Table of Contents
- Introduction
- Understanding the "Bulb": It’s Actually a Rhizome
- Anatomy of a High-Quality Canna Rhizome
- Why Cannas Belong in Your Garden
- Choosing the Right Canna for Your Space
- Site Selection: Right Plant, Right Place
- Timing: When to Plant Canna Bulbs
- How to Plant Canna Rhizomes
- Container Gardening with Cannas
- Ongoing Summer Care
- End-of-Season Care and Winter Storage
- Conclusion
- FAQ
Introduction
Nothing transforms a backyard into a tropical paradise quite like the bold, architectural presence of cannas. With their oversized, banana-like leaves and vibrant, jewel-toned flowers, these plants bring an immediate sense of energy and exotic flair to any landscape. Whether you are looking to create a lush privacy screen, add a pop of color to a sunny border, or design a dramatic container display, cannas are the reliable workhorses that make it happen with minimal effort.
At Longfield Gardens, we know that the secret to a stunning summer garden often starts with these impressive "bulbs." For a broader look at these plants, see our All About Cannas guide. While they are famous for their height and showy blooms, there is much more to these plants than meets the eye. They are resilient, fast-growing, and surprisingly easy to care for, making them a favorite for both beginning gardeners and seasoned pros alike.
In this guide, we will answer the question of what are canna bulbs, exploring their unique botany, how they grow, and why they are such a valuable addition to your outdoor space. We will also cover the basics of choosing the right varieties and preparing your garden for a successful growing season. Understanding the nature of these tropical beauties is the first step toward a more vibrant and beautiful garden.
Understanding the "Bulb": It’s Actually a Rhizome
When people ask what are canna bulbs, they are usually referring to the dormant root-like structures we plant in the spring. However, if we want to be botanically accurate, cannas do not grow from true bulbs like tulips or daffodils. Instead, they grow from something called a rhizome.
A rhizome is a thickened, fleshy underground stem that grows horizontally just beneath the soil surface. Unlike a true bulb, which is a complete, self-contained miniature plant surrounded by fleshy scales (like an onion), a rhizome is a storage organ for the plant’s energy. It holds onto starches and proteins that the plant uses to fuel its rapid growth once the weather warms up.
Because cannas are tropical plants, their rhizomes are designed to survive periods of dormancy in warm climates. They act as a battery, storing everything the plant needs to push out those massive leaves and tall flower stalks in a single season. While the term "canna bulb" is widely used in the gardening industry for simplicity, knowing that you are working with a rhizome helps you understand how to plant and care for them more effectively.
The Role of "Eyes" in Growth
If you look closely at a canna rhizome, you will notice several small, bumpy protrusions or points. These are often called "eyes," much like the eyes on a potato. Each eye represents a potential new growth point. When the soil reaches the right temperature, these eyes sprout, sending shoots upward to become stems and leaves, while roots grow downward from the bottom of the rhizome to anchor the plant and drink in moisture.
Storage and Resilience
The fleshy nature of the rhizome is what makes cannas so resilient. Because they store so much water and energy, they can handle the heat of mid-summer better than many other perennials. This storage capacity also allows them to grow at an incredible rate—some varieties can reach heights of six to eight feet in just a few months.
Anatomy of a High-Quality Canna Rhizome
When you are ready to start your garden, the quality of the "bulb" you begin with determines the vigor of your plants. Not all rhizomes are created equal, and knowing what to look for will help you ensure a season full of lush foliage and bright blooms.
We prioritize quality because we want your gardening experience to be rewarding from day one. Our 100% Quality Guarantee backs every order. A healthy canna rhizome should feel firm and heavy for its size. If a rhizome feels light, hollow, or shriveled, it may have dried out too much during storage and might struggle to sprout.
Size and Eye Count
One of the easiest ways to judge a canna rhizome is by its size and the number of visible eyes. At our facility, we look for rhizomes that are plump and well-developed. Generally, a larger rhizome with three to five eyes will produce a more robust plant than a smaller one with only one or two eyes. More eyes mean more stems, which leads to a fuller, more impressive display in your garden or containers.
Texture and Color
A healthy rhizome usually has a tan or creamy-white exterior, sometimes with a few papery scales. The flesh inside should be firm. While it is normal for the outside to be a bit dusty or have a few dry roots attached, the main body of the rhizome should be solid. Avoid any that feel mushy or show signs of significant mold, as these are indicators of poor health.
Key Takeaway: Start with the best materials. A firm, heavy rhizome with multiple "eyes" is the foundation for a tall, healthy plant that will bloom all summer long.
Why Cannas Belong in Your Garden
Cannas offer a unique combination of benefits that few other plants can match. They are versatile, tough, and provide a vertical element that adds professional-looking structure to your landscape. Here are a few reasons why we love including them in our garden plans.
Dramatic Foliage
While the flowers are certainly beautiful, many gardeners grow cannas primarily for their foliage. The leaves are massive, often reaching two feet in length, and they come in a stunning array of colors. You can find varieties with deep emerald green leaves, rich burgundy or bronze tones, and even variegated patterns with stripes of yellow, white, and lime green. This bold texture provides a perfect backdrop for smaller, finer-textured plants.
Pollinator Appeal
Canna flowers are rich in nectar and have a shape that is perfectly suited for hummingbirds. If you want to attract these flying jewels to your yard, planting a row of red or orange cannas is one of the most effective ways to do it. They also attract bees and butterflies, contributing to a healthy, active backyard ecosystem.
Moisture Tolerance
Most garden bulbs require perfect drainage to avoid rotting, but cannas are surprisingly flexible. While they grow best in well-drained, rich soil, they are one of the few decorative plants that can tolerate "wet feet." They are excellent choices for rain gardens or for planting near the edge of a pond where the soil stays consistently damp.
Fast Privacy and Screening
Because cannas grow so quickly, they are an ideal solution for temporary privacy. A single row of tall cannas can create a lush, living screen that hides a fence, a utility box, or a neighbor’s view in just a few months. Since they grow from the ground up every year, you don’t have to worry about the long-term maintenance of a woody hedge.
Choosing the Right Canna for Your Space
Not all cannas are towering giants. Over the years, plant breeders have developed a wide range of sizes and colors to fit almost any garden situation. When you are deciding which ones to buy, consider both the ultimate height of the plant and the color of the foliage.
Tall Cannas
These are the classic tall varieties that usually reach between 4 and 6 feet, though some can soar to 8 feet under ideal conditions. They are best for the back of a flower bed or for creating screens.
Short Cannas
These compact versions typically stay between 2 and 3 feet tall. They are perfect for the front or middle of a border and are the best choice for medium-sized containers. They provide all the tropical beauty of their larger cousins without taking up as much vertical space.
Foliage and Flower Combinations
We recommend thinking about your garden’s color palette when selecting cannas.
- Green Foliage: Varieties with bright green leaves, like The President (red flowers) or 'Richard Wallace' (yellow flowers), offer a clean, classic tropical look.
- Dark Foliage: Varieties with bronze or burgundy leaves, such as Australia or 'Wyoming,' create a moody, sophisticated contrast. The dark leaves make the bright orange or red flowers pop even more.
- Variegated Foliage: If you want a real showstopper, look for varieties like Pretoria (also known as 'Bengal Tiger') or 'Phasion' (often called Tropicanna). Their leaves feature bold stripes that make the plant look beautiful even when it isn't in bloom.
For an even bolder striped look, Phasion (Tropicanna) is another standout.
Site Selection: Right Plant, Right Place
Cannas are not particularly fussy, but they do have a few "must-haves" if you want them to reach their full potential. Getting the location right is the most important step in your planting process.
Sun is Key
Cannas are sun-worshippers. To produce those big leaves and continuous blooms, they need plenty of energy from the sun. We recommend a spot that receives at least 6 to 8 hours of direct sunlight every day. In cooler northern climates, full sun is non-negotiable. In very hot southern climates, they can handle a bit of afternoon shade, but too much shade will result in "leggy" plants that don't bloom well.
Soil and Drainage
As mentioned, cannas are quite adaptable, but they perform best in soil that is rich in organic matter. If your soil is heavy clay or very sandy, mixing in some compost or well-rotted manure before planting will give them the nutrients they need to grow fast. While they can handle damp soil, they still appreciate a spot where water doesn't stand for days on end after a heavy rain.
Wind Protection
Because canna leaves are so large, they can sometimes act like sails in high winds. If you live in a very windy area, try to plant your cannas near a wall, fence, or other windbreak. This prevents the leaves from shredding, keeping the plant looking tidy and lush all season long.
Timing: When to Plant Canna Bulbs
Timing is everything when it comes to tropical plants. Because cannas are sensitive to the cold, planting them too early can stunt their growth or cause the rhizomes to rot in cold, wet soil.
Wait for the Warmth
The simplest rule for cannas is to wait until the danger of frost has completely passed. However, soil temperature is actually a better guide than the calendar. We recommend waiting until the soil has warmed up to at least 65°F. In most parts of the country, this happens about two to three weeks after the last spring frost. If you're buying ahead of time, our Shipping Information page can help you plan delivery by zone.
Starting Early Indoors
If you live in a region with a short growing season, you can get a head start by "waking up" your canna rhizomes indoors. About four to six weeks before the last frost date, plant the rhizomes in pots with potting soil and place them in a warm, sunny window or under grow lights. By the time the weather is warm enough to move them outside, you will already have established plants ready to take off. See our Starting Canna Lily Bulbs Indoors guide for a simple step-by-step version.
What to do next:
- Check your local frost dates to determine your safe planting window.
- Purchase a simple soil thermometer to check for that 65°F sweet spot.
- Prepare your pots if you plan to start your rhizomes indoors.
How to Plant Canna Rhizomes
Planting cannas is a straightforward process. Because they grow horizontally, the way you position the rhizome in the ground matters.
Preparation
Loosen the soil in your planting area to a depth of about 8 to 10 inches. This makes it easier for the new roots to spread out and establish themselves. If you are planting in a bed, you can mix in a little balanced, slow-release fertilizer at this stage.
Depth and Spacing
- Depth: Plant the rhizomes about 2 to 3 inches deep. You want enough soil on top to keep them hydrated and protected, but not so much that the young shoots struggle to reach the surface.
- Orientation: Lay the rhizome horizontally in the hole. Look for the "eyes" or any small sprouts and point them upward. If you can’t tell which side is up, don't worry—the plant is smart enough to find the light and will send its shoots toward the surface regardless.
- Spacing: Give them room to breathe. Tall varieties should be spaced 18 to 24 inches apart. Smaller dwarf varieties can be planted 12 inches apart. This ensures good airflow between the plants, which helps prevent disease. For more spacing guidance, see our How Many Canna Bulbs to Plant Together for a Lush Garden guide.
Watering After Planting
Once the rhizomes are in the ground and covered with soil, give them a good soak. This settles the soil around the rhizome and eliminates air pockets. After this initial watering, be careful not to overwater until you see the first green shoots poking through the ground. Once they start growing, you can increase the frequency of watering.
For a closer look at planting depth, see our How to Deep to Plant a Canna Bulb guide.
Container Gardening with Cannas
If you don't have a large garden plot, or if you want to dress up your patio, cannas are excellent candidates for container life. Their upright growth makes them the perfect "thriller" in a thriller-filler-spiller pot arrangement.
Choosing the Right Pot
Because cannas grow large and have vigorous root systems, they need plenty of space. For a single standard-sized canna, we recommend a pot that is at least 15 to 18 inches in diameter. If you are using dwarf varieties, you can fit them into slightly smaller containers or plant two or three together in a larger whiskey-barrel-sized planter.
Potting Mix and Care
Always use a high-quality potting soil rather than garden soil, as garden soil is too heavy for containers and won't drain properly. Because containers dry out faster than the ground, you will need to water your potted cannas frequently—sometimes every day during the heat of the summer.
Stability
Tall cannas in pots can become top-heavy. To prevent the wind from tipping them over, choose heavy pots made of ceramic or terra cotta, or place a few heavy stones at the bottom of a plastic pot before adding soil.
Ongoing Summer Care
Once your cannas are established, they are relatively low-maintenance, but a little extra attention will keep them blooming until the first frost.
Water Correctly, Not Constantly
Cannas are thirsty plants. They prefer soil that is consistently moist. During the peak of summer, they may need a deep watering twice a week (or more for containers). The best approach is to water deeply, allowing the moisture to reach the root zone, rather than giving them frequent light sprinkles.
Fertilizing for Blooms
Because cannas grow so fast and produce so much foliage, they are "heavy feeders." They appreciate a monthly dose of a balanced liquid fertilizer or a granular fertilizer formulated for flowering plants. This provides the phosphorus needed to keep the flower spikes coming.
Deadheading
As the individual flowers on a spike fade, you can pinch them off to keep the plant looking tidy. Once an entire flower stalk has finished blooming, cut it back to the next set of leaves. This encourages the plant to produce a new flower stalk rather than putting energy into making seeds.
End-of-Season Care and Winter Storage
One of the most important things to know when asking what are canna bulbs is how they handle the winter. Your approach will depend entirely on where you live.
In Warm Climates (Zones 8–10)
In these regions, cannas are perennials that can stay in the ground year-round. Once the foliage begins to yellow or die back in late fall, simply cut the stems down to about 2 or 3 inches above the soil. You can add a layer of mulch over the top for extra protection, and they will sprout again when the weather warms in the spring.
In Cooler Climates (Zones 3–7)
In these zones, the ground freezes deep enough to kill the rhizomes. You have two choices: treat them as annuals and buy fresh rhizomes each spring, or "lift" and store them for the winter.
How to Lift and Store Cannas:
- Wait for Frost: Wait until the first light frost kills the foliage. This tells the plant to move its remaining energy down into the rhizome.
- Cut Back: Cut the stalks down to about 4 inches.
- Dig Carefully: Use a garden fork or shovel to gently lift the clump of rhizomes out of the ground. Be careful not to bruise or cut the fleshy centers.
- Dry: Shake off the excess soil and let the rhizomes dry in a shaded, frost-free area (like a garage) for a few days.
- Pack: Place the rhizomes in a cardboard box or a breathable bag filled with slightly damp peat moss, vermiculite, or wood shavings.
- Store: Keep the box in a cool, dark, and dry place (around 45–50°F). A basement or crawlspace is usually ideal. Check them once or twice during the winter; if they look shriveled, mist the packing material with a little water.
Key Takeaway: Winter storage is an easy way to save your favorite varieties year after year. Just remember to keep them cool and dry so they don't rot or sprout too early.
Conclusion
Cannas are truly the ultimate "bang for your buck" plant. For the price of a few rhizomes and a little bit of sunshine, you can create a towering, tropical oasis that lasts from early summer through the first frost of autumn. Whether you are drawn to their massive, colorful leaves or their bright, hummingbird-attracting flowers, there is a variety that fits perfectly into your garden plan.
At Longfield Gardens, we are dedicated to helping you find success with every bulb and rhizome you plant. By following the simple steps of choosing quality rhizomes, waiting for the warm soil, and providing plenty of water and sun, you can enjoy a spectacular display of tropical beauty right in your own backyard.
- Choose the right size: Use tall varieties for screens and dwarf varieties for pots.
- Prioritize sun: Give them at least 6 hours of direct light for the best blooms.
- Keep them hydrated: Cannas love moisture, especially in the heat of summer.
- Save for next year: If you live in a cold climate, lift the rhizomes in the fall to enjoy them again next season.
Ready to add some tropical flair to your landscape? Start planning your garden today and experience the rewarding, fast-paced growth of these incredible plants.
FAQ
Are canna lilies actual lilies?
No, cannas are not true lilies. While they are often called "canna lilies" due to their showy flowers, they are actually more closely related to gingers and bananas. Unlike true lilies which grow from a layered bulb, cannas grow from a thick underground stem called a rhizome.
Why aren't my cannas blooming?
The most common reason for a lack of blooms is a lack of sunlight. Cannas need at least 6 to 8 hours of direct sun to produce flowers. Other factors include planting in soil that is too cold, which stunts growth, or a lack of nutrients; as heavy feeders, they often need regular fertilizer to fuel flower production.
Can I grow cannas in pots?
Absolutely! Cannas are excellent container plants. Dwarf varieties are particularly well-suited for pots, but even tall varieties can thrive in large, heavy containers (at least 15–18 inches wide) as long as they receive plenty of water and regular fertilizer throughout the growing season.
Do I have to dig up my canna bulbs every year?
This depends on your USDA hardiness zone. Check our Hardiness Zone Map to confirm your zone. If you live in Zone 8 or warmer, you can usually leave your cannas in the ground year-round with a layer of mulch for protection. If you live in Zone 7 or colder, the rhizomes will freeze and rot if left in the ground, so you must lift and store them indoors for the winter.