Table of Contents
- Introduction
- Why Spacing Is the Key to Canna Success
- How Far Apart to Plant Standard Canna Lily Bulbs
- Spacing for Dwarf and Compact Cannas
- Planting Cannas in Containers
- The Relationship Between Depth and Spacing
- Site Selection: Matching Spacing to Environment
- Creating a Tropical Screen or Privacy Wall
- How to Calculate How Many Rhizomes You Need
- Practical Tips for the Planting Process
- Caring for Your Spaced Cannas
- Managing Expectations: Growth and Weather
- Spacing and Winter Storage
- Conclusion
- FAQ
Introduction
Imagine stepping into your backyard and being greeted by a wall of lush, vibrant foliage and brilliant, tropical blooms that make every day feel like a vacation. Canna lilies are the ultimate garden showstoppers, offering bold textures and colors that can transform a standard flower bed into a stunning landscape. At Longfield Gardens, we know that the secret to achieving that professional, high-impact look starts with a few simple planting steps.
Whether you are looking to create a living privacy screen or a colorful focal point in a patio pot, getting the spacing right is the most important part of the process. For more container inspiration, see our Best Summer Bulbs for Containers. Proper spacing ensures each plant has enough room to reach its full potential without competing for the resources it needs to thrive. In this guide, we will walk you through exactly how far apart to plant canna lily bulbs—technically called rhizomes—to ensure your garden is healthy, beautiful, and full of life all season long.
By understanding the needs of different varieties and the specific conditions of your yard, you can plant with confidence and enjoy a spectacular summer display.
Why Spacing Is the Key to Canna Success
When you first hold a canna rhizome in your hand, it might look small and unassuming. However, these plants are famous for their rapid growth and "big eater" reputation. In a single season, a standard canna can grow from a quiet underground stem to a towering six-foot-tall botanical giant. Because they grow so quickly and produce such massive leaves, the distance between each plant matters significantly.
Giving your cannas the right amount of elbow room serves several purposes. First, it ensures that every leaf gets the sunlight it needs. Cannas are sun-worshippers, and if they are packed too tightly, the larger leaves will shade out the smaller ones, leading to leggy growth and fewer flowers. Second, proper spacing allows for healthy air circulation. While cannas love moisture, stagnant air between dense foliage can sometimes lead to fungal issues.
Finally, cannas are heavy feeders that require plenty of nutrients and water from the soil. If they are crowded, they have to compete for these resources. By following our spacing recommendations, you are giving each plant a dedicated "pantry" of soil to pull from, which results in more vibrant colors and taller stems.
Key Takeaway: Correct spacing prevents competition for light and nutrients, leading to a more robust and floriferous garden display.
How Far Apart to Plant Standard Canna Lily Bulbs
For most common canna varieties, which typically reach heights of 4 to 6 feet, the ideal spacing is 18 to 24 inches apart. This measurement is taken from the center of one planting hole to the center of the next.
If you are planting a long row to create a border or a temporary summer hedge, staying closer to the 18-inch mark will help the foliage knit together faster, creating a seamless wall of green or bronze. If you are planting them in a mixed garden bed where you want to see the individual shape of each plant, or if you are interplanting them with other perennials, 24 inches is the better choice.
We recommend staggering your rows if you are planting a large area. Instead of a grid pattern, plant them in a "V" or zigzag shape. This fills in the gaps more effectively and makes the display look much fuller and more natural from every angle.
Considerations for Tall Varieties
Some heritage varieties or specific tall cultivars can reach 8 feet or more in ideal conditions. For these "horticultural titans," lean toward the 24-inch spacing. Their root systems are more expansive, and their larger leaf canopy requires more room to unfurl without being shredded by the wind against neighboring stems.
Spacing for Drifts and Masses
If you have a large landscape and want to create a "drift"—a natural-looking mass of color—space the rhizomes roughly 20 inches apart in a curved, kidney-shaped area. This creates a high-density color punch that looks intentional and lush rather than cluttered.
Spacing for Dwarf and Compact Cannas
Not every garden has room for a six-foot plant, which is why dwarf cannas are so popular for smaller suburban yards and narrow garden borders. Varieties like 'Salmon Pink' or 'Orange Punch' typically top out at 2 to 4 feet tall. Because these plants are smaller in stature and have a more compact growth habit, you can plant them closer together.
For dwarf or compact cannas, space the rhizomes 12 to 15 inches apart. This closer spacing allows these shorter plants to form a dense, colorful carpet of foliage that is perfect for the front of a flower bed.
Even though they are smaller, dwarf cannas still produce multiple "eyes" or growing points on each rhizome. They will spread horizontally over the summer, so giving them at least a foot of space ensures they won't become root-bound or overcrowded by mid-August when they are at their peak.
- Standard Cannas: 18–24 inches apart.
- Dwarf Cannas: 12–15 inches apart.
- Hedge/Screen Planting: 18 inches apart in staggered rows.
Planting Cannas in Containers
Growing canna lilies in pots is a fantastic way to add a tropical feel to a deck, patio, or entryway. However, the rules for spacing change slightly when you are working within the confines of a container.
For the best results, use a large pot. A container with an 18-inch diameter is the minimum size we recommend for a single standard canna rhizome. If you have a very large planter—around 24 to 30 inches in diameter—you can plant two or three rhizomes together.
When planting multiple rhizomes in a pot, space them about 6 to 8 inches apart. While this is much closer than the spacing used in the ground, the limited space in a container actually helps keep the plants' height somewhat manageable while focusing their energy on lush foliage and flowers. Just keep in mind that container-grown cannas will need much more frequent watering and fertilizing than those in the ground because they are sharing a smaller volume of soil. For more inspiration, read Fresh Ideas for Growing Cannas.
Key Takeaway: Use one rhizome per 18-inch pot, or space them 6–8 inches apart in very large planters to ensure enough room for root development.
The Relationship Between Depth and Spacing
While spacing determines how the plants grow outward, planting depth determines how well they grow upward. Getting the depth right is just as important as the distance between the bulbs.
In most garden soils, canna rhizomes should be planted 3 to 4 inches deep. If you have very sandy soil that dries out quickly, you can go slightly deeper—up to 5 inches—to help keep the rhizome cool and moist. In heavy clay soil, stay at the 3-inch mark to ensure the sprout can reach the surface easily.
When you place the rhizome in the hole, look for the "eyes" or the small, pointy bumps. These are the growth buds. Place the rhizome horizontally with the eyes facing up toward the sky. If you can’t tell which way is up, don’t worry; the plant is smart enough to find the light, but pointing the eyes upward gives it a helpful head start.
Steps for a Successful Planting
- Loosen the Soil: Dig down about 10 to 12 inches to loosen the earth before planting. This makes it easier for the new roots to spread.
- Measure the Distance: Use a ruler or a pre-marked garden stake to ensure your 18-to-24-inch spacing is consistent.
- Set the Rhizome: Place the bulb at the correct depth and cover with soil.
- Tamp and Water: Press the soil down gently to remove air pockets and water thoroughly to settle the soil around the rhizome.
Site Selection: Matching Spacing to Environment
The "Right Plant, Right Place" rule is a core principle at Longfield Gardens. The environment where you plant your cannas can actually influence how you should space them.
Sun and Spacing
If your planting site receives the recommended 6 to 8 hours of direct sunlight, you can stick to the standard 18-to-24-inch spacing. However, if your spot is a bit more "part-sun" (around 4 to 6 hours), the plants may grow slightly taller and "leggier" as they reach for the light. In these lower-light conditions, it is better to space them 24 inches apart to ensure as much light as possible reaches the lower leaves.
Soil and Moisture
Cannas thrive in rich, moist soil. If you are planting in an area that stays naturally damp—such as near a pond or a low spot in the yard—the plants will likely grow larger and spread more aggressively. In these high-moisture areas, give them the full 24 inches of space. If your soil is leaner or drier, they may stay a bit smaller, and 18 inches will be sufficient to create a full look.
Creating a Tropical Screen or Privacy Wall
One of the most popular uses for canna lilies is creating a seasonal privacy screen. Because they grow so tall so quickly, they are perfect for blocking a view of a neighbor's yard or hiding an unsightly fence during the summer months.
To create a dense screen, follow these steps:
- Create Two Rows: Instead of one single line, plant two parallel rows about 18 inches apart.
- Stagger the Placement: Place the plants in the second row so they sit in the "gaps" of the first row (the zigzag pattern).
- Use 18-inch Spacing: Within the rows, space the rhizomes 18 inches apart.
This staggered, double-row method creates a thick wall of foliage that provides excellent privacy by mid-summer. Varieties with dark or variegated foliage, like 'Tropical Bronze' or Stuttgart, are particularly effective for this because their leaves are very broad and opaque.
Key Takeaway: For a privacy screen, use a staggered double-row pattern with 18-inch spacing to create a dense, interlocking wall of foliage.
How to Calculate How Many Rhizomes You Need
Before you start digging, it helps to know how many rhizomes to order. Using the 18-to-24-inch rule, you can easily calculate the right number for your space.
- For a 10-foot Border: If you plant one every 24 inches, you will need 5 rhizomes. If you want a denser look at 18 inches, you will need 7.
- For a 5'x5' Square Garden: Using 24-inch spacing, you would plant a 3x3 grid, requiring 9 rhizomes.
- For Large Drifts: A good rule of thumb is to plan for approximately 3 standard cannas for every 10 square feet of garden space.
Remember that cannas are perennials in warm climates (Zones 8-11). If you need help confirming your zone, check the Hardiness Zone Map. In these areas, they will multiply underground each year. If you live in a warm zone, start with the wider 24-inch spacing, knowing that the clumps will grow and fill the gaps within two or three seasons.
Practical Tips for the Planting Process
Gardening is meant to be a rewarding and enjoyable activity. To make the task of planting multiple canna bulbs easier, we suggest preparing the entire bed at once rather than digging individual holes one by one.
Prepare the Bed
Turn over the soil in your entire planting area and mix in a few inches of compost or well-rotted manure. Cannas are hungry plants, and giving them a nutrient-rich "bed" to start in makes a world of difference. Once the soil is prepped and smooth, you can simply lay the rhizomes out on top of the soil at your desired 18-to-24-inch intervals. This allows you to visualize the final look before you ever put a shovel in the ground.
Digging the Holes
Once you are happy with the layout, move from one rhizome to the next, digging a small hole 4 inches deep, tucking the rhizome in, and covering it back up. This "layout first" method ensures your spacing is perfect and you won't end up with an extra bulb at the end of the row with nowhere to put it.
Watering and Initial Care
After planting, water the area deeply. You want the soil to be moist but not a muddy swamp. It can take two to three weeks for the first sprouts to appear, especially if the soil is still warming up. Be patient—once they start, they grow incredibly fast!
What to Do Next:
- Measure your garden bed to determine the total square footage.
- Choose your favorite varieties based on the height that fits your space.
- Mark your planting spots with a handful of flour or garden stakes.
- Amend the soil with compost to give your bulbs a healthy start.
Caring for Your Spaced Cannas
Once your cannas are in the ground and properly spaced, the hard work is over. However, as the season progresses, a little bit of maintenance will keep them looking their best. For a broader overview, read All About Cannas.
Watering
Because you have given them space, the soil between the plants might dry out faster than if it were shaded by a dense canopy. Check the soil moisture regularly. Cannas love "wet feet" and will be most successful if the soil stays consistently moist. A thin layer of mulch (about 2 inches) can help retain that moisture and keep the roots cool.
Fertilizing
About a month after planting, when the sprouts are several inches tall, you can begin a regular fertilizing schedule. We suggest using a balanced, water-soluble fertilizer every few weeks. Because they are spaced out, you can apply the fertilizer directly around the base of each plant, ensuring the nutrients go exactly where they are needed.
Monitoring Growth
By mid-summer, your cannas should be filling in the 18-to-24-inch gaps. If you notice any leaves that look damaged or shredded by the wind, feel free to prune them off at the base. This keeps the plant looking tidy and encourages new, healthy growth from the center.
Managing Expectations: Growth and Weather
At Longfield Gardens, we want every gardener to have a positive experience. It is important to remember that the exact growth rate and ultimate size of your cannas will depend on your local conditions. In a particularly hot, humid summer with plenty of rain, your cannas may grow larger and faster than they would in a cool, dry year.
If your plants seem a bit slow to start, don't worry. They are simply waiting for the soil to reach a consistently warm temperature (above 60°F). Once the heat of summer arrives, they will quickly make up for lost time. If you gave them the recommended space, they will have all the room they need to explode into growth as soon as the weather hits its stride.
Spacing and Winter Storage
If you live in a cold climate (Zone 7 and lower), you will likely be digging up your canna rhizomes in the fall to store them for the winter. This is actually where your proper spacing pays off again.
When you dig them up after the first frost, you will find that each original rhizome has grown into a much larger clump. If you spaced them 24 inches apart, it will be much easier to dig around the clump without accidentally slicing into the neighboring plant's root system.
When you replant them the following spring, you can divide these large clumps into smaller pieces (each with at least one "eye") and start the spacing process all over again. It is a wonderful way to expand your garden for free!
Conclusion
Planting canna lilies is one of the easiest ways to bring high-impact color and a lush, tropical feel to your home landscape. By simply ensuring that you space your standard cannas 18 to 24 inches apart and your dwarf varieties 12 to 15 inches apart, you set the stage for a healthy, vibrant garden. This "elbow room" is the key to preventing disease, maximizing sunlight, and ensuring every plant has the nutrients it needs to produce those iconic, rainbow-hued blooms.
At Longfield Gardens, we are here to help you grow a garden you love. With a little bit of planning and the right spacing, your canna lilies will thrive from the first sprout of spring to the final frost of autumn.
- Space standard cannas 18–24 inches apart.
- Space dwarf varieties 12–15 inches apart.
- Plant 3–4 inches deep in full sun.
- Keep the soil consistently moist for the best growth.
Getting the spacing right today means enjoying a lush, worry-free tropical paradise all summer long.
FAQ
Can I plant canna lilies closer together for a fuller look?
While you can plant them as close as 12 inches for a very dense, temporary display, we generally recommend 18 to 24 inches for standard types. Planting them too close can lead to competition for sunlight and nutrients, which may result in fewer flowers and smaller leaves. If you want a full look quickly, try staggering two rows in a zigzag pattern instead of crowding them into one line.
How many canna rhizomes can I put in a 12-inch pot?
A 12-inch pot is a bit small for standard canna lilies, which have very aggressive root systems. For a pot that size, we recommend planting only one dwarf cannas. For standard, tall varieties, it is best to use a container that is at least 18 inches in diameter to allow the plant enough room to grow and stay stable in the wind.
How deep should I plant canna lily bulbs?
Canna rhizomes should be planted about 3 to 4 inches deep. This depth provides enough soil cover to keep the rhizome moist and anchored while allowing the young sprout to easily reach the surface. In very hot climates or sandy soil, you can go slightly deeper, up to 5 inches, to protect the bulb from drying out.
When is the best time to plant cannas?
The best time to plant is in the spring once the soil has warmed up to at least 60°F and all danger of frost has passed. In most regions, this is the same time you would plant tomatoes in the garden. If you want a head start, you can plant your rhizomes in pots indoors about four to six weeks before the last frost and then move them outside when the weather is warm. If you're ordering from Longfield Gardens, their Shipping Information page explains zone-based shipping timing.