Table of Contents
- Introduction
- Understanding Canna Rhizomes
- When Is the Best Time to Separate Canna Bulbs?
- Tools You Will Need
- How Do You Separate Canna Bulbs: A Step-by-Step Guide
- Dividing Potted Cannas
- Aftercare and Replanting Your Separated Cannas
- Storing Divided Cannas for the Winter
- Why Some Cannas Don't Need Frequent Separation
- Realistic Expectations for Your Divided Cannas
- Common Canna Varieties to Multiply
- Simple Troubleshooting After Separation
- Conclusion
- FAQ
Introduction
One of the greatest joys in the garden is watching the lush, tropical foliage of a canna lily unfurl in the warmth of summer. These plants bring an undeniable energy to the landscape, with their bold leaves and vibrant, torch-like blooms. At Longfield Gardens, we believe that gardening should be a rewarding experience that keeps on giving, and cannas are the perfect example of this. Because they grow from vigorous underground structures, a single plant can quickly become a spectacular clump that provides beauty for years to come.
Separating these plants is one of the most satisfying tasks a gardener can undertake because it is essentially a way to get more plants for free. Whether you want to expand your garden beds, fill more containers, or share a favorite variety with a neighbor, learning how to divide cannas is a simple skill that yields big results. This guide is designed for home gardeners who want to understand the best techniques for separating canna rhizomes to ensure healthy growth and maximum flower production.
By mastering a few basic steps, you can keep your cannas vigorous and enjoy a garden filled with tropical color every season. Separating canna rhizomes is an easy, effective way to multiply your plant collection while maintaining the health and vitality of your original garden display.
Understanding Canna Rhizomes
To successfully separate cannas, it helps to understand what you are working with. While many gardeners refer to them as "bulbs," cannas actually grow from rhizomes. A rhizome is a thickened, horizontal underground stem that stores energy for the plant. If you look at one, it might remind you of a piece of ginger root.
These rhizomes are the engine of the plant. They store the nutrients and moisture needed to push out those massive leaves and tall flower stalks. Over a single growing season, a healthy canna rhizome will expand and grow "offsets" or new sections. If left alone for several years, these clumps can become quite large and crowded.
Crowded rhizomes often compete for nutrients and space, which can lead to smaller leaves and fewer flowers. This is why separation is so beneficial. When you divide a large clump into smaller pieces, you give each new plant the room it needs to thrive. Each section you cut away has the potential to become a full-sized, blooming plant by the end of the summer.
When Is the Best Time to Separate Canna Bulbs?
Timing is one of the most important factors when it comes to garden success. For cannas, there are two primary windows of opportunity for separation: spring and fall. The choice usually depends on your climate and how you manage your plants over the winter.
Spring Separation (The Ideal Choice)
In most regions, spring is the best time to separate canna rhizomes. This is typically done just as the plants are waking up from their winter dormancy but before they have put significant energy into tall new growth. As the soil warms and you see small "eyes" or buds beginning to swell on the rhizomes, the plant is ready to be handled.
Dividing in the spring allows the new sections to go straight into the ground or a pot, where they can immediately begin establishing a root system. This timing minimizes the amount of time the cut surfaces are exposed to the air, which reduces the risk of the rhizome drying out. For a fuller planting and storage guide, see All About Cannas.
Fall Separation (For Easy Storage)
If you live in a region where cannas are not hardy (Zones 7 and colder), check the USDA Hardiness Zone Map. Many gardeners find it convenient to separate the clumps at this time.
Separating in the fall makes the rhizomes easier to clean and takes up less storage space. If you choose this route, it is important to let the cut pieces "cure" or dry for a few days before packing them away. This allows the cut surface to form a protective callous, which helps prevent rot during the winter months.
Key Takeaway: While spring is the most common time for division, separating in the fall is a great space-saving technique for gardeners who must store their cannas indoors for the winter.
Tools You Will Need
One of the reasons separating cannas is so accessible is that it requires very few specialized tools. You likely already have everything you need in your garden shed.
- A Sturdy Garden Spade or Fork: You will need this to lift the large clumps out of the ground without damaging the rhizomes.
- A Sharp Knife: A dedicated garden knife, a large serrated kitchen knife, or even a clean box cutter will work. The key is that the blade must be sharp to ensure clean cuts.
- A Garden Hose: This is essential for washing away soil so you can clearly see where to make your cuts.
- Gloves: Canna rhizomes are sturdy, but the surrounding soil can be tough on your hands.
- Rubbing Alcohol or a 10% Bleach Solution: Use this to clean your knife between different plants to prevent the spread of any potential soil-borne diseases.
How Do You Separate Canna Bulbs: A Step-by-Step Guide
The process of separating cannas is straightforward and quite forgiving. Follow these steps to ensure your new plants get the best possible start.
Step 1: Lifting the Clump
If your cannas are in the ground, start by cutting back the foliage to about 3 or 4 inches above the soil line. Use your garden spade to dig a wide circle around the base of the plant. Cannas have a spreading growth habit, so the rhizomes may be further from the center than you expect.
Gently pry the clump upward. It is better to lift a large amount of soil along with the plant than to risk slicing through a healthy rhizome with your shovel. Once the clump is out of the ground, shake off as much loose soil as possible.
Step 2: Cleaning and Inspection
This is the most important step for a beginner. Use a garden hose to wash the remaining soil off the rhizomes. You want to see the "eyes" clearly. The eyes are the small, rounded bumps or points on the rhizome where new stems will grow. They often look like the eyes on a potato.
Inspect the clump for any soft, mushy, or shriveled areas. These should be trimmed away and discarded, as they are signs of age or rot. You only want to keep the firm, healthy-looking sections.
Step 3: Identifying Your Cut Points
Look for natural "joints" in the rhizome structure. A large clump is usually made up of several interconnected rhizomes. Your goal is to cut the clump into sections that each have at least two to three healthy eyes.
While a single eye can technically grow into a plant, a piece with two or three eyes has more stored energy. This extra energy helps the plant grow faster and produce flowers sooner in the season.
Step 4: Making the Cuts
Use your sharp, clean knife to slice through the rhizome. Try to make the cut as clean as possible rather than "sawing" through it. A clean cut heals faster than a jagged one.
As you work, remember to dip your knife in your cleaning solution if you move from one large parent clump to another. This simple step is a great way to maintain a healthy garden.
Step 5: Curing the Rhizomes
If you are separating in the spring and planting immediately, you can put the pieces right into the soil. However, many gardeners prefer to let the cut pieces sit in a dry, shaded spot for 24 hours. This allows the "wound" to dry out and form a callous. This callous acts as a barrier against soil bacteria and moisture, which helps prevent the rhizome from rotting after it is planted.
What to Do Next:
- Lift the clump carefully to avoid bruising.
- Wash away all soil so the "eyes" are visible.
- Cut sections so each has 2-3 healthy eyes.
- Allow cut surfaces to dry and callous before planting or storing.
Dividing Potted Cannas
Many gardeners grow cannas in large containers to add a tropical flair to patios and decks. Because containers offer limited space, cannas in pots usually need to be divided every year or two. For more container-growing tips, see Short Cannas.
When a canna becomes "root-bound" in a pot, you may notice that water runs straight through without soaking in, or the plant may stop blooming as vigorously. To separate these, simply tip the pot over and slide the root ball out. You may need to run a knife around the inside edge of the pot to loosen it.
Once the plant is out, follow the same steps for cleaning and cutting. Potted cannas often have very dense root systems, so don't be afraid to use a bit of muscle to separate the rhizomes. After dividing, replant one or two healthy sections back into the pot with fresh potting soil and move the remaining pieces to other containers or into the garden. For more container-growing tips, see How to Grow Summer Bulbs in Containers.
Aftercare and Replanting Your Separated Cannas
Once you have your newly separated rhizomes, the next step is getting them back into the soil so they can start growing. Proper planting ensures that your hard work in separating them pays off with a beautiful display.
Choosing the Right Spot
Cannas are sun-lovers. To get the best leaf color and the most flowers, choose a spot that receives at least six to eight hours of direct sunlight every day. They also appreciate "drainage," which is simply the soil's ability to let water flow through it freely. While cannas like moisture, they do not like to sit in soggy, stagnant mud, which can cause the rhizomes to rot.
Planting Depth and Spacing
A common question for beginners is how deep to plant the rhizomes. A good rule of thumb is to plant them about 3 to 4 inches deep. If you are planting in the garden, space the rhizomes about 12 to 18 inches apart. This might look like a lot of empty space at first, but cannas grow quickly and will fill that gap in just a few months. For a step-by-step visual guide, see How to Plant Canna Lily Bulbs.
When placing the rhizome in the hole, lay it horizontally (flat) with the eyes facing upward. If you can't tell which way is up, don't worry—the plant will figure it out and find the light, though it might take a few extra days to break through the soil.
Watering and Initial Care
After planting, water the area well to settle the soil around the rhizomes. From that point on, keep the soil consistently moist but not saturated. As the weather warms up and the leaves begin to appear, you can increase the frequency of watering. Cannas are thirsty plants, especially during the heat of mid-summer.
Storing Divided Cannas for the Winter
If you chose to separate your cannas in the fall, you now have a collection of clean, calloused rhizomes ready for winter storage. Storing them correctly is the key to ensuring they are ready to grow again next spring.
Place the separated rhizomes in a sturdy box or plastic bin. Many gardeners like to layer them with slightly damp peat moss, vermiculite, or wood shavings. This provides just enough moisture to keep the rhizomes from shriveling up but not so much that they start to rot.
Store the container in a cool, dark place where the temperature stays between 40°F and 50°F. A basement, crawlspace, or insulated garage is usually perfect. Avoid areas that might freeze, as freezing temperatures will turn the rhizomes into mush. Check on them once or twice during the winter; if they look shriveled, a very light misting of water on the packing material is all they need.
Why Some Cannas Don't Need Frequent Separation
While most cannas benefit from being divided every two or three years, the necessity depends on the variety and your growing conditions. At Longfield Gardens, we offer a wide range of cannas, from dwarf varieties that stay compact to towering giants that can reach six feet or more.
Compact varieties, such as those often used in small pots, may need more frequent division because they run out of "real estate" in the container very quickly. In contrast, large-scale varieties like 'Wyoming' or tall cannas have more room to spread out if they are planted in a large garden bed.
You can tell your cannas are ready for separation when:
- The clump has become so dense that the center of the plant isn't producing as many flowers.
- The rhizomes are visible on the surface of the soil.
- The plant has outgrown its allotted space in the garden.
- You simply want to create more plants for another area of your yard.
Realistic Expectations for Your Divided Cannas
When you separate a canna rhizome, it is important to remember that the plant is essentially "starting over" in its new location. While cannas are fast growers, it may take a few weeks for the new section to establish its roots before you see much growth above ground.
The weather plays a major role in how fast your separated cannas will grow. Cannas thrive on heat. If the spring is unusually cool or wet, they may stay dormant longer than usual. This is perfectly normal. Once the night-time temperatures consistently stay above 60°F, you will see a dramatic increase in growth.
Also, the size of the rhizome piece you plant will influence the initial size of the plant. A very small piece with only one eye will still grow into a beautiful plant, but it may take a little longer to reach its full height and produce its first flower spike compared to a larger section.
Common Canna Varieties to Multiply
Because cannas are so easy to separate, you can quickly build a massive collection of your favorite varieties. Here are a few popular types that respond beautifully to division:
- Canna 'Pretoria' (Bengal Tiger): Known for its striking yellow and green striped leaves and bright orange flowers. Dividing this variety allows you to repeat that stunning foliage pattern throughout your garden.
- Canna 'Wyoming': This variety features dark, bronze-toned leaves and brilliant orange blossoms. It is a vigorous grower that produces plenty of rhizomes for separation.
- Canna 'The President': A classic variety with large, clear red flowers and deep green foliage. It is very reliable and a great choice for beginners practicing their division skills.
- Canna 'Phaison' (Tropicanna): This variety is a showstopper with multi-colored leaves featuring stripes of pink, red, and gold. Because it is so highly sought after, separating your own rhizomes is a cost-effective way to get more of this premium plant.
Simple Troubleshooting After Separation
If your newly separated cannas aren't performing as expected, the solution is usually simple. Most issues relate to the environment rather than the act of separation itself.
Slow Growth: This is usually due to cool soil. If you planted early in the spring, the rhizomes might just be waiting for more warmth. You can help by placing black mulch or landscape fabric over the soil to help it absorb more heat from the sun.
No Flowers: If your foliage looks great but you aren't seeing blooms, the plant may not be getting enough light. Cannas need full sun to produce flowers. Another common cause is a lack of water; cannas need consistent moisture to fuel the production of flower spikes.
Yellowing Leaves: While some cannas have naturally yellow patterns, overall yellowing of the leaf can indicate a lack of nutrients. A balanced, water-soluble fertilizer applied every few weeks during the growing season can give the plants the boost they need.
Key Takeaway: Success with separated cannas comes down to "the big three": heat, sun, and water. If you provide those, your new plants will almost always thrive.
Conclusion
Separating canna rhizomes is one of the most rewarding and straightforward tasks in the garden. It is a simple process that not only keeps your plants healthy and vigorous but also allows you to expand your tropical landscape at no extra cost. By following the basic steps of lifting, cleaning, and cutting with care, you can ensure that each new section of your canna clump has a bright future ahead.
At Longfield Gardens, we want every gardener to feel confident in their ability to grow and multiply these spectacular plants. Remember that gardening is a journey of observation and learning. Each time you divide a plant, you become more in tune with its growth cycle and its needs. Whether you are filling a new garden bed with the bronze leaves of 'Wyoming' or potting up 'Pretoria' to give to a friend, the results of your work will bring color and joy to the summer months.
- Separate cannas in spring for the easiest transition to growth.
- Ensure each divided section has 2–3 healthy "eyes."
- Provide plenty of sun, heat, and water for the best results.
- Let cut surfaces callous before planting to prevent rot.
The secret to a lush, tropical-looking garden is often just a matter of a sharp knife and a little bit of time spent dividing your favorite plants.
For your next gardening project, consider trying a new color or leaf pattern from our Fresh Ideas for Growing Cannas collection of premium canna rhizomes. With just one or two seasons of growth, you’ll have plenty of plants to separate and share!
At Longfield Gardens, our 100% guarantee backs up every order.
FAQ
How many "eyes" does a canna rhizome need to grow?
While a canna rhizome can technically grow from a single eye, we recommend ensuring each piece has at least two or three eyes. These eyes are the points where new stems emerge, and having multiple eyes provides the plant with more stored energy to establish itself quickly. Pieces with more eyes generally produce a larger, more robust plant in their first season after separation.
Can I separate cannas while they are in full bloom?
It is best to avoid separating cannas while they are actively blooming. During the flowering stage, the plant is directing all its energy into the blooms and seed production, and the stress of being dug up and cut can cause the plant to wilt or lose its flowers. For the best results and the healthiest plants, wait until the plant is dormant in late fall or just waking up in early spring.
Do I need to use a special sealant on the cut parts of the rhizome?
You do not need any special waxes or sealants for canna rhizomes. The most effective way to protect the cut is to let it "cure" or dry out in a shaded, well-ventilated area for about 24 hours. This allows the plant to form its own natural callous, which is the best defense against soil-borne bacteria and rot.
What should I do if my canna rhizomes feel soft after I dig them up?
If a rhizome feels soft or mushy, it is likely suffering from rot caused by overwatering or poor drainage. When you are separating your clumps, simply cut away and discard any soft or shriveled sections. Only keep the parts that feel firm and heavy for their size, as these are the healthy sections that will produce the best growth next season.