Introduction
There is nothing quite like the sight of a lush canna lily standing tall in the summer sun. With their oversized, tropical leaves and vibrant flowers, these plants bring a sense of high-summer energy to any garden or patio. At Longfield Gardens, we believe every gardener should experience the joy of watching a single rhizome transform into a magnificent, flowering focal point.
If your cannas have become a bit crowded or you simply want to expand your collection for free, it is time to learn about separating them. This process is rewarding and much simpler than many people realize. It allows you to refresh your existing plants while creating brand-new ones to tuck into other corners of your yard.
In this guide, we will walk you through the timing, tools, and steps needed to divide your canna rhizomes successfully. Whether you are a beginner or a seasoned pro, you will find that a little bit of maintenance goes a long way. Properly separating canna bulbs is the best way to maintain plant vigor and ensure a spectacular floral display year after year.
Understanding Canna Rhizomes
Before you start digging, it helps to understand what you are looking at. While most people refer to these plants as "canna bulbs," they are technically rhizomes. A rhizome is a thick, fleshy underground stem that grows horizontally just beneath the soil surface.
Unlike a true bulb, which is a self-contained "suit-case" of nutrients like an onion, a rhizome acts like a battery. It stores energy and sends out new growth points along its length. These growth points are often called "eyes." They look like small, swollen bumps or pointed nubs on the surface of the rhizome.
Each eye has the potential to become a new leaf and a new flower stalk. When you separate cannas, your goal is to cut the larger mass into smaller sections, making sure each piece has at least a few healthy eyes. This gives each new plant the best possible start when it is time to grow.
Why You Should Separate Your Cannas
Cannas are vigorous growers. Under the right conditions, a single rhizome planted in the spring can double or triple in size by the end of one growing season. Over three or four years, those individual pieces knit together into a dense, heavy mat.
Promoting Better Flowering
As the clump becomes overcrowded, the plants have to compete for water, nutrients, and space. You might notice that the stems are getting thinner or the flowers are smaller than they used to be. Separating the clump gives the remaining rhizomes room to breathe and access more resources. This leads to taller stems and more impressive blooms.
Keeping Plants Healthy
Good air circulation is important for garden health. When canna foliage is too packed together, moisture can get trapped between the leaves. Dividing the plants helps maintain a healthy balance of foliage and airflow. It also allows you to inspect the rhizomes and remove any old, woody, or unproductive sections.
Expanding Your Garden
One of the best things about separating cannas is that it is a free way to get more plants. If you started with one "Pretoria" or "Wyoming" canna, after a few seasons of dividing, you could have enough to fill an entire border or several large containers. It is a wonderful way to create a cohesive look throughout your landscape without spending more money.
Key Takeaway: Separating cannas refreshes the plant’s energy, prevents overcrowding, and provides you with extra plants to share or transplant.
The Best Time for Separating Canna Bulbs
Timing is everything in gardening, but with cannas, you actually have two great opportunities to divide them. The best choice often depends on your local climate and how you plan to overwinter your plants.
Dividing in the Fall
If you live in a region where the ground freezes (USDA zones 3 to 7), you will likely be digging up your cannas to store them for the winter. You can learn more about this process in Longfield Gardens’ guide to digging up and storing canna bulbs. This is a very common time to separate them. Once the first frost has blackened the foliage, you can lift the entire clump.
Many gardeners prefer dividing in the fall because the rhizomes are already out of the ground. It is easy to clean them off, see where the growth points are, and cut them into manageable pieces before putting them into storage. This saves space in your storage bins and means you are ready to plant as soon as the soil warms up in the spring.
Dividing in the Late Winter or Spring
Another popular option is to wait until late winter or very early spring, just before you plant them back out. If you store the entire clump over the winter, the "eyes" often become more prominent as the plant starts to wake up.
By waiting until spring, you can clearly see which parts of the rhizome are the healthiest and most ready to grow. If any part of the clump didn't survive the winter storage, you can simply cut it away and focus on the firm, viable sections.
Signs Your Cannas Need Attention
If you aren't sure if it’s time to divide, look for these clues during the growing season:
- The center of the clump looks sparse or has stopped flowering.
- The rhizomes are pushing up out of the soil or pressing against the sides of a container.
- The foliage looks stunted despite regular watering and fertilizing.
- You haven't divided the plants in more than three years.
Essential Tools for the Job
You do not need fancy equipment to separate cannas. Most of the tools are likely already in your garden shed. Having the right tools on hand makes the process faster and safer for both you and the plants.
- Garden Fork or Spade: A sturdy garden fork is often better than a shovel for lifting cannas because it is less likely to slice through the rhizomes accidentally.
- Sharp Knife: A serrated garden knife or a clean kitchen knife is perfect for making precise cuts. Avoid using blunt tools that might crush the fleshy tissue.
- Hose with a Spray Nozzle: You will need to wash away the soil to see the eyes clearly.
- Pruning Shears: These are helpful for trimming away old stems or dead roots.
- Gloves: Canna rhizomes can be muddy and a bit rough, so a good pair of gardening gloves will keep your hands protected.
- Disinfectant: A quick wipe of your blade with rubbing alcohol or a mild bleach solution between clumps helps keep everything sanitary.
How to Lift Canna Clumps Safely
Before you can separate the bulbs, you have to get them out of the ground. If your cannas are in the garden, start by cutting the foliage back to about 3 or 4 inches above the soil line. This gives you a "handle" to hold onto and gets the bulky leaves out of your way.
Place your garden fork about 6 to 12 inches away from the base of the stems. You want to dig wide to avoid stabbing the rhizomes. Gently rock the fork back and forth to loosen the soil. Work your way all the way around the plant until the entire clump feels loose.
Slowly lift the mass out of the ground. Canna clumps can be surprisingly heavy, especially if the soil is wet, so be sure to lift with your legs and not your back. If the clump is too large to lift at once, you can sometimes use your spade to slice it into two or three large chunks while it is still in the hole, then lift them out individually.
What to do next:
- Clear a flat workspace, like a potting bench or a tarp on the grass.
- Shake off as much loose soil as possible by hand.
- Use a hose to wash away the remaining dirt until the individual rhizomes are visible.
- Trim away any long, stringy roots that are in your way.
Step-by-Step Guide to Separating Canna Bulbs
Now that your canna clump is clean and visible, you can start the actual separation. Don't be intimidated by the dense tangle of roots; cannas are very resilient and tolerate division well.
Step 1: Inspect the Clump
Look for the natural "joints" in the rhizome. You will notice that the clump is made of several thick, finger-like sections joined together. Identify the "eyes" or growth points. These are the small, often pinkish or white nubs that look like the eyes on a potato.
Step 2: Make Your Initial Cuts
Using your sharp knife, cut through the fleshy bridges that connect the rhizome sections. Aim to create pieces that are about 3 to 5 inches long. Every piece you save must have at least two or three healthy eyes. While a piece with a single eye can grow, having multiple eyes ensures a fuller plant with more stems in its first season.
Step 3: Clean Up the Sections
As you work, you might find sections of the rhizome that feel soft, hollow, or look shriveled. These are usually old parts of the plant that have already done their job. Use your knife to trim these away and discard them. You want every piece you keep to be firm and solid, like a fresh ginger root.
Step 4: Let the Cuts "Cure"
This is a small but important step. Once you have finished cutting, let the individual rhizome pieces sit in a dry, shaded area for a few hours or even overnight. This allows the cut surfaces to "callous" over. A calloused edge is much less likely to rot once it is put into soil or storage.
Step 5: Sanitize (Optional but Recommended)
If you have had issues with rot in the past, you can dip the cut ends into a bit of powdered sulfur or a very diluted bleach solution (one part bleach to ten parts water). This helps protect the fresh tissue from soil-borne fungi. For most home gardeners with healthy plants, simply letting the pieces air-dry is sufficient.
Storing Divided Cannas for the Winter
If you are separating your cannas in the fall, you will need to store them properly until spring. The goal of storage is to keep the rhizomes dormant—not so wet that they rot, but not so dry that they shrivel up completely.
At Longfield Gardens, we recommend using a breathable medium for storage. Peat moss, vermiculite, or slightly damp sawdust all work well. Place a layer of the medium in a cardboard box or a plastic bin with air holes. Lay the rhizome pieces on top so they aren't touching, then cover them with more medium.
Store the containers in a cool, dark place that stays between 40°F and 50°F. A basement, crawl space, or insulated garage is usually perfect. Check on them once a month. If the rhizomes look shriveled, mist the storage medium with a tiny bit of water. If any look soft or moldy, remove them immediately to protect the rest.
Replanting Your New Canna Divisions
When the weather warms up and the danger of frost has passed, it is time to get your divided cannas back into the garden. In most parts of the US, this is late May or early June.
Choosing the Right Spot
Cannas are sun-lovers. To get the best leaf color and the most flowers, choose a spot that gets at least 6 to 8 hours of direct sunlight. They are also heavy drinkers, so they appreciate soil that stays consistently moist. If you have a low spot in the garden that stays a bit damp, cannas will likely thrive there.
Soil Preparation
Before planting, we suggest mixing some compost or well-rotted manure into the soil. This provides the slow-release nutrients that cannas need to fuel their rapid growth. If your soil is very heavy clay, adding organic matter will also help with drainage so the rhizomes don't sit in stagnant water.
Planting Depth and Spacing
Dig a hole about 4 inches deep. Lay the rhizome in horizontally with the eyes facing up. If you can't tell which side is up, don't worry—the plant will figure it out! Cover the rhizome with 2 to 3 inches of soil.
Space your new divisions about 1 to 2 feet apart. It might look like a lot of empty space at first, but remember that these small pieces will grow very quickly. By mid-summer, they will fill in the gaps to create a lush, seamless wall of color.
Key Takeaway: Success starts with soil temperature. Wait until the soil is at least 60°F before planting your divisions for the fastest growth.
Caring for Cannas After Division
Your newly separated cannas will need a little extra attention during their first few weeks in the ground. Because they have been cut and moved, they need to re-establish their root systems before they can focus on top growth.
Watering Correctly
Water the area thoroughly right after planting to settle the soil. Keep the soil consistently moist but not soggy. Once you see green shoots poking through the surface, you can increase the frequency of watering. During the heat of summer, cannas in containers may need water every day.
Feeding Your Plants
Because cannas grow so much foliage in a single season, they are "heavy feeders." Use a balanced, water-soluble fertilizer every few weeks once the plants are about a foot tall. This will support both the dramatic leaves and the bright flower spikes.
Mulching
Applying a 2-inch layer of mulch around the base of the plants is a great idea. Mulch helps hold moisture in the soil and keeps the roots cool. It also prevents weeds from competing with your young canna starts. Use bark chips, straw, or shredded leaves.
Common Varieties to Divide
While the process of separating canna bulbs is the same for all types, some varieties are especially popular for their reliable growth and ease of division.
- Tropicanna: Known for its extraordinary multi-colored leaves (stripes of gold, red, and green) and bright orange flowers. It is a vigorous grower that produces many offshoots.
- Wyoming: A classic choice with dark, bronze-purple foliage and large tangerine-colored blossoms. Its rhizomes are usually quite thick and easy to handle.
- Pretoria (also known as Bengal Tiger): This variety features striking yellow and green striped leaves. It adds a bright, luminous quality to the garden and divides very cleanly.
- Phaison: This variety is famous for its pink and orange variegated foliage. It is slightly more compact but still produces plenty of rhizomes for sharing.
- Cannas for Containers: If you are growing dwarf varieties, they will need division more frequently since they can quickly become root-bound in a pot. For additional ideas, explore these summer bulbs for containers.
Managing Pests and Performance
When you separate your cannas, you are giving them a fresh start, which often makes them more resistant to problems. However, it is always good to keep an eye out for a few common issues.
If you notice holes in the leaves or "rolled" leaves that won't open, you might have canna leaf rollers (caterpillars). Since you have divided your plants and given them more space, it is easier to spot these pests early. Simply removing the affected leaves is often enough to manage the problem in a home garden.
If your divided cannas are slow to bloom, it is usually a matter of heat and light. Cannas are tropical plants that love the heat. If you have a cool, cloudy summer, they might take a bit longer to start flowering. Be patient; once the temperature stays consistently high, they will catch up quickly.
Realistic Expectations for the First Year
It is important to remember that gardening is a partnership with nature. Weather, soil quality, and local microclimates all play a role in how your plants perform.
When you plant a smaller division, the plant might be slightly shorter in its first year than it was the year before. This is normal. The rhizome is busy building a new root system. By the second year, the plant will have fully established itself and will likely reach its maximum height and flower capacity.
Also, keep in mind that the number of "eyes" matters. A division with three eyes will almost always produce a bushier, more impressive plant in year one than a division with only one eye. If you want an instant impact, keep your divisions on the larger side.
What to do next:
- Keep a garden journal to note which varieties you divided and where you planted them.
- Monitor the soil moisture during the first month of growth.
- Wait for the first flower spike to appear—usually about 60 to 90 days after planting.
The Joy of Shared Gardening
One of the most rewarding aspects of separating canna bulbs is the opportunity to share them. Because cannas multiply so quickly, most gardeners eventually find they have more than they can use.
Passing along a few "Tropicanna Black" or "City of Portland" rhizomes to a neighbor or a friend is a wonderful way to spread the love of gardening. When you give someone a division, you are giving them a piece of your own garden that will continue to grow and bloom for years to come.
Cannas are the perfect "beginner" plant to share because they are so hardy and provide such immediate gratification. A single rhizome in a brown paper bag is a promise of a tropical summer, and that is a gift anyone can appreciate.
Summary of the Division Process
Separating cannas doesn't have to be a chore. It is a simple, rhythmic part of the gardening seasons. By following a few basic steps, you ensure that your garden remains vibrant and that your plants stay at their peak performance.
- Lift the clump carefully with a garden fork after the foliage is cut back.
- Clean the rhizomes with water to see the eyes and joints clearly.
- Cut the mass into 3-to-5-inch sections, ensuring each has 2 or 3 healthy eyes.
- Discard any old, woody, or soft material that won't grow well.
- Cure the pieces by letting them air-dry before storing or replanting.
With these steps, you will turn a single crowded clump into a whole new generation of tropical beauty.
Conclusion
Separating canna bulbs is one of the most effective ways to keep your summer garden looking its best. It’s a simple act of maintenance that rewards you with more flowers, healthier foliage, and extra plants to share with friends. By taking the time to divide your rhizomes every few years, you are investing in the long-term beauty of your landscape.
At Longfield Gardens, we want to help you feel confident in every gardening task. Whether you are lifting cannas for the first time or you’ve been doing it for decades, remember that these plants are incredibly resilient and eager to grow. The effort you put in now will pay off with a stunning, tropical display all summer long.
- Always look for at least two "eyes" per division for the best results.
- Let the cut surfaces dry out for a few hours to prevent rot.
- Plant in full sun and keep the soil moist for maximum bloom power.
Separating your cannas is like giving your garden a fresh start every spring—it’s an easy win that guarantees a more beautiful yard.
Ready to start your next garden project? Explore the Canna Assorted Collection and other summer-blooming favorites to find the perfect addition to your home.
FAQ
When is the best time of year to separate my canna bulbs?
The most common times are in the fall after the first frost or in the early spring before planting. If you live in a cold climate, dividing them in the fall when you lift them for storage is often the most convenient choice.
How many "eyes" should I leave on each canna division?
We recommend leaving at least two or three healthy eyes per section. While a single eye can technically grow into a plant, having multiple eyes ensures a much fuller and more vigorous plant during the first growing season.
Can I separate cannas while they are still in full bloom?
It is best to avoid dividing cannas while they are actively flowering. Moving and cutting the plant during its peak growth stage causes unnecessary stress and will likely end the blooming season prematurely. Wait until the foliage begins to yellow in the fall or divide them in early spring while they are still dormant.
Do I need to use a special tool to cut the canna rhizomes?
A sharp, clean garden knife or even a serrated kitchen knife works perfectly. The most important thing is that the blade is sharp so it makes a clean cut rather than crushing the fleshy tissue, and that it is clean to avoid spreading any soil-borne diseases.
