Table of Contents
- Introduction
- Understanding Canna Rhizomes
- The Ideal Depth for Canna Bulbs
- How to Plant Canna Bulbs in the Garden
- Planting Cannas in Containers
- The Importance of Soil Temperature
- Watering Correctly for Strong Growth
- Nourishing Your Cannas for Better Blooms
- Maintenance and Summer Care
- Lifting and Storing for Winter
- Common Mistakes to Avoid
- Why Quality Matters
- Conclusion
- FAQ
Introduction
Adding a splash of the tropics to your backyard is one of the most rewarding ways to celebrate the arrival of summer. With their oversized, paddle-shaped leaves and brilliant, orchid-like blooms, cannas bring an immediate sense of lushness and energy to any landscape. Whether you are planting them in a sweeping garden border or as a dramatic centerpiece in a patio container, these fast-growing plants are remarkably easy to enjoy when you get the basics right. If you’re shopping for a taller, statement-making look, browse our Tall Cannas collection.
At Longfield Gardens, we want to help you feel confident as you transform your outdoor space into a colorful retreat. One of the most common questions we hear from home gardeners is how deep to plant these unique rhizomes. While cannas are resilient and eager to grow, setting them at the correct depth ensures they have the physical support they need to stand tall and the protection they require to establish strong roots.
This guide will focus on the practical steps of planting cannas, with a specific focus on finding that "sweet spot" for planting depth. We will also cover site selection, soil preparation, and simple care tips to keep your plants thriving from the first sprout to the final frost. For a broader overview of canna care, see All About Cannas.
Getting your cannas off to a great start begins with understanding exactly how to place them in the soil for maximum success.
Understanding Canna Rhizomes
Before we dig into the planting process, it helps to know exactly what you are holding. Although most people 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 closely at a canna rhizome, you will see small bumps or points called "eyes." These eyes are where the new stems and leaves will emerge. For a fuller look at the plant itself, see the Medium Cannas collection.
Rhizomes are naturally sturdy, but they do have a preferred orientation. When you look at the rhizome, you will usually notice a flatter side and a side with more bumps or perhaps the remnants of last year’s stems. While cannas are clever enough to eventually find the light even if planted upside down, placing them correctly gives them a significant head start.
Finding the "up" side is simple once you know what to look for. The eyes or sprouts should point toward the sky. If you cannot tell which side is which, do not worry. You can simply lay the rhizome on its side. In the natural world, rhizomes grow horizontally, and the plant will easily navigate its way to the surface from this position.
The Ideal Depth for Canna Bulbs
The most important rule for planting cannas is to bury the rhizome at a depth where it is protected but can still easily send up new growth. For most garden situations, you should bury canna rhizomes so they are covered by 2 to 3 inches of soil. This means the top of the rhizome should be at least two inches below the surface of the earth.
This specific depth provides several benefits for the plant. First, it offers a layer of insulation against fluctuating spring temperatures. Even after the danger of frost has passed, the air temperature can change quickly, but soil deep down stays more consistent. Second, 2 to 3 inches of soil provides enough weight and structure to anchor the plant. Since cannas can grow quite tall—sometimes reaching five feet or more—a solid foundation is essential to prevent them from tipping over in a summer breeze.
If you plant them too shallowly, the rhizomes may dry out or the heavy stems might pull the plant out of the ground as they grow. If you plant them much deeper than 4 or 5 inches, the shoots may struggle to reach the surface, leading to a delay in blooming. Sticking to the 2- to 3-inch rule ensures a perfect balance between protection and speed of growth.
Key Takeaway: For most varieties, aim for a depth where 2 to 3 inches of soil covers the top of the rhizome. This provides the best anchor for tall stems while allowing sprouts to reach the sun quickly.
How to Plant Canna Bulbs in the Garden
Once you have identified the right depth, the actual planting process is quick and enjoyable. Planting in the garden allows you to create large massings of color or architectural focal points among your other perennials.
Step 1: Select a Sunny Spot
Cannas are sun-worshippers. To get the most vibrant flower colors and the largest leaves, choose a location that receives at least 6 to 8 hours of direct sunlight each day. While they can grow in partial shade, they will likely produce fewer flowers and may become a bit "leggy" as they stretch toward the light.
Step 2: Prepare the Soil
Cannas are "heavy feeders," meaning they appreciate soil that is rich in nutrients. Before planting, we recommend loosening the soil to a depth of about 8 to 12 inches. This makes it easier for the new roots to spread out and establish themselves. If your soil is very sandy or heavy clay, mixing in a few inches of compost or well-rotted manure can improve the texture and provide a natural boost of energy.
Step 3: Dig and Place
Dig a hole or a trench that is about 4 inches deep. This allows you to place the rhizome in the hole and still have plenty of room to cover it with the recommended 2 to 3 inches of soil. Space your cannas about 12 to 18 inches apart. This might seem like a lot of space when they are just small rhizomes, but they grow rapidly and will quickly fill in the gaps with lush foliage.
Step 4: Cover and Firm
After placing the rhizome horizontally with the eyes facing up (or on its side), backfill the hole with the soil you removed. Gently press down on the soil with your hands to remove any large air pockets. You do not need to pack it down hard; just a light firming is enough to ensure the soil is in contact with the rhizome.
Step 5: Initial Watering
Water the area thoroughly right after planting. This helps settle the soil around the rhizome and signals to the plant that it is time to wake up. After this initial watering, you can wait until you see the first green shoots before you begin a regular watering schedule.
Planting Cannas in Containers
If you have limited garden space or want to decorate a porch or patio, cannas are excellent candidates for container life. Many dwarf and mid-sized varieties are specifically bred to look fantastic in pots, and you can compare options in the Canna Assorted Mix - Bulk Offer.
When planting in containers, the depth remains similar to garden planting, but there are a few extra considerations. We recommend using a pot that is at least 12 to 18 inches in diameter. This gives the rhizome enough room to grow without becoming root-bound too quickly. Use a high-quality potting mix rather than garden soil, as potting mix is designed to drain well and stay light and fluffy in a container environment.
In a pot, you can still follow the 2- to 3-inch depth rule. However, make sure to leave an inch or two of space between the top of the soil and the rim of the pot. This "headspace" makes it much easier to water the plant without the water and soil spilling over the edge. Because containers dry out faster than the ground, you may find that your potted cannas need water more frequently once they start growing vigorously. For more container guidance, see How to Keep Container Plants Looking Their Best.
What to do next:
- Pick a pot with drainage holes to prevent soggy roots.
- Fill the pot halfway with potting mix.
- Place the rhizome and cover with 3 inches of mix.
- Leave a 2-inch gap at the top for easy watering.
- Move the pot to a sunny location.
The Importance of Soil Temperature
While depth is a major factor in success, timing is just as critical. Many gardeners are eager to get their bulbs in the ground as soon as the first warm day of spring arrives. However, cannas are tropical plants that originated in warm climates. They do not like cold soil. If you want to get a jump on the season, see Starting Canna Lily Bulbs Indoors.
We recommend waiting to plant your cannas until the soil temperature is consistently at least 60°F. In many parts of the US, this happens around the same time you would plant tomatoes or peppers. If the soil is too cold and wet, the rhizome may sit dormant for a long time or, in extreme cases, begin to rot before it has a chance to grow.
A simple way to check is to use a soil thermometer, or simply wait until the nighttime air temperatures are reliably above 50°F. If you live in a region with a short growing season and want to get a jump on the summer, you can start your cannas indoors in pots about 4 to 6 weeks before the last frost date. This gives them a head start so they are already growing by the time the garden soil is warm enough for transplanting.
Watering Correctly for Strong Growth
Once your cannas have been planted at the correct depth and have started to peek through the soil, their water needs will increase. Cannas are naturally thirsty plants. In their native habitats, they often grow near the edges of ponds or in damp, marshy areas.
The rule for watering cannas is to keep the soil consistently moist but not swampy. During the heat of the summer, especially if you have sandy soil, this might mean watering a few times a week. If you are growing them in containers, you may even need to water every day during a heatwave.
To check if your cannas need water, stick your finger an inch into the soil. If it feels dry, it is time for a deep soak. Deep watering encourages the roots to grow further down into the earth, which makes the plant more stable and drought-tolerant in the long run. Adding a thin layer of mulch, such as shredded bark or clean straw, around the base of the plants can help hold moisture in the soil and keep the roots cool.
Nourishing Your Cannas for Better Blooms
Because cannas grow so much foliage and produce such large flowers in a single season, they require a fair amount of energy. Planting them at the right depth gives them the foundation, but fertilizing gives them the fuel.
When you first plant your rhizomes, you can mix a bit of balanced, slow-release fertilizer into the soil. As the season progresses and the plants begin to grow rapidly in mid-summer, you can apply a liquid fertilizer every few weeks. Look for a fertilizer that is balanced (such as a 10-10-10 formula) or one that is slightly higher in phosphorus to encourage more blooms.
If your soil is already very rich with compost, you might find that your cannas grow perfectly well without much extra help. However, if you notice the leaves looking a bit pale or the flowering seems sparse, a quick feeding is often all they need to get back on track. Always follow the instructions on the fertilizer label to ensure you are providing the right amount for your specific garden size.
Maintenance and Summer Care
One of the best things about cannas is how low-maintenance they are once established. Beyond regular watering and feeding, there are only a few simple tasks to keep them looking their best.
Deadheading
As the flowers begin to fade, you can remove them to keep the plant looking tidy. This process is called deadheading. Canna stems often produce multiple flower clusters. When one flower fades, snip it off just above the next bud. Once the entire flower stalk has finished blooming and no more buds are visible, you can cut that specific stalk back to where it meets the large leaves. This encourages the plant to put its energy into new growth and more flowers rather than producing seeds.
Monitoring for Pests
Cannas are generally very healthy, but they can occasionally attract "leaf rollers." These are small caterpillars that stitch the edges of the leaves together to create a little tunnel. If you see leaves that are rolled up and won't unfurl, you can usually simply unroll them by hand and remove the caterpillar. For a bold foliage option, see Canna Tall Tropicanna.
Wind Protection
Because cannas have such large leaves, they can act like sails in a strong wind. If you live in a particularly breezy area, planting them near a fence or a wall can provide some helpful shelter. This prevents the leaves from becoming tattered or the tall stems from leaning.
Lifting and Storing for Winter
In warmer parts of the country (USDA zones 7 through 10), cannas can often stay in the ground all year long. In these areas, you can simply cut the foliage back to the ground after it turns brown in the fall and add a layer of mulch for protection. For a quick reference, use the Hardiness Zone Map.
However, if you live in a colder zone (zone 6 or lower), the winter frost will freeze the ground and damage the rhizomes. Since we want you to enjoy your cannas year after year, we recommend "lifting" them in the autumn. For step-by-step overwintering help, see How to Store Canna Bulbs for Winter.
The process is simple:
- Wait for the first frost to blacken the foliage.
- Cut the stems down to about 4 inches above the soil.
- Use a garden fork or shovel to gently lift the rhizome clump out of the ground.
- Shake off the excess soil and let the rhizomes dry in a cool, shaded area for a few days.
- Store them in a box filled with peat moss, perlite, or wood shavings in a cool, dark place (like a basement or crawlspace) where temperatures stay between 40°F and 50°F.
In the spring, you can divide the large clumps into smaller pieces, ensuring each piece has at least one or two "eyes," and start the planting process all over again.
Common Mistakes to Avoid
While cannas are very forgiving, avoiding a few common pitfalls will help you get the best results. The most frequent mistake is planting too early. It is tempting to get into the garden on the first sunny day of April, but waiting for that 60°F soil temperature is the single best thing you can do for your cannas.
Another common issue is planting the rhizomes vertically like a carrot. While the plant will usually figure it out, it takes much longer for the sprouts to reach the surface. Always aim for a horizontal placement.
Finally, do not be afraid of the water. Unlike some bulbs that prefer to stay dry, cannas are quite happy with extra moisture. If you treat them more like a tropical water plant than a desert cactus, they will reward you with massive growth and stunning color.
Simple Gardening Rules for Cannas:
- Right Place: Full sun and rich, moist soil.
- Timing: Wait for 60°F soil; don't rush the cold.
- Depth: 2 to 3 inches of soil coverage is the goal.
- Water: Keep it consistent; deep soaks are better than light mists.
Why Quality Matters
When you start with high-quality rhizomes, the entire gardening process feels easier and more successful. At Longfield Gardens, we work with experienced growers to ensure that the rhizomes we ship to you are healthy, firm, and ready to grow. If you want to compare another standout, Canna Tall Tropicanna Black offers a darker foliage contrast.
We maintain a trial garden where we evaluate different varieties for their color, height, and performance in real-world conditions. A bright, striped option like Canna Tall Pretoria is a good example of the kinds of bold forms that can anchor a summer display.
By choosing premium plants, you are giving yourself the best chance of seeing those impressive 10-to-12-week bloom timelines. When your shipment arrives, it is a good idea to open the box immediately and check your plants. They should feel heavy for their size and firm to the touch. If you aren't ready to plant right away, keep them in a cool, dry place until the weather is just right. For shipping timing and delivery details, see Shipping Information.
We stand behind the quality of everything we ship with a 100% guarantee. Our goal is to make sure your first experience with cannas—and every experience after that—is one of pure gardening joy. You can learn more about the company behind that promise on our About Us page.
Conclusion
Planting canna lilies is a straightforward way to add high-impact beauty to your home landscape. By focusing on the correct depth—burying your rhizomes under 2 to 3 inches of soil—and waiting for the soil to warm up in the spring, you set the stage for a spectacular summer display. These plants are built for speed and drama, and they ask for very little in return for their stunning foliage and blooms.
As you plan your garden this year, consider where a touch of the tropics might brighten your view. Whether it’s a row of tall, striped foliage along a fence or a few pots of a variegated selection on your deck, these plants are sure to become a highlight of your outdoor space. If you prefer a variegated look, Canna Tall Stuttgart is another striking option.
- Select a sunny spot with at least 6 hours of light.
- Wait for the soil to reach 60°F before planting outdoors.
- Bury the rhizomes 2 to 3 inches deep and space them 12 to 18 inches apart.
- Keep the soil consistently moist throughout the growing season.
At Longfield Gardens, we believe that gardening should be an achievable and rewarding experience for everyone. By getting the basics of depth and timing right, you are well on your way to a more beautiful and vibrant garden.
FAQ
Which way should the "eyes" on a canna rhizome point when planting?
The "eyes," which are the small bumps or sprouts on the rhizome, should point upward toward the sky. This allows the new stems to grow straight to the surface. If you cannot identify the eyes, simply lay the rhizome on its side, and the plant will naturally find its way up.
Can I plant canna bulbs deeper than 3 inches?
While you can plant them slightly deeper, we recommend staying between 2 and 3 inches of soil coverage. If they are buried too deep, it will take much longer for the sprouts to emerge, which can delay your blooming season. A depth of 2 to 3 inches provides the best balance of stability and quick growth.
What happens if I plant my cannas before the soil is 60 degrees?
If the soil is too cold, the rhizome will remain dormant and won't begin to grow. In cold, wet spring soil, there is a higher risk of the rhizome rotting before it has a chance to sprout. It is always better to wait for the ground to warm up or to start your cannas indoors in a controlled environment.
Do canna lilies need to be planted at a different depth in pots?
The planting depth in containers is generally the same as in the ground, with about 2 to 3 inches of potting mix covering the rhizome. The main difference is ensuring you leave enough room at the top of the pot for watering. Make sure the container is large enough to accommodate the fast-growing roots and provide stability for the tall stems.