Introduction
There is a unique thrill in watching the first pointed shoots of a canna lily break through the warm spring soil. As the days grow longer, these small spikes unfurl into massive, paddle-shaped leaves that bring an immediate sense of the tropics to any backyard. While green-leaved varieties are lovely, purple canna bulbs offer something truly special: a deep, moody foliage color that serves as a dramatic backdrop for vibrant summer blooms.
At Longfield Gardens, we enjoy helping gardeners find these high-impact plants that provide beauty from late spring until the first frost. Whether you are looking to fill a large garden bed or want to add a splash of sophisticated color to your patio containers, these dark-leaved beauties are a fantastic choice. This guide will help you understand how to choose, plant, and care for purple-foliaged cannas to ensure your garden looks its best all season long.
Canna lilies are among the hardest-working plants in the summer garden. They thrive in the heat, grow with incredible speed, and ask for very little in return for their spectacular display. By focusing on a few simple care steps, you can transform your outdoor space into a lush, colorful retreat. For help timing your order, see our Shipping Information.
Why Choose Purple Canna Bulbs?
When gardeners search for purple canna bulbs, they are usually looking for varieties with dark, dramatic foliage. While most canna flowers lean toward shades of red, orange, yellow, and pink, the "purple" designation typically refers to the leaves. These leaves can range from a smoky bronze to a deep, glossy burgundy or even a dark chocolate brown.
The contrast provided by dark foliage is one of the most effective tools in garden design. In a sea of green garden plants, the deep tones of a purple-leaved canna make every other color pop. Hot colors like orange and scarlet look more intense against dark leaves, while cool colors like lime green or silver appear much brighter.
Beyond their beauty, these plants are incredibly resilient. They are fast-growing perennials that love the sun and can handle the high humidity of American summers. Because they grow from thick, starchy structures called rhizomes—which many people refer to as bulbs—they have the energy reserves needed to produce massive amounts of growth in a single season. If you want to match plants to your climate, our Hardiness Zone Map can help.
Popular Varieties with Dark Foliage
Understanding the different varieties available helps you pick the right height and color for your space. While there are many cultivars, some are specifically known for their exceptional dark foliage.
Canna 'Australia'
Many enthusiasts consider this the gold standard for dark-leaved cannas. 'Australia' features leaves that are a deep, satin-like burgundy-black. The foliage remains dark throughout the entire season, even in intense sun. It is topped with glowing red flowers that create a sophisticated, high-contrast look.
Canna 'Tropicanna Black'
This variety is famous for its rich, chocolate-colored leaves. The foliage is exceptionally broad and serves as a magnificent anchor for the mandarin-red flowers. It is a vigorous grower that works well at the back of a flower bed or as a center-piece in a large container. You can also browse the Tall Cannas collection for more dramatic vertical accents.
Canna 'Wyoming'
'Wyoming' offers a slightly different take on the dark foliage theme. Its leaves are a beautiful bronze-purple with a bit of a translucent quality when the sun hits them from behind. The flowers are a vibrant, cheerful orange. It is a taller variety, often reaching five feet or more, making it perfect for creating a living privacy screen.
Canna 'Cleopatra'
While 'Cleopatra' is known for its unpredictable "splashed" flowers (which can be yellow, red, or both), the foliage is equally fascinating. Some leaves may be green, while others are dark purple, or even half-green and half-purple. It is a great choice for gardeners who love a bit of mystery and variety in their plant displays. The Canna Medium Cleopatra page shows this unique look.
Key Takeaway: When selecting purple canna bulbs, focus on the foliage color. Varieties like 'Australia' and 'Tropicanna Black' offer the deepest burgundy and bronze tones, providing a stunning contrast to their bright red or orange flowers.
Right Plant, Right Place: Site Selection
Success with purple canna bulbs begins with choosing the right location. Because these plants are native to tropical and subtropical regions, they have specific preferences that are easy to meet if you plan ahead.
Sunlight Requirements
Cannas are sun-worshipers. To achieve the deepest purple and bronze colors in the foliage, they need full sun. This means at least six to eight hours of direct sunlight every day. In areas with less light, the leaves may lose some of their dark pigment and turn more greenish-bronze. Furthermore, the plants will produce fewer flowers if they are tucked away in the shade.
Soil and Drainage
"Drainage" is a term gardeners use to describe how quickly water moves through the soil. While cannas love moisture, they do best in soil that is rich in organic matter but doesn't stay soggy like a swamp. If you have heavy clay soil, you can improve it by adding compost or well-rotted manure before planting. This helps the soil hold the right amount of moisture while allowing the roots to breathe.
Wind Protection
Because cannas have such large, paddle-shaped leaves, they can catch the wind like a sail. In very windy locations, the leaves may tear or become ragged. If possible, plant them near a fence, a wall, or a group of sturdy shrubs that can provide a bit of a windbreak. This keeps the foliage looking pristine throughout the summer.
How to Plant Purple Canna Bulbs
Planting cannas is a straightforward process that yields big rewards. Since we ship our premium rhizomes at the ideal time for your specific climate, you can feel confident that they are ready to grow once they arrive.
When to Plant
Timing is the most important factor when planting cannas. These are warm-weather plants that cannot tolerate frost. Wait to plant your rhizomes until the danger of frost has passed and the soil temperature has reached at least 60°F. A good rule of thumb is to plant your cannas at the same time you would put tomato plants in the ground.
Planting Depth and Spacing
Getting the depth right ensures the rhizome stays insulated and stable while it sends up new shoots.
- Depth: Dig a hole about 4 inches deep. Place the rhizome in the hole with the "eyes" (the small bumps or sprouts) pointing upward.
- Covering: Cover the rhizome with 2 to 3 inches of soil.
- Spacing: Cannas spread as they grow. Space standard varieties about 1 to 2 feet apart. If you are planting in a container, you can place them a bit closer, but ensure the pot is large enough to accommodate their vigorous growth.
Starting Early Indoors
If you live in a northern region with a short growing season, you can give your purple canna bulbs a head start. About four to six weeks before the last frost date, plant the rhizomes in pots filled with moist potting soil. Keep them in a warm, sunny spot indoors. By the time the weather warms up, you will have established plants ready to go into the garden, which leads to earlier blooms. For other practical growing tips, visit our canna care guide.
What to Do Next:
- Check your local frost dates to determine your planting window.
- Select a spot that receives at least 6 hours of direct sun.
- Amend the soil with compost to ensure it is rich and well-draining.
- Plant rhizomes 4 inches deep with the eyes facing up.
Essential Care for Maximum Growth
Once your purple cannas are in the ground, they are relatively self-sufficient. However, because they grow so much in a single season, they appreciate a little extra attention in two areas: water and food.
Watering Correctly
Cannas are thirsty plants. In their native habitats, they often grow near water sources. During the heat of the summer, ensure they receive at least 1 to 2 inches of water per week. If you are growing them in containers, you may need to water them every day, as pots dry out much faster than garden beds.
The goal is to keep the soil consistently moist. If you notice the edges of the leaves starting to turn brown or "burn," it is often a sign that the plant is not getting enough water. Mulching around the base of the plants with bark or straw can help keep the moisture in the soil where it belongs.
Fertilizing for Success
Think of cannas as the "heavy hitters" of the garden. To produce those massive leaves and constant flowers, they need plenty of nutrients. Start by mixing a balanced, slow-release fertilizer into the soil at planting time. Once the plants are about a foot tall, you can begin using a water-soluble fertilizer every two to three weeks to keep them fueled for the season.
Deadheading and Maintenance
"Deadheading" is the practice of removing spent flowers. While some modern canna varieties are "self-cleaning," most benefit from having the old blossoms snipped off. This prevents the plant from putting energy into making seeds and encourages it to produce more flower spikes. When a whole flower stalk has finished blooming, cut it back to the next side-shoot or to the base of the plant to keep it looking tidy.
Managing Common Canna Challenges
While cannas are generally easy-to-grow plants, they do have a few common visitors you should know about. We believe that a proactive approach is always easier than a reactive one.
Canna Leafrollers
The most common pest for these plants is the canna leafroller. These are small caterpillars that stitch the edges of the leaves together before they unfurl, eating the leaf from the inside.
The easiest way to manage them is to keep an eye on your plants as new leaves emerge. If you see a leaf that looks "stuck" or has small holes in a row, simply unroll it and remove the caterpillar by hand. For larger plantings, a biological control like Bacillus thuringiensis (Bt), which is a naturally occurring soil bacterium, can be very effective when applied according to the label instructions.
Slugs and Snails
Because cannas love moist environments, they can sometimes attract slugs and snails, especially when the plants are young and the leaves are close to the ground. You can protect your plants by using copper tape around containers or by applying a pet-safe slug bait around the base of the plants in the garden. Once the plants grow taller, slugs are rarely an issue.
Leaf Spots and Rust
In very humid climates with poor air circulation, cannas can sometimes develop fungal issues like rust, which looks like small orange spots on the undersides of leaves. The best fix is prevention: space your plants correctly to allow for air movement and avoid watering the foliage directly. Instead, apply water at the base of the plant.
Overwintering Purple Canna Bulbs
In USDA hardiness zones 8 through 11, canna rhizomes can usually stay in the ground all year. A thick layer of mulch in the fall is often all the protection they need. However, for gardeners in zones 7 and colder, these tropical plants will not survive the winter outdoors.
Digging and Storing
Fortunately, "lifting" cannas for the winter is a simple process that allows you to enjoy the same plants year after year.
- Wait for Frost: Allow the first light frost to blacken the foliage. This tells the plant to move its energy down into the rhizome for dormancy.
- Cut Back: Cut the stems down to about 2 to 4 inches above the ground.
- Dig Gently: Use a garden fork to gently lift the clump of rhizomes out of the soil. Be careful not to bruise or cut the "bulbs."
- Clean and Dry: Shake off excess soil and let the rhizomes dry in a shady, well-ventilated area for a few days. This "cures" the skin and helps prevent rot.
- Store: Place the rhizomes in a cardboard box or a breathable bag filled with slightly damp peat moss, perlite, or wood shavings. Store them in a cool, dark place (like a basement or crawlspace) where temperatures stay between 40°F and 50°F.
Check on your stored bulbs once or twice during the winter. If they look shriveled, mist them lightly with water. If any look soft or mushy, remove them so the rot doesn't spread to the healthy ones. For step-by-step storage help, see our overwintering canna bulbs guide.
Key Takeaway: In colder climates, digging up canna rhizomes after the first frost is an easy way to save your favorite varieties. Store them in a cool, dry place in peat moss to keep them healthy until spring.
Design Ideas for Purple Cannas
The dark foliage of purple canna bulbs offers endless design possibilities. Because they are architectural and tall, they function as the "thriller" in many garden compositions.
The Tropical Border
Pair purple cannas with other large-leafed plants like elephant ears (Colocasia) and hardy hibiscus. The contrast between the dark canna leaves and the huge green leaves of an elephant ear creates an instant jungle vibe. Add some orange or red lantana at the base to pull the flower colors together.
Sophisticated Containers
For a modern look, plant a single purple canna variety like 'Australia' in a large, slate-gray or metallic pot. Surround the base with a lime-green trailing plant like 'Marguerite' sweet potato vine. The "neon" green of the vine against the dark burgundy of the canna is a show-stopping combination. If you are planning pots and planters, our container-growing guide has useful details.
Privacy Screens
Because varieties like 'Wyoming' grow so quickly, you can use them to create a temporary summer privacy screen. Plant them in a row along a patio or a property line. By July, you will have a dense wall of beautiful foliage and flowers that blocks the view and adds a splash of color.
Supporting Pollinators
It’s not just humans who love cannas! The bright, tubular flowers are a favorite of hummingbirds and butterflies. By planting purple cannas, you are providing a valuable nectar source for these visitors throughout the hottest part of the summer when other flowers might be fading. For more inspiration, browse our cannas blog category.
Conclusion
Purple canna bulbs are one of the most rewarding additions you can make to your summer garden. With their dramatic foliage and vibrant blossoms, they provide a level of visual impact that few other plants can match. By following the simple rules of giving them plenty of sun, water, and food, you can enjoy a tropical oasis right in your own backyard.
At Longfield Gardens, we take pride in providing high-quality rhizomes that are true to variety and ready to thrive in your garden. Gardening is a journey of discovery, and there is no better way to start the season than by planting something bold and beautiful.
- Choose dark-leaved varieties for maximum color contrast.
- Plant in full sun after the soil has warmed up.
- Keep the soil moist and provide regular fertilizer.
- Lift and store rhizomes in cold climates to enjoy them next year.
"A garden filled with the deep, rich tones of purple cannas feels both sophisticated and adventurous. These plants are proof that you don't need a green thumb to achieve professional-looking results."
Ready to start your own tropical retreat? We invite you to explore our selection of cannas and find the perfect purple variety for your garden today.
FAQ
Can I grow purple cannas in pots?
Yes, cannas thrive in containers as long as the pots are large enough. Use a container that is at least 15 to 18 inches in diameter and has drainage holes. Because pots dry out quickly, be sure to water your container-grown cannas daily during the heat of the summer and provide a liquid fertilizer every few weeks.
Why are the leaves on my purple canna turning green?
The most common reason for this is a lack of sunlight. The dark pigments (anthocyanins) in the leaves require direct sun to develop fully. If a plant is moved to a shadier spot, it will often produce more chlorophyll to compensate, which turns the leaves green. Ensure your plants get at least 6 to 8 hours of sun for the best color.
When will my canna bulbs start to bloom?
Cannas typically begin blooming in mid to late summer, roughly 60 to 90 days after planting. The exact timing depends on the weather and how warm the soil is. If you want earlier blooms, you can start your rhizomes indoors in pots about a month before your last frost date.
Do I need to cut back my cannas in the summer?
You don't need to do a major pruning, but "deadheading" is very helpful. Removing spent flowers prevents the plant from forming seeds and encourages it to send up new flower spikes. If a leaf becomes damaged by wind or pests, you can also snip it off at the base to keep the plant looking its best.
