How to Grow Cannas for a Tropical Summer Garden

Table of Contents

1. Introduction
2. Understanding Cannas
3. Finding the Perfect Spot
4. When to Plant Cannas
5. How to Plant Canna Rhizomes
6. Essential Summer Care
7. Growing Cannas in Containers
8. End of Season Care and Overwintering
9. Beautiful Canna Varieties to Try
10. Troubleshooting Common Issues
11. The Joy of Growing Cannas
12. FAQ

Introduction

There is nothing quite like the sight of a canna lily unfurling its massive, paddle-shaped leaves in the heat of July. These plants bring an immediate sense of the tropics to any backyard, offering architectural height and vibrant, jewel-toned flowers that last until the first frost. At Longfield Gardens, we love how cannas transform a standard garden bed into a lush, exotic escape with very little effort from the gardener. If you're ready to shop, start with our Tall Cannas collection.

Whether you are looking to create a living privacy screen or want to add a bold focal point to your patio containers, cannas are the perfect choice. They are remarkably resilient, fast-growing, and thrive in the heat of a North American summer. This guide will walk you through everything you need to know to successfully grow these summer showstoppers, from choosing the right spot to overwintering your plants for next year. For a broader overview, see All About Cannas.

With a few simple steps, you can enjoy a season full of dramatic foliage and nectar-rich blooms that hummingbirds adore. Growing cannas is an easy way to achieve high-impact results in your landscape.

Understanding Cannas

Cannas are often called "canna lilies," but they are not true lilies at all. They are actually more closely related to gingers and bananas. This relationship is obvious when you look at their thick, fleshy stems and broad leaves. In the gardening world, we categorize them as tender perennials. This means they can live for many years, but they are sensitive to freezing temperatures.

While many people refer to the "bulbs" of a canna, they actually grow from rhizomes. A rhizome is a thick, underground stem that grows horizontally just beneath the soil surface. These rhizomes act as energy storage units, fueling the plant’s rapid growth once the weather warms up.

One of the best things about cannas is their versatility. They come in a wide range of sizes, from dwarf varieties that stay under two feet tall to giants that can reach heights of eight feet in a single season. Their foliage is just as varied, with colors ranging from deep emerald green and blue-gray to bronze, burgundy, and even multi-colored stripes. For a mixed planting option, explore our Canna Assorted Collection.

Finding the Perfect Spot

Getting the location right is the most important part of learning how to grow cannas. These plants are sun-seekers and heat-lovers. If you give them what they need at the start, they will reward you with massive growth and plenty of flowers.

Sunlight Requirements

Cannas need full sun to perform their best. In most regions, this means at least six to eight hours of direct sunlight every day. If they are planted in too much shade, the plants tend to become "leggy," stretching toward the light and potentially flopping over. You will also notice fewer flowers and less vibrant leaf colors on plants kept in the shade.

Soil and Drainage

In the wild, many canna species grow near the edges of ponds and wetlands. This tells us two things: they love moisture and they can handle soil that stays a bit damp. However, for the best results in a home garden, we recommend a spot with rich, fertile soil that drains well enough to prevent the rhizomes from sitting in stagnant water during the dormant season.

If your soil is heavy clay, you can improve it by mixing in some compost or well-rotted manure before planting. This adds nutrients and improves the soil structure. If you have a naturally boggy area in your yard, cannas are one of the few flowering plants that will thrive there during the summer months.

Wind Protection

Because cannas have such large, soft leaves, they can sometimes be damaged by strong, persistent winds. The leaves may tear or develop ragged edges, which gardeners often call "shredding." If your yard is particularly windy, try to plant your cannas near a fence, a wall, or a grouping of sturdy shrubs that can act as a windbreak.

Key Takeaway: Choose a sunny, sheltered spot with rich soil that stays consistently moist to ensure your cannas reach their full potential.

When to Plant Cannas

Timing is everything when it comes to planting tender rhizomes. Because cannas are tropical in nature, they have no defense against frost. Planting too early in cold, wet soil can cause the rhizomes to rot before they ever have a chance to sprout.

The Tomato Rule

A good rule of thumb is to wait until the same time you would plant tomatoes or peppers in your garden. This is usually a few weeks after the last expected spring frost. For most gardeners, this is when the soil temperature has reached a consistent 60°F.

If you want to be precise, you can use a soil thermometer. Dig a small hole about two or three inches deep and check the temperature in the morning. If it is consistently at or above 60°F, your cannas are ready to go into the ground.

Starting Early Indoors

If you live in a region with a short growing season, you can give your cannas a head start by potting them up indoors. About four to six weeks before the last frost, 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. For zone-based timing, see our Shipping Information.

How to Plant Canna Rhizomes

Planting cannas is a straightforward process. Because the rhizomes are large and sturdy, they are very easy to handle.

Preparation

Before you start digging, take a look at your rhizomes. You will notice several small bumps or points on the surface. These are called "eyes," and they are the points where new growth will emerge. If the rhizomes are very large and have many eyes, you can carefully break or cut them into smaller sections, making sure each piece has at least two or three healthy eyes.

Step-by-Step Planting

1. Loosen the Soil: Use a garden fork or spade to loosen the soil to a depth of about 12 inches. Mix in a few inches of compost if your soil needs a nutrient boost.
2. Dig the Hole: Dig a shallow hole about four inches deep.
3. Position the Rhizome: Place the rhizome in the hole horizontally. While it is best to point the eyes upward, don't worry too much if you can't tell which way is up. The plant is smart enough to find the light and will grow toward the surface regardless of how it is positioned.
4. Space Them Out: Cannas need room to breathe and expand. Space large varieties about 18 to 24 inches apart. For dwarf varieties, 12 to 15 inches is usually sufficient.
5. Cover and Tamp: Fill the hole with soil and gently press down with your hands to remove any large air pockets.
6. Water Lightly: Give the area a light watering to settle the soil.

Essential Summer Care

Once your cannas are in the ground and the weather warms up, they will grow surprisingly fast. To keep them looking their best, follow these simple care steps.

Watering for Success

Cannas are thirsty plants. Unlike many other garden flowers that prefer to dry out between waterings, cannas like to stay consistently moist. During the heat of the summer, you may need to water them every few days, or even daily if they are in containers.

The goal is to keep the soil feeling like a wrung-out sponge. If the leaves start to curl or the edges turn brown and crispy, it is a sign that the plant is too dry. Applying a two-inch layer of mulch around the base of the plants will help retain moisture and keep the roots cool.

Feeding Your Plants

Think of cannas as "heavy eaters." Because they produce so much foliage and so many flowers in a single season, they require a lot of fuel. We recommend applying a balanced, slow-release fertilizer at planting time.

For an extra boost, you can use a water-soluble fertilizer once a month throughout the growing season. Look for one with a slightly higher nitrogen content if you want to maximize leaf growth, or a balanced formula to encourage both leaves and blooms.

Deadheading and Grooming

To keep your cannas looking tidy and to encourage more flowers, you should practice "deadheading." This simply means removing the spent blooms before they have a chance to form seed pods.

Canna flowers grow in clusters on a long stalk. When an individual flower fades, snip it off. Once the entire stalk has finished blooming, you can cut the stalk back to the next set of leaves. This prevents the plant from wasting energy on seed production and keeps the focus on creating more vibrant flowers.

If the lower leaves of the plant start to look yellow or tattered as the season progresses, you can simply prune them off near the main stem. This won't hurt the plant and will keep the display looking fresh.

What to Do Next:

• Check soil moisture every few days during hot weather.
• Remove faded flowers weekly to prolong the blooming season.
• Apply mulch to help the soil stay moist and cool.

Growing Cannas in Containers

If you don't have a lot of garden space, or if you want to add a tropical touch to your porch or poolside, cannas are excellent candidates for container gardening.

Choosing the Right Pot

Because cannas grow tall and have a heavy root system, you need a substantial pot. For a single standard-sized canna, look for a container that is at least 15 to 18 inches in diameter. Larger pots are better because they hold more soil and moisture, which prevents the plants from drying out too quickly.

Make sure the pot has drainage holes. Even though cannas like water, they don't want to sit in a pot that acts like a bucket without an exit for excess rain.

Planting and Placement

Use a high-quality, well-draining potting mix rather than garden soil. Potting mix is lighter and designed to provide the right balance of air and moisture for container plants. Plant the rhizome about three to four inches deep in the center of the pot.

Place your containers in the sunniest spot possible. Remember that pots heat up faster than the ground, so you will need to be extra diligent about watering. On very hot days, container-grown cannas may need water both in the morning and the evening.

Designing with Cannas

Cannas are the ultimate "thriller" in the classic "thriller, filler, spiller" container design. Their height and bold texture make them the perfect centerpiece. You can surround them with "fillers" like lantana or coleus, and "spillers" like sweet potato vine or trailing petunias for a professional-looking arrangement. For more container inspiration, see How to Grow and Style Phasion Canna Bulbs.

End of Season Care and Overwintering

As autumn approaches and the first frost nears, it is time to think about how to handle your cannas for the winter. Your approach will depend entirely on where you live.

In Warm Climates (Zones 7–10)

If you live in USDA hardiness zones 7 through 10, you are in luck! Cannas can generally stay in the ground all year round. After the first frost turns the foliage brown, simply cut the stems down to about four inches above the ground. Apply a thick layer of mulch—about four to six inches of straw or shredded leaves—over the top of the planting area. This acts as a blanket to protect the rhizomes from any occasional deep freezes.

In Cold Climates (Zones 6 and Lower)

In colder regions, canna rhizomes will freeze and turn to mush if left in the ground over the winter. To save them for next year, you will need to "lift" and store them.

1. Wait for Frost: Let the first frost blacken the leaves. This signals to the plant that it is time to go dormant.
2. Cut Back: Use garden shears to cut the stems down to about four or five inches.
3. Dig Carefully: Use a shovel or garden fork to gently lift the entire clump of rhizomes out of the ground. Start digging about a foot away from the stems to avoid accidentally slicing the rhizomes.
4. Clean and Dry: Shake off any excess soil. You don't need to wash them perfectly; a little bit of soil is fine. Let the rhizomes sit in a dry, frost-free place (like a garage or shed) for a few days to "cure." This helps the outer skin toughen up.
5. Store: Place the rhizomes in a cardboard box or a plastic bin filled with slightly damp peat moss, perlite, or wood shavings. You want the storage medium to be just barely moist—not wet.
6. Winter Check-ins: Store the box in a cool, dark place where temperatures stay between 40°F and 50°F. A basement or crawl space is usually ideal. Every month or so, check on them. If they look shriveled, mist them lightly with water. If you see any soft or rotten spots, cut them away and discard the affected pieces.

Key Takeaway: Overwintering is a simple way to preserve your favorite canna varieties and grow an even bigger display every year.

Beautiful Canna Varieties to Try

At Longfield Gardens, we offer a selection of cannas that have been trialed for performance and beauty. Here are a few types to consider for your garden:

• Tropicanna (Phasion): Perhaps the most famous canna, known for its incredible variegated leaves with stripes of green, gold, pink, and red. It features bright orange flowers. For another bold foliage option, browse the Tall Cannas collection.
• Wyoming: A classic variety with dark, bronze-purple foliage and large, vibrant orange blossoms. It is a tall, stately plant that makes a great backdrop.
• Picasso: A stunning dwarf variety with green leaves and bright yellow flowers that are heavily speckled with red dots. It is perfect for containers. If you prefer a more compact look, see our Canna Medium collection.
• Striata (Pretoria): This variety features bright green leaves with vivid yellow veins and striking orange flowers. It is very energetic and adds a bright pop of color.
• Tropicanna Black: For those who love dark foliage, this variety offers deep burgundy, nearly black leaves that make the scarlet-orange flowers truly stand out. You can also explore Canna Tall varieties for similar dramatic selections.

Troubleshooting Common Issues

While cannas are generally easy to grow, you might encounter a few minor hurdles. Most can be solved with simple changes in care.

Lack of Flowers

If your canna is growing plenty of leaves but no flowers, the most likely culprit is a lack of sunlight. Ensure the plant is getting at least six hours of direct sun. Another possibility is a lack of nutrients; make sure you are using a balanced fertilizer. Finally, ensure you are watering enough. A stressed, dry plant will often stop producing blooms to conserve energy.

Ragged or Holes in Leaves

If you see small holes or "trails" in the leaves, you may have canna leaf rollers. These are the larvae of a small moth that rolls the leaf up and eats it from the inside. You can often manage them by simply unrolling the leaf and removing the caterpillar, or by using an organic spray like Bacillus thuringiensis (Bt). Japanese beetles may also nibble on the flowers and leaves; these can be hand-picked and dropped into a bucket of soapy water.

Yellowing Leaves

While old leaves will naturally turn yellow and die off, a widespread yellowing of young leaves might indicate a drainage problem. If the soil is waterlogged and lacks oxygen, the roots can begin to rot. Check the moisture level and ensure the water is able to move through the soil.

The Joy of Growing Cannas

Gardening should be a rewarding experience, and few plants offer as much "wow factor" for as little work as the canna. From the moment the first leaf spike pokes through the soil to the final flourish of flowers in the autumn, these plants are a constant source of beauty.

By following these simple guidelines, you can create a stunning tropical landscape right in your own yard. Whether you are a beginner or an experienced gardener, cannas provide a reliable way to add color, texture, and height to your outdoor space.

At Longfield Gardens, we take pride in providing high-quality rhizomes that are ready to thrive in your garden. We stand behind the quality of our plants and want to ensure you have a successful and enjoyable growing season.

Next Step: Browse our collection of canna rhizomes and choose a few varieties to bring a tropical touch to your garden this year. If you want a ready-made mix, start with the Canna Assorted Collection.

FAQ

How deep should I plant canna rhizomes?

You should plant canna rhizomes about three to four inches deep. If you are planting in a container, four inches is ideal to provide enough stability for the tall stems as they grow.

Do cannas need to be soaked before planting?

While it is not strictly necessary, soaking your canna rhizomes in lukewarm water for a few hours before planting can help "wake them up" and encourage faster sprouting. However, they will grow perfectly well without this step as long as the soil is warm and moist.

Why aren't my cannas blooming?

The most common reason for a lack of blooms is insufficient sunlight. Cannas need at least six hours of direct sun to produce flowers. Other factors include poor soil nutrition or a lack of consistent water during the hottest parts of the summer.

Can I leave my cannas in the ground during winter?

This depends on your location. In USDA zones 7 through 10, you can usually leave cannas in the ground with a thick layer of protective mulch. In zone 6 and colder, the rhizomes will freeze, so you should dig them up and store them in a frost-free area for the winter. For planting and shipping timing by zone, review the Shipping Information.