Table of Contents
- Introduction
- The Ideal Depth for Planting Canna Bulbs
- Understanding Canna Rhizomes
- Step-by-Step Guide to Planting Canna Bulbs
- Spacing and Layout for Maximum Impact
- Timing: The Secret to Fast Growth
- Choosing the Right Location
- Planting Cannas in Containers
- Caring for Your Cannas After Planting
- What to Expect: From Planting to First Bloom
- Winter Care: Storing Your Bulbs for Next Year
- Common Questions About Planting Depth
- Enhancing Your Garden with Canna Varieties
- Summary of Canna Planting Success
- FAQ
Introduction
There is nothing quite like the sight of a canna lily unfurling its massive, paddle-shaped leaves to transform a backyard into a lush tropical oasis. These high-energy plants are favorites for their bold textures and vibrant, iris-like flowers that bloom all summer long. Whether you are looking to create a living privacy screen or want a dramatic focal point in your patio containers, cannas are a rewarding and accessible choice for any gardener.
At Longfield Gardens, we want to help you get the best results from your summer-blooming bulbs. Growing tall cannas is straightforward once you understand their basic needs for warmth, water, and proper placement. This guide focuses on the most critical step of the process: getting the planting depth just right to ensure your plants grow strong and bloom on schedule.
Success with these tropical beauties begins with a few simple steps. For a broader overview, see our All About Cannas guide. By matching the planting depth to the plant's needs and waiting for the right soil temperature, you can enjoy a spectacular display of color until the first frost.
The Ideal Depth for Planting Canna Bulbs
The most common question gardeners ask is exactly how deep to place the rhizomes—which are often called bulbs—in the soil. For the best results, you should plant your canna bulbs about 4 inches deep. This means there should be approximately 3 to 4 inches of soil covering the top of the rhizome once the hole is filled.
Planting at this depth provides the rhizome with enough insulation from fluctuating surface temperatures while keeping it close enough to the surface to feel the sun's warmth. If you plant them too deep, the sprouts may take a long time to reach the surface, which can delay your first flowers. If they are too shallow, the rhizomes might dry out or struggle to anchor the tall, heavy stalks that cannas produce later in the season.
When you are ready to plant, dig a hole that is slightly wider than the rhizome itself. This gives you space to position the bulb comfortably. If you are planting in heavy clay soil, you can plant slightly shallower—around 2 to 3 inches deep—to help the plant emerge faster. In very sandy soil, sticking to the 4-inch depth helps the plant stay hydrated.
Key Takeaway: Plant canna rhizomes 4 inches deep to provide the perfect balance of warmth and stability for the growing stalks.
Understanding Canna Rhizomes
While we often call them bulbs, cannas actually grow from rhizomes. A rhizome is a thick, fleshy underground stem that stores energy for the plant. When you receive your order from us, you will notice these rhizomes look like knobby potatoes with small, pointed bumps.
These bumps are called "eyes." They are the growth points where the new stems and leaves will emerge. Before you put them in the ground, take a look at each piece to identify these eyes. Knowing where the growth starts will help you position the plant correctly in the hole.
Healthy rhizomes should feel firm and heavy for their size. If a rhizome has multiple eyes, that is a sign of a vigorous plant that will produce several stalks of foliage and flowers. Because these are living plants, they are ready to grow as soon as the conditions are right.
Step-by-Step Guide to Planting Canna Bulbs
Planting cannas is a fun weekend project that yields massive results. Follow these simple steps to get your garden started:
- Prepare the site: 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.
- Add organic matter: If your soil is very sandy or heavy clay, mix in a few inches of compost or aged manure. This improves the soil structure and provides a slow-moving source of nutrients.
- Dig the hole: Create a hole about 4 inches deep and wide enough to accommodate the length of the rhizome.
- Position the rhizome: Lay the rhizome horizontally in the hole. Make sure the eyes or any visible sprouts are pointing upward. If you can't tell which way is up, don't worry—the plant will naturally find its way to the surface, but pointing the eyes up gives it a head start.
- Cover and firm: Fill the hole with soil and gently press down with your hands to remove any large air pockets. You don't need to pack it down hard; just a light touch will do.
- Water in: Give the area a good soak immediately after planting to settle the soil around the rhizome.
What to Do Next
- Mark the spot with a garden stake so you don't accidentally dig it up later.
- Wait for the first sprouts to appear before you begin a regular watering schedule.
- Keep the area free of weeds so the young canna doesn't have to compete for nutrients.
Spacing and Layout for Maximum Impact
Cannas are known for their impressive size. Some varieties can grow 6 feet tall or more, while dwarf types stay around 2 or 3 feet. Because they grow so quickly, giving them enough room to breathe is essential for their health.
For standard tall varieties, space the rhizomes 18 to 24 inches apart. This might seem like a lot of space when you are looking at a small bulb, but by mid-summer, those gaps will be filled with lush foliage. If you are planting dwarf varieties, you can bring the spacing in to about 12 inches.
For a fuller look with smaller planting groups, see our Canna Assorted Mix - Bulk Offer. Proper spacing ensures that each plant gets enough sunlight and airflow. Good air circulation is one of the best ways to keep the foliage looking fresh and healthy all season long. If they are crowded, the lower leaves may turn yellow prematurely because they can't get enough light.
"Giving cannas room to grow prevents competition and allows each stalk to reach its full flowering potential."
Timing: The Secret to Fast Growth
One of the most important "rules" for cannas is to wait for the heat. These are tropical plants that love warm soil. If you plant them while the ground is still cold and damp, the rhizomes will simply sit there, and in some cases, they might even rot before they have a chance to grow.
The best time to plant cannas outdoors is when the soil temperature reaches at least 60°F. A good rule of thumb is to plant your cannas at the same time you would put your tomato plants in the garden. For most regions, this is in late spring or early summer, well after the danger of frost has passed. If you want to check your zone before planting, our Hardiness Zone Map is a helpful reference.
If you live in a northern climate with a short growing season, you can give your cannas a head start by planting them in pots indoors. Start them about 4 to 6 weeks before the last expected frost. Place the pots in a warm, sunny window. By the time the weather warms up, you will have established plants ready to be moved into the garden.
Choosing the Right Location
Cannas are not shy about their needs: they want sun and lots of it. To get the brightest flower colors and the most vigorous growth, choose a spot that receives at least 6 to 8 hours of direct sunlight each day.
While they can grow in partial shade, you will notice the difference. In shady spots, the plants tend to become "leggy," meaning the stems grow tall and weak as they stretch toward the light. You will also see fewer flowers in the shade.
For more growing basics, our All About Cannas guide covers planting sites, moisture, and container use. In addition to sun, consider wind protection. Because cannas have such large leaves, they can act like sails in a storm. If you live in a very windy area, planting them against a fence or a wall can help protect the foliage from tearing.
Site Selection Checklist
- Sunlight: 6-8 hours of direct light.
- Soil Drainage: Soil should be moist but never have standing water for more than a few hours.
- Space: Enough vertical room for the plant to reach its full height.
- Protection: Sheltered from strong, breaking winds if possible.
Planting Cannas in Containers
If you have limited garden space or want to decorate a patio, cannas are excellent candidates for container gardening. Because they grow so large, they need a substantial pot to stay balanced and hydrated.
When planting in containers, follow these simple guidelines:
- Pot Size: Choose a container that is at least 12 to 15 inches in diameter for a single rhizome. For a larger display with multiple bulbs, use a half-barrel or a large planter.
- Depth: Stick to the 4-inch depth. Ensure there is enough room at the bottom for root growth and enough room at the top for the soil to cover the bulb.
- Drainage: Make sure your pot has drainage holes. While cannas love water, they do not like to sit in a "swamp" inside a pot where air cannot reach the roots.
- Potting Mix: Use a high-quality potting soil rather than garden soil. Potting soil is lighter and designed to hold moisture while still allowing excess water to drain away.
Containers dry out much faster than the ground, so keep a close eye on the moisture levels. In the heat of mid-summer, potted cannas may need water every day.
Caring for Your Cannas After Planting
Once your cannas are in the ground and the first green shoots appear, their needs are fairly simple. We recommend focusing on two main things: water and food.
Cannas are "hungry" plants. They use a lot of energy to produce those giant leaves and flowers. Applying a balanced, slow-release fertilizer at planting time is a great start. You can follow up with a water-soluble fertilizer every few weeks during the peak of the growing season to keep the blooms coming.
Watering is equally important. Unlike many other bulbs that prefer to dry out between waterings, cannas enjoy consistently moist soil. During dry spells, give them a deep soaking once or twice a week. If the edges of the leaves start to turn brown and crispy, it is often a sign that the plant needs more water.
Quick Care Tips
- Mulch: Apply a 2-inch layer of mulch around the base of the plants to hold in moisture.
- Deadheading: Remove spent flower stalks to encourage the plant to produce new blooms rather than seeds.
- Observation: Check the leaves occasionally for any signs of chewing insects, though cannas are generally very hardy.
What to Expect: From Planting to First Bloom
Gardening is a lesson in patience, but cannas are relatively fast growers once they get started. After planting your rhizomes at the 4-inch depth, it usually takes 2 to 3 weeks for the first sprouts to poke through the soil. If the weather is particularly cool, it might take a bit longer.
From that point, the growth is rapid. You will see new leaves unfurling every week. Most canna varieties begin blooming about 10 to 12 weeks after planting. Once the blooming starts, it continues in cycles. Each stalk produces a cluster of flowers that open one after another.
Do not be discouraged if your plants start slowly in the spring. As soon as the heat of July and August arrives, cannas truly hit their stride. They thrive in the humidity and high temperatures that cause other garden plants to wilt.
Winter Care: Storing Your Bulbs for Next Year
In warmer climates (USDA zones 8 to 11), cannas can stay in the ground all year long. You simply cut back the foliage after it turns yellow in the fall and wait for them to return in the spring.
However, if you live in zone 7 or colder, the winter freeze will kill the rhizomes if they stay in the ground. The good news is that they are very easy to save for next year. For shipping and timing details, see our Shipping Information. This process is called "lifting."
After the first frost has blackened the foliage, cut the stems down to about 4 inches. Carefully dig up the clump of rhizomes, being careful not to bruise them. Shake off the excess soil and let them air dry in a garage or shed for a few days. Once dry, store them in a box filled with peat moss or sawdust in a cool, dark place that stays above freezing (around 40-50°F is ideal).
Common Questions About Planting Depth
Sometimes gardeners worry that they haven't been precise enough with their measurements. It is helpful to remember that plants are resilient. If you accidentally plant a rhizome 5 inches deep instead of 4, the plant will still grow; it may just take a few extra days to appear.
The main reason we emphasize the 4-inch depth is for stability. Cannas are top-heavy. By mid-August, a tall variety can be 6 feet high with a massive weight of foliage. A rhizome planted too shallowly can actually be pulled out of the soil by the weight of the plant during a heavy rain or windstorm. Getting that initial depth right is like building a strong foundation for a house.
We also find that consistent depth leads to a more uniform look in the garden. If you plant a row of cannas all at the same 4-inch depth, they will likely sprout and bloom at the same time, creating a professional-looking display.
Enhancing Your Garden with Canna Varieties
One of the joys of shopping with us is discovering the wide range of canna colors and patterns available. You don't have to settle for just plain green leaves. Some varieties, like Tropicanna, feature striped leaves in shades of burgundy, gold, and green. Others have dark, chocolate-colored foliage that makes bright red or orange flowers pop.
When planning your garden layout, consider mixing different leaf types. Dark-leaved cannas look stunning when planted next to lime-green ornamentals or bright yellow flowers. Since you now know the correct planting depth and spacing, you can mix and match these varieties with confidence.
Cannas also pair beautifully with other summer-blooming favorites. Try planting them behind a row of dahlias or zinnias. The tall canna foliage provides a textured backdrop that makes the smaller flowers in front stand out even more.
Summary of Canna Planting Success
Creating a tropical escape in your own yard is achievable for any gardener, regardless of experience. By focusing on the fundamentals—sun, water, and proper planting depth—you set the stage for a successful growing season.
Key Steps for Success:
- Wait for soil temperatures to reach 60°F before planting outdoors.
- Select a site with at least 6 hours of full sun.
- Plant the rhizomes 4 inches deep with the eyes facing up.
- Space plants 12 to 24 inches apart depending on the variety.
- Keep the soil consistently moist throughout the summer.
At Longfield Gardens, we take pride in providing high-quality rhizomes that are ready to thrive in your garden. Whether you are a first-time canna grower or a seasoned pro, following these simple rules will ensure your yard is filled with bold, beautiful color all season long. Gardening is about the joy of watching something grow, and few plants offer a more dramatic and rewarding transformation than the canna lily.
Ready to start your tropical garden? Explore our Tall Cannas collection and find the perfect varieties to bring your outdoor space to life this season.
FAQ
Does it matter which way the "eyes" face when planting?
Yes, for the fastest growth, you should plant canna rhizomes with the "eyes" or growth points facing upward. This allows the sprouts to take the shortest path to the soil surface. If you accidentally plant them sideways or upside down, the plant will still grow, but it will use more energy to navigate around the rhizome, which may delay the appearance of the first leaves.
Can I plant cannas in soil that stays wet?
Cannas are unique because they tolerate "wet feet" better than almost any other summer bulb. They can even be planted at the edge of a pond or in boggy areas. However, they still need some oxygen at the root level, so the soil should not be stagnant or foul-smelling. In typical garden beds, ensure the soil is well-draining so the rhizomes don't rot during a particularly rainy spring before they start growing.
How deep should I plant cannas in a pot versus the ground?
The planting depth remains the same whether you are using a container or the ground. Aim for about 4 inches of soil covering the rhizome. In a pot, make sure there is at least several inches of soil underneath the rhizome as well, to allow the roots to grow downward and provide enough weight to keep the pot from tipping over as the plant grows tall.
What happens if I plant my canna bulbs too shallow?
If canna rhizomes are planted too shallow (less than 2 inches deep), the plant may struggle to stay upright as it grows tall. The shallow root system won't provide enough leverage to support the heavy stalks and large leaves, especially in wind or rain. Additionally, shallow rhizomes are more likely to dry out during hot summer days, which can lead to stunted growth and fewer flowers. If you want a second reference on timing and technique, our How Far Apart Should You Plant Canna Bulbs? guide is also helpful.