Table of Contents
- Introduction
- Choosing the Perfect Location
- Timing Your Planting
- How to Plant Canna Rhizomes
- Essential Care for Summer Success
- Growing Cannas in Containers
- Managing Common Challenges
- End of Season Care and Overwintering
- Creating Beautiful Combinations
- Conclusion
- FAQ
Introduction
There is nothing quite like the dramatic, architectural beauty of cannas to transform a standard backyard into a lush, tropical oasis. With their oversized, banana-like leaves and vibrant flower spikes, these plants bring a sense of excitement and scale to the summer garden that few other perennials can match. Whether you are looking to create a private backyard screen or add a pop of saturated color to your patio containers, cannas are a rewarding choice for gardeners of all skill levels.
At Longfield Gardens, we want to help you achieve success with these sun-loving giants by focusing on a few simple basics. While their appearance suggests they might be difficult to maintain, cannas are actually quite sturdy and vigorous when their primary needs for heat and moisture are met. This guide will walk you through everything you need to know, from selecting the right planting spot to successfully overwintering your rhizomes for next year.
The following canna growing tips are designed for the home gardener who wants maximum impact with straightforward, practical steps. By understanding how these plants grow and what they crave most, you can enjoy a season of non-stop color and impressive foliage.
Choosing the Perfect Location
Success with cannas starts with choosing the right spot in your yard. Because these plants are native to tropical and subtropical regions, they have specific preferences for light and protection from the elements.
Prioritize Full Sun
The single most important factor for healthy cannas is sunlight. To produce their best leaf color and a steady supply of flowers, they need full sun. In most regions, this means at least six to eight hours of direct, unfiltered sunlight every day. While cannas can grow in partial shade, they often become "leggy," meaning the stems grow too tall and weak as they reach for the light. This can cause the plants to flop over during a summer storm. Additionally, varieties grown for their colorful or variegated foliage will show much more intense patterns when they receive plenty of sun.
Protection from the Wind
Cannas are famous for their large, expansive leaves. While beautiful, these leaves act like sails in the wind. If you live in a particularly breezy area, try to plant your cannas near a fence, a wall, or a sturdy row of shrubs. This protection helps prevent the leaves from shredding or tearing, which can give the plant a ragged appearance. If the leaves do get a bit of wind damage, it does not usually hurt the health of the plant, but a sheltered spot keeps them looking their best all season long.
Soil and Drainage
In the wild, many cannas grow near the edges of ponds or in damp, marshy areas. This means they are much more tolerant of "wet feet" than many other garden bulbs. They prefer rich, fertile soil that is high in organic matter. If your soil is heavy clay or very sandy, you can improve it by mixing in a few inches of compost or well-rotted manure before planting.
While they enjoy moisture, the soil should still have decent drainage so the rhizomes do not sit in stagnant, freezing water in the early spring. "Drainage" simply refers to how quickly water moves through the soil. A good test is to watch your planting area after a heavy rain; if the water disappears within an hour or two, the drainage is likely fine for cannas.
Key Takeaway: For the most vibrant colors and strongest stems, place your cannas in a sunny, sheltered spot with rich soil that stays consistently moist.
Timing Your Planting
When it comes to cannas, patience is a virtue. Because they are tropical plants, they are very sensitive to cold temperatures. Planting them too early in cold, damp soil can cause the rhizomes to rot before they even have a chance to sprout.
The 60-Degree Rule
The best time to plant cannas outdoors is when the soil has warmed up to at least 60°F. A good rule of thumb is to wait until the same time you would plant tomatoes or peppers in your garden. In most parts of the United States, this is well after the danger of the last spring frost has passed.
If you are unsure about your soil temperature, you can use a simple soil thermometer. Push it about two to three inches into the ground in the morning. If it consistently reads 60°F or higher, your cannas are ready to go into the ground.
Starting Cannas Early Indoors
If you live in a northern climate with a short growing season, you might want to give your cannas a head start. You can do this by planting the rhizomes in pots indoors about four to six weeks before your last frost date.
Use a high-quality potting mix and place the containers in a warm, sunny window or under grow lights. Once the weather warms up and the soil outside is ready, you can move these started plants into the garden. This "head start" method often results in earlier blooms and larger plants by mid-summer.
What to do next:
- Check your local frost dates to determine your safe planting window.
- Observe your garden's sun patterns to find the brightest spot.
- Purchase a soil thermometer if you want to be precise with your timing.
How to Plant Canna Rhizomes
Cannas grow from thick, fleshy underground stems called rhizomes. These are often mistaken for bulbs, but they grow horizontally just beneath the soil surface.
Preparing the Rhizomes
When you receive your shipment from us at Longfield Gardens, your canna rhizomes will be ready for planting. You may notice small bumps or points on the rhizome; these are called "eyes," and they are the points where new growth will emerge.
If you have a very large rhizome, you can sometimes divide it into smaller pieces, provided each piece has at least two or three healthy eyes. However, for the best first-year results, it is usually easiest to plant the rhizome whole as it was received.
Depth and Spacing
Getting the depth and spacing right is a quiet winner when it comes to garden success.
- Depth: Dig a hole about 4 inches deep. Place the rhizome in the hole horizontally. It doesn't matter much which way the eyes are pointing, as the plant will naturally find its way toward the sun, but pointing them upward can give the plant a slight advantage. Cover the rhizome with 2 to 3 inches of soil.
- Spacing: Cannas need room to breathe and expand. For standard, tall varieties, space them about 18 to 24 inches apart. If you are planting dwarf varieties, you can place them closer together, about 12 inches apart.
Initial Watering
After planting, give the area a good soak to settle the soil around the rhizome. After that initial watering, you can wait until you see the first green shoots peeking through the soil before you start a regular watering schedule. This prevents the rhizome from getting too much water while it is still dormant.
Essential Care for Summer Success
Once your cannas are established and growing vigorously, they require very little specialized care. However, because they grow so fast and large in a single season, they have high demands for "fuel"—specifically water and nutrients.
Watering Correctly
Cannas are thirsty plants. To keep those large leaves lush and prevent the edges from turning brown or "scorched," you need to keep the soil consistently moist. During the heat of summer, this may mean watering every few days, or even daily if they are in containers.
The best way to water is deeply and at the base of the plant. This encourages the roots to grow deep into the soil. Avoid frequent, shallow sprinkles, which only wet the surface and can lead to weaker plants. If you use mulch, such as shredded bark or compost, it will help hold that moisture in the soil longer.
Feeding Your Cannas
Because cannas produce so much foliage and many large flowers in just a few months, they are often called "heavy feeders." They benefit from regular applications of fertilizer.
At the time of planting, you can mix a slow-release fertilizer into the soil. Once the plants are about a foot tall, you can begin using a balanced, water-soluble fertilizer every two to three weeks. Following the instructions on the product label will ensure your plants get exactly what they need without overdoing it.
Deadheading for More Blooms
Deadheading is the simple act of removing spent flowers before they turn into seed pods. This is one of the best canna growing tips for extending the beauty of your garden. When a flower fades, use a pair of clean garden snips to cut off the individual flower or the entire flower spike once all the buds have finished.
By removing the old flowers, you signal to the plant that it should keep producing more blooms rather than putting its energy into making seeds. Canna stems often produce multiple clusters of flowers. When you are deadheading, be careful not to cut off the new buds that are often waiting right behind the old ones.
Key Takeaway: Keep cannas well-watered and well-fed throughout the summer to support their rapid growth and continuous blooming.
Growing Cannas in Containers
If you don't have a large garden bed, or if you want to bring a tropical look to your porch or poolside, cannas are excellent candidates for container gardening.
Selecting the Right Pot
Because cannas grow tall and have a heavy root system, you need a substantial pot. A container that is at least 12 to 18 inches in diameter is a good starting point for a single rhizome. Ensure the pot has drainage holes at the bottom so excess water can escape.
Using a heavy pot made of ceramic or terra cotta can be helpful, as cannas can become top-heavy when they reach their full height. A light plastic pot might tip over in a strong wind once the plant is five feet tall.
Potting Mix and Care
Use a high-quality, well-draining potting mix rather than garden soil, which can be too heavy and compact in a container. Because pots dry out faster than the ground, you will need to check the moisture level of your container-grown cannas frequently. In the height of summer, they may need water both morning and evening.
Container-grown plants also need more frequent fertilizing because nutrients leach out of the soil every time you water. Using a liquid fertilizer every 10 to 14 days will keep your potted cannas looking vibrant and healthy.
Managing Common Challenges
Cannas are generally very tough, but like any plant, they can occasionally face challenges. Most issues are easily solved with simple adjustments.
Pests and Leaves
The most common pest for cannas is the leaf roller. This is a small caterpillar that weaves a bit of silk to "roll" the leaf shut, protecting itself while it eats. If you see leaves that aren't unfurling properly or have small holes in a neat row, you may have leaf rollers. You can often simply unroll the leaf and remove the caterpillar by hand, or use an organic spray recommended by your local extension service.
Slugs and snails also enjoy the tender young shoots of cannas in the spring. If you notice ragged edges on new growth, a bit of organic slug bait or a simple barrier can keep them at bay.
Foliage Color Issues
If your canna leaves look pale or yellow instead of deep green or vibrant bronze, the plant may be hungry or thirsty. Check your watering schedule and ensure you are fertilizing regularly. Sometimes, very hot afternoon sun can "scorch" the edges of the leaves if the plant isn't getting enough water to keep up with the evaporation. Increasing your watering frequency usually solves this.
End of Season Care and Overwintering
In USDA zones 8 through 11, cannas are generally hardy and can stay in the ground all year. In zone 7, they often survive with a thick layer of mulch. However, if you live in zone 6 or colder, you will need to "lift" and store the rhizomes if you want to grow them again next year.
When to Lift Rhizomes
The signal to begin winter storage is the first frost. A light frost will turn the canna foliage black or brown. This doesn't hurt the rhizome; it actually tells the plant it's time to go dormant.
Once the foliage has been hit by frost, cut the stems down to about 4 to 6 inches above the ground. Leave them for a few days to let the energy move down into the rhizome, then gently lift them out of the soil with a garden fork or spade. Be careful not to bruise or cut the fleshy rhizomes as you dig.
Cleaning and Drying
Shake off the excess soil and let the rhizomes sit in a dry, shaded area (like a garage or shed) for a few days to "cure." This drying period helps the outer skin toughen up, which prevents rot during storage. You don't need to wash them with water; in fact, keeping them dry is better.
Storage Conditions
Store your rhizomes in a cool, dark, and frost-free place. An unheated basement or a crawlspace that stays between 40°F and 50°F is ideal.
- Place the rhizomes in a cardboard box or a plastic bin with ventilation holes.
- Surround them with a dry material like peat moss, perlite, or wood shavings. This keeps them from touching each other and helps manage any minor moisture.
- Check them once a month during the winter. If they look very shriveled, you can lightly mist the packing material with a tiny bit of water. If any pieces look soft or rotten, discard them immediately so the rot doesn't spread.
What to do next:
- Mark your calendar for the average first frost date in your area.
- Gather storage supplies like cardboard boxes and peat moss in late summer.
- Label your rhizomes by color or variety name before storing so you know what is what in the spring.
Creating Beautiful Combinations
Cannas are spectacular on their own, but they also play well with other plants. Their bold texture makes them a perfect backdrop for finer-textured flowers.
- For a Tropical Look: Pair cannas with elephant ears, hibiscus, and caladiums. The mix of massive leaves in different shapes creates an instant jungle vibe.
- In a Border: Place tall cannas at the back of a flower bed. In front of them, plant mid-sized flowers like zinnias or salvia. The cannas provide a solid wall of color that makes the smaller flowers pop.
- With Ornamental Grasses: The contrast between the broad canna leaves and the airy, wispy blades of ornamental grasses is very sophisticated and adds movement to the garden.
Conclusion
Growing cannas is one of the easiest ways to bring a bold, high-impact look to your summer landscape. By following these canna growing tips—focusing on plenty of sun, consistent moisture, and proper timing—you can enjoy these tropical treasures regardless of where you live. Whether you treat them as annuals or choose to save the rhizomes from year to year, the reward is a garden filled with vibrant color and impressive scale.
- Choose a sunny, protected spot to keep foliage and flowers looking their best.
- Wait for warm soil before planting to ensure healthy, rapid growth.
- Water and fertilize regularly to support these hungry, thirsty giants.
- Deadhead spent blooms to keep the flowers coming all season long.
We at Longfield Gardens are proud to provide high-quality rhizomes to help you start your journey. Remember that gardening is a rewarding process of discovery, and cannas are some of the most forgiving and spectacular plants you can choose to grow.
"Cannas are the architectural anchors of the summer garden, providing height, color, and a sense of wonder that lasts from the first summer heat until the arrival of frost."
Ready to add some drama to your yard? Start planning your sunny border or patio containers today and get ready for a tropical summer.
FAQ
How long does it take for cannas to bloom after planting?
Most cannas will begin blooming about 10 to 12 weeks after they sprout. Since they are slow to start in cool weather, your first flowers usually appear in mid-summer and will continue until the first frost of autumn.
Do I need to soak canna rhizomes before planting?
Soaking is not necessary for canna rhizomes. As long as you plant them in warm, moist soil and give them an initial watering, they will have all the hydration they need to break dormancy and begin growing.
Why are my canna leaves turning brown on the edges?
Brown edges, often called "leaf scorch," are usually a sign that the plant is thirsty or that the air is very dry. Ensure you are watering deeply and frequently during hot weather, and consider adding a layer of mulch to help the soil retain moisture.
Can I leave my cannas in the ground over winter?
This depends entirely on your USDA hardiness zone. If you live in Zone 8 or warmer, you can usually leave them in the ground with a protective layer of mulch. If you live in Zone 7 or colder, it is best to lift the rhizomes and store them indoors to protect them from freezing temperatures.