Table of Contents
- Introduction
- The Physical Characteristics of a Canna Rhizome
- Identifying the "Eyes" and Growing Points
- Understanding Rhizomes vs. True Bulbs
- Healthy vs. Unhealthy: What to Look For
- Can You Tell the Variety by the Rhizome?
- How the Look Changes When Digging Them Up
- Preparing the Rhizome for Planting
- The Life Cycle: From Root to Sprout
- Practical Tips for Handling Canna Rhizomes
- Summary of Appearance
- FAQ
Introduction
There is nothing quite like the excitement of unpacking a fresh shipment of summer bulbs. When you are planning for a garden filled with towering stems and vibrant, tropical flowers, the anticipation of that first sprout is a highlight of the spring season. Among the most impressive of these summer favorites are cannas. At Longfield Gardens, we want to help you feel confident the moment you open your package, ensuring you know exactly what to look for to get your garden off to a great start.
While many people call them "bulbs," cannas actually grow from a specialized root structure. Understanding the unique appearance of these roots helps you plant them correctly and identify them if you find them tucked away in your garden or storage. For a broader overview, see our All About Cannas guide. This guide will walk you through the physical characteristics of canna rhizomes, how to tell a healthy one from a weak one, and how their appearance changes throughout the growing season. By the end, you will be able to identify these tropical powerhouses by sight and feel.
The Physical Characteristics of a Canna Rhizome
When you first see a canna "bulb," you might notice that it looks very different from a rounded tulip or onion-shaped lily bulb. Technically, cannas grow from rhizomes. A rhizome is a fleshy, underground stem that grows horizontally. If you have ever bought fresh ginger root at the grocery store, you already have a great mental image of what to expect.
Shape and Structure
Canna rhizomes are irregular and lumpy. They are not uniform in size or shape, which is part of their charm. You will see thick, cylindrical segments that look like "fingers" or "elbows" branching off from a main central point. These segments are where the plant stores the energy it needs to produce those massive leaves and bright flowers.
Because they grow horizontally, the rhizome is usually longer than it is wide. A typical specimen is between three and six inches long, though they can be larger depending on the variety and the age of the plant. The surface is often bumpy, with distinct ridges or rings along the length of each segment.
Color and Texture
The exterior of a healthy canna rhizome is usually a creamy white, light tan, or soft pinkish-brown color. The skin is thin and may have a slightly papery or scaly texture in some spots. If you were to nick the surface, the inside is typically white and starchy, much like a potato.
You might also see small, hair-like roots trailing off the bottom or sides. These are the secondary roots that help the plant anchor itself and absorb water once it is in the soil. It is perfectly normal for these roots to look a bit dry or brittle when the rhizome is dormant; the plant will grow fresh, vigorous roots once it senses warmth and moisture.
Weight and Feel
One of the best ways to identify a high-quality canna is by how it feels in your hand. A healthy rhizome should feel heavy for its size. This weight indicates that it is full of moisture and stored nutrients. It should feel firm to the touch, similar to a fresh carrot. If it feels hollow, light, or "squishy," it may have lost too much moisture during storage.
Key Takeaway: Canna rhizomes look like thick, fleshy ginger roots with an irregular, segmented shape and a firm, heavy feel.
Identifying the "Eyes" and Growing Points
The most important visual feature to look for on a canna rhizome is the "eye." Just like the eyes on a potato, these are the points where the new growth will emerge. Being able to spot these eyes is the key to knowing which way to plant the rhizome.
What do eyes look like?
The eyes appear as small, pointed bumps or buds on the surface of the rhizome. They are often a lighter color than the rest of the skin—sometimes a pale pink, white, or light green. Depending on how close the plant is to "waking up," these eyes might be barely visible as tiny nubs, or they might have already started to elongate into a pointed sprout.
Number of eyes
When we select rhizomes for our customers, we look for specimens that have multiple eyes. A rhizome with three to five eyes is ideal because it ensures the plant will produce several stalks, leading to a fuller, more impressive display in your garden. If you are looking for a step-by-step planting refresher, see our How to Plant Canna Lily Bulbs guide. If you see a rhizome that looks like a single, smooth tube with no bumps, it may take longer to sprout.
Signs of active growth
In late spring, as temperatures rise, the eyes will begin to swell. You might see a "nose" or a spear-shaped tip starting to push out. This is a great sign! It means the plant is ready to grow. If these sprouts are long and pale (which can happen if they are kept in a dark box for too long), don't worry. Once they are planted and reach the sunlight, they will turn green and begin to develop leaves.
Understanding Rhizomes vs. True Bulbs
It is common to use the word "bulb" as a catch-all term for any plant part that is buried in the spring for summer color. However, knowing the difference between a rhizome and a true bulb helps you understand how the plant grows and moves through the soil.
A true bulb, like a tulip or an onion, is a complete underground storage house made of fleshy layers (modified leaves). It has a distinct "up" and "down" with a flat basal plate at the bottom and a pointed top.
Cannas are different because their rhizomes are actually stems that grow sideways under the soil. This horizontal growth is why cannas tend to spread out and form a thick clump over time. While a tulip stays in one spot and produces a daughter bulb next to it, a canna rhizome inches forward through the dirt, sending up new stalks from various points along its length.
This structural difference also affects how you handle them. You can't really "peel" a canna like you might the outer skin of a lily. Instead, you treat it like a sturdy root.
Healthy vs. Unhealthy: What to Look For
Before you head out to the garden, it is a good idea to give your rhizomes a quick inspection. Most variations in appearance are perfectly normal, but there are a few things that indicate a plant is in prime condition.
The signs of a healthy rhizome
- Firmness: It should not give when you press on it.
- Color: The skin should be mostly uniform without large, dark, sunken spots.
- Plumpness: It should look "full" rather than shriveled or wrinkled.
- Presence of eyes: At least one or two visible buds or bumps.
What is normal (don't worry about these)
Sometimes a rhizome will arrive with a bit of surface mold or a "dusty" appearance. This is common during shipping and storage. As long as the rhizome underneath is firm, this surface dust won't affect the plant's health. If you do run into damage or labeling issues, our 100% guarantee page explains how we make it right. You may also see "scars" where the rhizome was separated from a larger clump. These look like dry, corky patches and are a normal part of the division process.
Simple Steps for Evaluating Your Plants
- Press gently: Check for firm flesh.
- Check the weight: Heavy rhizomes are hydrated rhizomes.
- Look for buds: Find the points where growth will start.
- Smell it: A healthy rhizome smells like clean earth; it should never have a sour or unpleasant odor.
Can You Tell the Variety by the Rhizome?
Many gardeners wonder if they can tell which color the flowers will be just by looking at the "bulb." For the most part, canna rhizomes look very similar across different varieties. Whether it is a giant six-foot variety or a compact three-foot dwarf, the underground structure remains a tan, fleshy root.
However, there are sometimes subtle clues. Varieties with dark foliage—like the deep burgundy leaves of 'Black Knight' or the bronze tones of 'Wyoming'—may have rhizomes with a slightly darker, pinkish-purple tint to the skin or the eyes. Green-leaved varieties, like The President or 'Lucifer', tend to have paler, cream-colored rhizomes.
Since it is difficult to be 100% sure once they are out of the package, we always recommend labeling your plants immediately. Using a simple garden stake or even writing the name on the rhizome with a soft garden marker before planting can save you a lot of guesswork later in the season.
How the Look Changes When Digging Them Up
If you live in a region where the ground freezes (USDA zones 7 and colder), you will likely dig up your cannas in the fall to save them for next year. When you lift them out of the ground in October or November, they will look very different than they did in May.
The "Clump" Effect
During the summer, that single three-inch rhizome you planted will have grown and expanded significantly. When you dig it up, you will find a large, heavy mass of interconnected rhizomes. It might be the size of a dinner plate or even a basketball! This is the plant's way of multiplying.
Identifying the Old vs. New
The "mother" rhizome (the one you originally planted) will often look darker and more wrinkled. Attached to it will be several "daughter" rhizomes—these are the fresh, plump, light-colored roots that grew during the current season. These new sections are the ones that will provide the best flowers next year.
Cleaning for Storage
When you first pull them up, they will be covered in soil and a dense mat of roots. To see the rhizomes clearly, you can gently shake off the loose dirt. You will see the stems of the plant (which you should cut back to about 2-3 inches) emerging directly from the top of the rhizomes. These stem "stumps" are another great visual indicator of which side is up.
Next Steps for Success:
- After digging, let the clump dry in a shaded, frost-free area for a day or two.
- Brush away excess soil so you can see the individual sections.
- Look for firm, plump sections with visible eyes to save for next spring.
Preparing the Rhizome for Planting
Before the rhizome goes into the ground, there are a few visual cues that can help you prepare it for the best possible growth.
Dividing Large Rhizomes
If you have a very large rhizome with many branches, you can actually break or cut it into smaller pieces. Each piece just needs at least one or two healthy eyes to grow into a full plant. When you do this, look for the "joints" where the rhizome naturally narrows. You can snap them by hand or use a clean knife. The "wound" where you made the cut will look wet at first; let it sit in the air for a few hours to "callus" over (dry out and form a skin) before planting to prevent moisture issues.
Identifying "Up" vs. "Down"
This is the most common question we hear! Because cannas are horizontal rhizomes, they aren't as picky as true bulbs. If you see a clear sprout or a stem stump from last year, that side goes up. If the rhizome is just a lumpy log, plant it horizontally. The plant is very smart—the eyes will grow toward the warmth of the sun, and the roots will grow toward the moisture of the soil regardless of the exact orientation.
The Life Cycle: From Root to Sprout
Watching a canna transition from a dormant root to a tropical giant is a rewarding experience. In the first few weeks after planting, the look of the rhizome changes as it "wakes up."
- Hydration: The rhizome absorbs water from the soil and becomes even firmer.
- Rooting: Tiny white thread-like roots begin to zip out from the sides and bottom of the rhizome.
- Sprouting: The eyes swell and turn into "spikes." These spikes are often a pale green or red color and look like little spears pushing through the soil surface.
- Unfurling: Once the spike is a few inches above ground, it will begin to unfurl. Canna leaves grow in a spiral pattern, wrapped tightly around the center stem.
For the tallest options, browse our Tall Cannas collection. Knowing what these stages look like helps you monitor your garden's progress. If you don't see anything above ground for two or three weeks, don't worry! Cannas love heat. If the soil is still cool, the rhizome will simply wait for the "all-clear" signal from the sun before it starts its big show.
Practical Tips for Handling Canna Rhizomes
Handling these plants is very straightforward, but a few simple habits can ensure they stay in great shape from the moment they arrive at your door until they are safely in the ground.
Unpacking
When your order from us arrives, open the box immediately. Canna rhizomes need to breathe. They are usually shipped in peat moss or paper to manage moisture. For shipping details, see our Shipping Information page. If you aren't ready to plant them yet, keep them in a cool, dark, and dry place (like a basement or garage). They should stay in their packing material to prevent them from drying out completely.
Soaking
Some gardeners like to soak their canna rhizomes in a bucket of lukewarm water for a few hours before planting. Visually, you will see the rhizome plump up slightly. This isn't strictly necessary if your soil is moist, but it can give the plant a little "jump start," especially if the rhizome looks a bit dry after its winter nap.
Space to Grow
Because you now know that cannas grow from horizontal rhizomes that spread, you can visualize why they need space. Planting them too close together can lead to a crowded look where the plants compete for sunlight. For smaller spaces, browse Short Cannas. Give them about 1 to 2 feet of space so the rhizomes have plenty of room to "travel" and expand under the soil.
Summary of Appearance
To wrap up, identifying a canna "bulb" is all about looking for that characteristic ginger-root shape. It is a sturdy, fleshy underground stem that is built for endurance and high-impact growth.
- Shape: Lumpy, segmented, horizontal, and irregular.
- Color: Creamy white to tan, sometimes with pinkish buds.
- Key Features: Look for the "eyes" (buds) and the "stumps" of old stems.
- Texture: Firm and heavy, not soft or hollow.
At Longfield Gardens, we take pride in providing large, healthy rhizomes that are ready to burst into life. Whether you are planting them in large patio containers or using them as a dramatic backdrop in your perennial borders, knowing what they look like—and what they need—is the first step toward a successful growing season. If you want a middle-ground option, see Medium Cannas.
"A healthy canna rhizome is the foundation of a tropical garden. When you start with a firm, multi-eyed root, you are setting the stage for a summer filled with height, texture, and brilliant color."
FAQ
Is it a bulb or a rhizome?
While often marketed as "summer bulbs," cannas grow from rhizomes, which are thick, fleshy underground stems. Unlike true bulbs that have layers like an onion, rhizomes grow horizontally and store energy in their dense, starchy centers.
Which way is up when planting a canna rhizome?
Look for any pointed nubs (eyes) or the remains of last year's stalks (stumps); these should point upward. If the rhizome is a smooth, horizontal segment with no obvious growth points, simply lay it flat in the planting hole, and it will find its way up.
What should I do if my canna rhizome feels soft?
A healthy rhizome should be firm, similar to a fresh potato. If it feels slightly soft but not mushy, you can try soaking it in water for a few hours to rehydrate it. However, if it is very squishy or has a sour smell, it may not be viable and should not be planted.
Why does my rhizome look like a piece of ginger?
Cannas and ginger are actually distant relatives in the plant world! They share the same "rhizomatous" growth habit, which results in that iconic segmented, knobby appearance designed to store water and nutrients for the plant.