each piece you cut must have at least one healthy eye. However, leaving two or three eyes per piece will result in a faster-growing, fuller plant in the first season.
Make the Cut
Slice through the fleshy rhizome to separate it into sections. Each section should be about 3 to 5 inches long. If the clump is very large and woody, you may need to use a little more force, but usually, a sharp knife will glide right through.
Let the Cuts Heal
This is a small but important step. Once you have cut your pieces, let them sit in a dry, shaded spot for a day or two. This allows the cut surface to "callous" or dry over. A calloused surface acts like a scab, protecting the inner flesh of the rhizome from moisture and soil bacteria once it is planted.
Key Takeaway: Successful Division
- Always use a sharp, sterilized knife for clean cuts.
- Ensure every piece has at least one (preferably two) visible "eyes."
- Keep sections roughly 3 to 5 inches in length.
- Allow the cut ends to dry and callous for 24–48 hours before planting.
Identifying Healthy vs. Unhealthy Pieces
When you are cutting your canna bulbs, you might encounter some pieces that look a little different. It is important to know which ones are worth planting and which ones should be tossed in the compost bin.
A healthy canna rhizome should feel firm to the touch, similar to a fresh potato. The color is typically creamy white or light tan on the inside. If you see an "eye" that is starting to turn green or pink, that is a great sign of a healthy, active plant.
On the other hand, if a rhizome feels spongy or soft, it may have started to rot. These pieces are unlikely to grow and should be discarded. Similarly, if a piece is very small and has no visible eyes, it will not have the energy to produce a new plant. Focus your efforts on the thickest, healthiest-looking sections.
Planting Your New Divisions
Once your canna pieces have calloused over, they are ready for their new home. Whether you are planting them in garden beds or containers, the process is the same.
Cannas love the sun. For the most vibrant flowers and the tallest growth, choose a spot that gets at least six to eight hours of direct sunlight every day. They are also heavy drinkers, so while they need soil that drains well (meaning water doesn't sit in puddles), they do best in soil that stays consistently moist.
Plant the rhizomes about 4 inches deep. If you are planting several in a row, space them 12 to 18 inches apart. This might seem like a lot of space for a small piece of root, but remember that cannas grow very quickly! By mid-summer, those spaces will be filled with lush foliage. Position the rhizome horizontally in the hole with the eyes facing upward. For more detail, see this step-by-step canna planting guide.
Maintenance Pruning During the Summer
Cutting is not just for propagation; it is also a part of regular plant care. During the summer, you can use your shears to keep your cannas looking their best.
Deadheading for Continuous Color
"Deadheading" is the practice of removing spent flowers. When a canna flower begins to fade and wither, cut the individual flower stalk off. Be careful not to cut the entire main stem, as there are often more flower buds waiting to open just below the first one. Removing old flowers prevents the plant from putting energy into seed production and encourages it to keep blooming.
Removing Damaged Leaves
Canna leaves are large and can sometimes be damaged by strong winds or hungry garden visitors. If a leaf becomes torn, browned, or unsightly, you can cut it off at the base of its individual stem. This won't hurt the plant and will keep the entire display looking tidy and fresh.
Cutting Back for Winter Storage
In many parts of the United States, canna lilies are treated as "tender perennials." This means they can't survive a frozen winter in the ground. If you live in Zone 7 or colder, you will need to cut back the foliage and dig up the rhizomes for the winter. Check the Hardiness Zone Map if you are unsure about your growing zone.
Wait until the first frost of autumn has hit the plants. You will see the leaves turn brown or black almost overnight. This is the signal that the plant is going dormant. Once this happens, use your garden shears to cut the stems down to about 2 or 3 inches above the soil line.
After cutting the tops off, carefully dig up the clump. At this point, you can decide whether to cut and divide the rhizomes now or wait until spring. Many gardeners find it easier to store larger clumps and do the fine cutting in the spring when the eyes are more visible.
What to Do Next: Winter Preparation
- Wait for the first frost to blacken the foliage.
- Cut the stems down to 3 inches.
- Gently lift the rhizomes and shake off the soil.
- Store in a cool, dark, frost-free place (like a basement or garage).
Managing Growth and Removing Unwanted Plants
Occasionally, we hear from gardeners who have an area where cannas have grown a bit too well. Because they are so vigorous, a small patch can expand quite a bit over several years. If you find yourself needing to reduce the size of a canna bed or remove them entirely, cutting is your first line of defense.
If you are trying to remove a patch, start by cutting all the foliage down to ground level. Then, use a sharp shovel to dig up the rhizomes. It is important to be thorough. You might wonder if the thin, hair-like roots left in the soil can grow new plants. The answer is no. Only the thick, fleshy rhizomes with eyes can sprout new growth. However, even a small piece of rhizome left behind can start a new plant, so try to remove as much of the fleshy root as possible.
For those who want to keep the patch but just want it smaller, simply "edge" the clump. Use a spade to cut straight down into the ground around the perimeter of the area you want to keep. This slices through the outward-growing rhizomes. You can then dig up the pieces outside your "boundary" and give them away to friends or move them to a different spot.
Practical Tips for Growing Cannas
At Longfield Gardens, we want every gardener to feel confident in their ability to grow beautiful flowers. We maintain a trial garden to test our plants, and we have found that cannas are among the most reliable performers if you get a few basics right.
First, remember that cannas are tropical plants. They do not like cold soil. If you plant your cut rhizomes too early when the ground is still chilly and damp, they may sit idle or even struggle. Wait until the soil has warmed up to at least 60°F. In most regions, this is around the same time you would plant tomatoes.
Second, don't be afraid to feed them. Because they grow so much foliage and such large flowers in a single season, they appreciate a bit of help. Adding a layer of compost to the soil at planting time or using a balanced liquid fertilizer every few weeks during the summer will lead to spectacular results.
Finally, keep an eye on moisture. While cannas are quite tough once established, they produce the best "jungle" effect when they have plenty of water. If you are growing them in pots, you may need to water them every day during the hottest part of the summer. For compact container-friendly options, browse the Short Cannas collection.
Common Myths About Cutting Cannas
There are a few misconceptions about cutting canna lily bulbs that are worth clearing up. One common myth is that you must use a specific type of hormone powder on the cut ends to make them grow. While professional growers sometimes use fungicide powders to prevent rot, it is rarely necessary for the home gardener. Simply letting the cut "air dry" or callous for a day or two is usually more than enough protection.
Another myth is that if you cut a rhizome and it doesn't have a visible sprout, it won't grow. As long as there is a healthy "eye" (a small, raised bump), the plant will grow. It might take a week or two longer to break the surface of the soil than a piece that already has a green sprout, but it will get there!
Safety in the Garden
It is always good practice to keep the safety of your family and pets in mind. Canna lilies are generally considered non-toxic to dogs, cats, and horses according to the ASPCA. However, it is never a good idea for pets or children to chew on garden plants, as any plant material can cause mild stomach upset if ingested.
When you are cutting your rhizomes, keep the sharp tools out of reach and ensure any discarded pieces are placed in the compost or trash rather than left lying around where they could be a tripping hazard or a tempting "snack" for a curious puppy.
Conclusion
Cutting canna lily bulbs—or rhizomes—is a simple, empowering skill that every gardener can master. It allows you to take control of your landscape, whether you are expanding your garden, sharing plants with friends, or simply keeping your existing clumps healthy and vigorous. By following the easy steps of identifying the eyes, using clean tools, and allowing the cuts to callous, you ensure a successful start for your new plants.
We are here to help you succeed in making your yard more beautiful. At Longfield Gardens, we stand behind the quality of our plants and want you to enjoy the process of gardening as much as the final result. With a little bit of sun, some water, and the simple act of dividing your rhizomes, you can enjoy a tropical paradise in your own backyard every summer.
- Identify healthy rhizomes with visible "eyes."
- Use sharp, clean tools for every cut.
- Allow cut pieces to dry before planting.
- Wait for warm soil temperatures before putting them in the ground.
Cutting and dividing canna lilies is one of the easiest ways to multiply your garden's beauty. With just a few simple cuts, you can turn a single clump into a stunning landscape feature.
For more inspiration and high-quality flower bulbs, feel free to explore the canna collection and start planning your next garden project today!
FAQ
Can I cut canna lily bulbs while they are blooming?
While you can technically cut the rhizomes at any time, it is not recommended while the plant is in full bloom. Cutting the root system during the peak of the growing season can cause the plant significant stress, leading to wilted leaves and dropped flowers. It is best to wait until the plant is dormant in late fall or just waking up in early spring.
How many pieces can I cut one canna rhizome into?
You can cut a rhizome into as many pieces as there are "eyes." Each segment needs at least one eye to produce a new plant. However, for a stronger and faster-growing plant, it is often better to leave two or three eyes on each 3-to-5-inch piece of rhizome.
Do I need to put anything on the cut surface of the rhizome?
For most home gardeners, there is no need for special powders or chemicals. The most important thing is to let the cut pieces sit in a dry, shaded area for 24 to 48 hours. This allows the cut to form a callous, which is a natural protective barrier that prevents rot once the piece is buried in the soil.
Will the thin roots attached to the rhizome grow into new plants?
No, the thin, fibrous roots that grow out of the rhizome cannot create new plants. Only the thick, fleshy rhizome itself contains the growth points (eyes) necessary to produce new stems and leaves. If you are dividing or removing cannas, you can trim away these thin roots without harming the plant’s ability to grow.
