Can Canna Lilies Grow Outside?

Table of Contents

1. Introduction
2. Understanding Canna Lily Hardiness
3. Selecting the Best Outdoor Spot
4. Timing Your Outdoor Planting
5. How to Plant Canna Lilies Outside
6. Outdoor Care and Maintenance
7. Overwintering: What to Do When the Season Ends
8. Designing Your Outdoor Space with Cannas
9. Common Questions About Outdoor Cannas
10. Conclusion
11. FAQ

Introduction

Bringing a touch of the tropics to your backyard is one of the most rewarding parts of summer gardening. With their oversized, banana-like leaves and brilliant, orchid-like blooms, cannas offer a dramatic architectural element that few other plants can match. At Longfield Gardens, we find that these plants are often the stars of the midsummer garden, providing height and vibrant color when other spring-blooming plants have begun to fade.

Many gardeners wonder if these exotic-looking beauties can actually thrive in a typical backyard setting. This guide is for anyone looking to add bold texture to their landscape, whether you live in a warm southern climate or a northern region with shorter summers. We will cover how canna lilies perform in different environments, the specific conditions they need to flourish outdoors, and how to manage them throughout the changing seasons with options like the Canna Assorted Collection.

Canna lilies can absolutely grow outside in nearly every part of the United States, provided you understand their needs for warmth, water, and sunlight.

Understanding Canna Lily Hardiness

The short answer to whether canna lilies can grow outside is a resounding yes. However, how they grow—and whether they stay outside all year—depends largely on your local climate. These plants are native to tropical and subtropical regions of the Americas, which means they are built for heat and humidity rather than frost and ice.

In USDA hardiness zones 7 through 10, canna lilies are considered perennials. This means they can stay in the ground year-round. In these warmer regions, the foliage may die back after a light frost, but the underground rhizomes (thick, fleshy root structures) remain alive and dormant through the winter, ready to sprout again once the soil warms in the spring. If you want to check your area before planting, the Hardiness Zone Map is a helpful place to start.

In zones 3 through 6, canna lilies are grown as "tender perennials" or summer annuals. They will grow vigorously and bloom beautifully all summer long, but they cannot survive a frozen winter in the ground. For gardeners in these cooler zones, growing cannas outside is a seasonal joy that involves planting in the spring and either replacing them the following year or lifting the rhizomes to store them safely indoors over the winter.

Key Takeaway Canna lilies are tropical plants that thrive outdoors in the heat. While they stay in the ground year-round in warm climates, they must be treated as seasonal guests in cooler northern regions.

Selecting the Best Outdoor Spot

Success with canna lilies begins with choosing the right location. Because they grow so quickly—often reaching several feet in height in just a few months—they have high energy requirements.

Sunlight Requirements

Cannas are sun-worshippers. To produce their best foliage color and the most prolific blooms, they need full sun. In most regions, this means at least six to eight hours of direct, unfiltered sunlight every day. If they are planted in too much shade, the plants tend to become "leggy" as they stretch for light, and they may produce fewer flowers.

In extremely hot climates, such as the desert Southwest, cannas can benefit from a little bit of afternoon shade to prevent the leaf edges from scorching. However, for the majority of US gardeners, the sunniest spot in the yard is usually the best spot for a canna.

Wind Protection

Because cannas have very large, broad leaves, they can act like sails in a high wind. While the stems are remarkably sturdy and rarely need staking, the leaves themselves can tear or become "shredded" during heavy storms or in very windy locations. If your garden is prone to heavy gusts, try to plant your cannas near a fence, a wall, or a line of sturdy shrubs that can provide a bit of a windbreak.

Soil and Drainage

Cannas are not particularly picky about soil pH, but they do best in soil that is rich in organic matter. Before planting, it is a great idea to mix in some compost or well-rotted manure. This provides the nutrients the plants need for their rapid growth and helps the soil retain the moisture that cannas crave.

Unlike many other bulbs and rhizomes that require sharp drainage to prevent rot, cannas are actually quite tolerant of "wet feet." They can grow in boggy areas and are often used near the edges of ponds or water features. However, for standard garden beds, a well-draining soil that stays consistently moist is the ideal middle ground.

Timing Your Outdoor Planting

Timing is everything when it comes to moving canna lilies outside. Because they are tropical, they have no defense against cold soil or frost.

The 60-Degree Rule

The most important factor for planting cannas outside is the soil temperature. You should wait to plant your rhizomes until the soil has warmed to at least 60°F. A good rule of thumb for many gardeners is to plant cannas around the same time you would put tomato plants in the ground. Longfield Gardens’ shipping schedule is also based on USDA hardiness zones, which can help you plan the timing.

If you plant them too early in cold, wet spring soil, the rhizomes may sit dormant for a long time or, in the worst-case scenario, begin to rot before they have a chance to grow. If you want a head start on the season, you can always start your rhizomes in pots indoors four to six weeks before the last frost date and then move the established plants outside once the weather is settled.

What to Expect After Planting

Cannas are famously slow to wake up. Don't be discouraged if you don't see green shoots for two or three weeks after planting. They need consistent warmth to "wake up" the growing points, known as eyes, on the rhizome. Once they do start growing, however, they move fast, often putting on several inches of height per week during the peak of summer.

What to do next

• Check your local frost dates to determine the safest time to plant.
• Use a simple soil thermometer to ensure the ground has reached 60°F.
• Prepare your planting site by clearing weeds and mixing in compost.
• If you have a short growing season, consider starting rhizomes in pots indoors.

How to Plant Canna Lilies Outside

Planting cannas is a straightforward process. Whether you are planting in a garden border or a large container, the goal is to give the rhizome enough space and the right depth to support a tall, heavy plant.

In-Ground Planting

1. Dig the Hole: Dig a hole about 4 to 6 inches deep.
2. Position the Rhizome: Lay the rhizome horizontally in the hole. Look for the "eyes" or small bumps that indicate where the new growth will emerge. Point these upward if possible, but don't worry too much—the plant will find its way to the surface regardless of how it is positioned.
3. Spacing: Space standard canna varieties about 1.5 to 2 feet apart. This might seem like a lot of space initially, but cannas multiply and spread throughout the summer, and they need plenty of room for air circulation.
4. Cover and Water: Cover the rhizome with 2 to 3 inches of soil and firm it down gently with your hands. Water the area well immediately after planting to settle the soil around the rhizome.

Container Planting

Cannas are fantastic container plants, especially the dwarf varieties that stay under 3 feet tall. However, even large varieties can thrive in pots if the container is big enough. For gardeners who want a larger, bolder display, the Tall Cannas collection is a great place to look.

• Use a pot that is at least 15 to 18 inches in diameter for a single rhizome.
• Ensure the pot has drainage holes at the bottom.
• Use a high-quality potting mix rather than garden soil, as it provides the aeration and drainage necessary for healthy root growth.
• Remember that pots dry out much faster than the ground, so container-grown cannas will need more frequent watering.

Outdoor Care and Maintenance

Once your canna lilies are established and growing outside, they are relatively low-maintenance, but they do have a few specific "cravings" that will keep them looking their best.

Watering Correctly

As mentioned earlier, cannas love water. They are one of the few garden plants that are very difficult to overwater during the heat of the summer. In most garden settings, they should receive about an inch of water per week. During the hottest weeks of July and August, you may need to water them every other day, especially if they are growing in sandy soil or containers.

If the leaves start to curl or the edges look brown and crispy, it is usually a sign that the plant is thirsty. Mulching around the base of the plants with straw, bark, or shredded leaves is a great way to help keep the soil moisture levels consistent.

Feeding Your Cannas

Because cannas grow so much biomass in a single season, they are "heavy feeders." To support those massive leaves and constant flowers, we recommend applying a balanced, slow-release fertilizer at planting time. Our team at Longfield Gardens often suggests a second application in midsummer to give the plants a boost for their final flush of blooms.

Alternatively, you can use a water-soluble fertilizer every two to three weeks during the growing season. Look for a formula that is slightly higher in phosphorus to encourage plenty of flower production. Longfield Gardens backs its plants with a 100% Quality Guarantee, which adds peace of mind when you choose quality rhizomes.

Deadheading for More Blooms

Canna flowers grow in clusters at the top of a tall stalk. As the individual flowers fade, they can look a bit messy. "Deadheading" is the process of removing these spent blooms.

• Use scissors or garden snips to remove the old flower where it meets the stem.
• Be careful not to cut off the entire flower spike until all the buds on that spike have finished blooming.
• Once the entire stalk has finished flowering and no more buds are visible, you can cut that stalk back to the foliage level. This encourages the plant to put its energy into new flower stalks rather than producing seeds.

Overwintering: What to Do When the Season Ends

Since canna lilies are tropical, the first frost of autumn is a major turning point. How you handle your plants at this stage depends entirely on your zone.

Warm Climates (Zones 7-10)

If you live in a region where the ground doesn't freeze solid, you can leave your cannas outside. After the first frost turns the foliage brown or black:

1. Cut the stems down to about 4 to 6 inches above the ground.
2. Apply a thick layer (3 to 4 inches) of mulch, such as wood chips or straw, over the area. This acts as an insulating blanket for the rhizomes.
3. In the spring, remove the excess mulch once the danger of frost has passed to allow the soil to warm up.

Cold Climates (Zones 3-6)

In northern regions, the rhizomes must be moved to a frost-free location to survive until next year.

1. The Signal: Wait until a light frost has blackened the foliage. This sends a signal to the plant to go dormant and move its energy down into the rhizome.
2. Lifting: Cut the stems back to about 4 inches. Carefully dig up the clump of rhizomes, starting about a foot away from the center to avoid slicing into the roots.
3. Cleaning: Gently shake off the excess soil. You don't need to wash them, but removing large clumps of dirt makes storage cleaner.
4. Curing: Let the rhizomes sit in a dry, shaded area (like a garage or shed) for a few days to "cure" or dry out slightly.
5. Storing: Place the rhizomes in a box or breathable bag filled with peat moss, vermiculite, or wood shavings. Store them in a cool, dark, dry place where temperatures stay between 40°F and 50°F. A basement or crawl space is often perfect.

Key Takeaway The first frost is your "call to action." Whether you are mulching for the winter or lifting rhizomes for indoor storage, timing your end-of-season care protects your investment for next year.

Designing Your Outdoor Space with Cannas

Because canna lilies are so versatile, they can be used in many different ways in the landscape. Their height and bold texture make them perfect for solving common design challenges.

Creating Privacy Screens

If you have a patio or a seating area that feels a bit too exposed, a row of tall canna lilies can create a "living fence" in just a few months. Varieties that reach 5 to 7 feet tall provide excellent visual screening while adding a lush, green backdrop to your outdoor space.

Adding Vertical Interest

In a garden bed filled with low-growing perennials and annuals, cannas provide much-needed vertical interest. They break up the "flat" look of a garden and draw the eye upward. Try planting them in the center of a circular bed or at the back of a border to create a layered effect.

Pollinator Gardens

You aren't the only one who will enjoy your cannas growing outside. The bright red, orange, and yellow flowers are highly attractive to hummingbirds. Their tubular shape is perfectly designed for a hummingbird's beak. Many bees also visit the flowers for nectar, making cannas a great addition to a wildlife-friendly garden.

Texture and Contrast

The broad, smooth leaves of a canna lily provide a wonderful contrast to the fine textures of ornamental grasses, the lacy foliage of ferns, or the small leaves of traditional bedding plants like lantana or zinnias. If you choose a variety with bronze or variegated foliage, you add another layer of color that remains beautiful even when the plant isn't in bloom.

Common Questions About Outdoor Cannas

While cannas are generally easy to grow, gardeners occasionally run into questions about their performance and health.

Why aren't my cannas blooming?

If your cannas are growing plenty of leaves but no flowers, the most common culprit is a lack of sunlight. Ensure they are getting at least six hours of direct sun. Another possibility is that the soil is too lean; a boost of phosphorus-rich fertilizer can often jumpstart the blooming process. Finally, check your timing—cannas usually need about 10 to 12 weeks of growth before they begin flowering.

Are there pests to worry about?

Cannas are relatively pest-resistant, but they can occasionally attract "leaf rollers"—small caterpillars that stitch the leaves together before they unfurl. If you see leaves that won't open or have small holes in a row, you can manually remove the caterpillars or use a biological control like Bt (Bacillus thuringiensis), which is safe for most other garden inhabitants. In some areas, Japanese beetles may also nibble on the flowers, but these can usually be hand-picked and removed.

Can I grow them in the shade?

While cannas can survive in partial shade, they will not be the showstoppers they are meant to be. The foliage will be less vibrant, the stems will be weaker, and you may only get a few scattered blooms. If you have a shady yard, consider growing them in a large pot on a wheeled caddy so you can move them into the sunniest spot available throughout the day.

Conclusion

Growing canna lilies outside is one of the easiest ways to bring high-impact, tropical beauty to your home garden. Whether you treat them as a permanent fixture in a warm climate or a cherished seasonal guest in the north, their massive leaves and vibrant flowers are sure to spark joy all summer long. By getting the basics right—plenty of sun, consistent moisture, and warm soil—you can enjoy a professional-looking landscape with very little effort.

• Sun and Warmth: Always prioritize a sunny spot and wait for warm soil before planting.
• Water and Food: Keep them hydrated and well-fed to support their rapid growth.
• Winter Care: Know your zone and either mulch or lift your rhizomes when the frost arrives.

Gardening should be a rewarding experience that adds beauty to your life, and canna lilies are the perfect plant to prove that "exotic" doesn't have to mean "difficult." We hope you feel confident in bringing these tropical wonders into your own outdoor space. For more inspiration and high-quality rhizomes to start your season, visit Longfield Gardens and explore the Garden Basic Essentials page for more helpful advice.

"The secret to successful outdoor gardening with cannas is simply matching their tropical soul with a sunny, well-watered spot in your yard."

FAQ

Can canna lilies stay outside in the winter?

This depends entirely on your USDA hardiness zone. In zones 7 through 10, cannas can stay in the ground year-round if they are protected with a thick layer of mulch. In zones 6 and colder, the rhizomes will freeze and rot if left outside, so they must be dug up and stored in a frost-free area for the winter.

Do canna lilies need full sun to grow outside?

Yes, for the best results, canna lilies should receive at least six to eight hours of direct sunlight daily. While they will grow in partial shade, they often become tall and floppy, and their flower production will be significantly reduced. Full sun also helps the colorful foliage of variegated or bronze varieties look its brightest.

How often should I water canna lilies growing outdoors?

Cannas love moisture and should be watered whenever the top inch of soil feels dry. During the peak of summer heat, this often means watering two to three times a week, or even daily for plants in containers. They are very thirsty plants and can even thrive in boggy areas where other plants might struggle with too much water.

When is the best time to plant canna lilies outside?

The best time to plant is in late spring after the danger of frost has passed and the soil has warmed to at least 60°F. Because they are tropical plants, they will not grow in cold soil. For many gardeners, the ideal planting time coincides with when you would typically plant other heat-loving crops like tomatoes or peppers.