Table of Contents
- Introduction
- Understanding the Canna Lily's Natural Affinity for Water
- Can All Canna Lilies Grow in Water?
- Choosing the Best Varieties for Your Water Feature
- How to Plant Canna Lilies in a Pond
- Managing Stability and Growth
- Maintaining Your Water Cannas
- Using Cannas in Other Wet Environments
- Why We Love Cannas for Water Gardening
- Conclusion
- FAQ
Introduction
There is something uniquely satisfying about the bold, architectural presence of canna lilies in the garden. Their oversized, tropical leaves and vibrant blooms bring an immediate sense of lushness to any space. Many gardeners are surprised to learn that these sun-loving beauties are not just for traditional garden beds. Because of their natural history and origins in tropical wetlands, cannas are actually quite comfortable in very wet environments.
At Longfield Gardens, we enjoy seeing how home gardeners push the boundaries of design by incorporating these versatile plants into different landscapes. Whether you have a dedicated backyard pond, a small container water feature, or a damp "rain garden" spot that stays soggy after a storm, cannas can be a fantastic choice. We want to help you understand which varieties will thrive in these conditions and how to set them up for success.
This guide will answer the question of whether all cannas can grow in water and provide the practical steps needed to transition them to an aquatic setting. We will cover the specific needs of water-loving varieties, the best planting techniques for ponds, and how to maintain them throughout the season. Ultimately, you will see that with a few simple adjustments, canna lilies can become the crown jewel of your water garden.
Understanding the Canna Lily's Natural Affinity for Water
To understand why canna lilies are so successful in water, it helps to look at where they come from. Most species are native to the tropical and subtropical regions of the Americas, where they often grow along the edges of rivers, marshes, and wetlands. In these natural habitats, their roots (rhizomes) are frequently submerged or situated in soil that is constantly saturated.
Because of this heritage, cannas have evolved to be "heavy drinkers." While many other summer-blooming bulbs might rot if they sit in water, cannas have a specialized root structure that allows them to thrive in low-oxygen, high-moisture environments. This characteristic makes them one of the most adaptable plants for the modern gardener.
However, there is a distinction between "enjoying wet soil" and "living in a pond." While almost all cannas love "wet feet"—meaning soil that is consistently moist—not every variety is equally prepared to live with its rhizome entirely underwater for months at a time. Understanding this nuance is the first step toward a thriving water display.
Can All Canna Lilies Grow in Water?
The short answer is that most canna lilies can tolerate growing in water, but they must be managed correctly. While nearly any standard garden canna can adapt to a bog-like environment, there is a specific group of hybrids known as "Water Cannas" that are bred specifically for life in ponds.
Terrestrial vs. Aquatic Cannas
Most of the cannas you find in garden centers are considered terrestrial or "garden" cannas. These are bred for their flower size, leaf color, and height in standard soil. These varieties will grow exceptionally well in damp soil and can even transition to shallow water if they are already actively growing.
On the other hand, true Water Cannas are often hybrids of Canna glauca. These were famously developed through breeding programs, such as those at Longwood Gardens, to create plants that are specifically suited for submerged conditions. These varieties often have narrower, more lance-shaped leaves and are exceptionally vigorous when placed in a pond environment.
The Importance of "Active Growth"
A critical rule for any canna you plan to put in water is that it should never be submerged while it is a dormant rhizome. If you place a bare, dormant rhizome directly into cold pond water, it is highly likely to rot before it has a chance to wake up.
For the best results, we recommend starting your cannas in pots with standard potting soil first. Once the plant has developed a few sets of leaves and a healthy root system, it is much better equipped to handle the transition to a water feature. This simple step ensures the plant is strong enough to process the moisture and begin its rapid summer growth.
Key Takeaway: While most canna lilies can adapt to water, they perform best if they are already growing before being submerged. Specific "Water Canna" hybrids are the most reliable choice for deep-water placement.
Choosing the Best Varieties for Your Water Feature
When selecting a canna for a water feature, you can choose based on your aesthetic goals. Because cannas in water tend to grow even faster and taller than those in the ground, you should consider the scale of your pond or container.
- Longwood Hybrids: These are the gold standard for water gardening. Look for varieties like 'Endeavour' (red flowers), 'Erebus' (salmon pink), 'Ra' (bright yellow), and 'Taney' (burnt orange). They are specifically bred to stay healthy in aquatic environments.
- Variegated Foliage Types: Varieties like Tropicanna or Bengal Tiger are stunning in water. The reflection of their striped orange, green, and yellow leaves on the water's surface creates a high-impact look.
- Dwarf Varieties: If you have a small patio pond or a "spilling" water feature, dwarf cannas are a smart choice. They provide the same tropical look but stay around 2 to 3 feet tall, making them less likely to tip over in the wind.
How to Plant Canna Lilies in a Pond
Planting in a pond is different from planting in a garden bed. You aren't just digging a hole; you are creating a stable environment for a plant that will become quite top-heavy as it matures.
Step 1: Use the Right Pot
Choose a sturdy plastic nursery pot. It should be large enough to accommodate the rhizome's growth but not so large that it is difficult to move. A 2-gallon or 5-gallon pot is usually sufficient for a single large canna. Make sure the pot has plenty of drainage holes to allow water to circulate through the root zone.
Step 2: Selecting the Soil
Avoid using standard "potting mix" that contains perlite or vermiculite. These materials are designed to be lightweight and will float right out of the pot, creating a mess in your pond. Instead, use a heavy garden soil or a specialized aquatic planting medium. Some gardeners even use plain unscented kitty litter (the clay-based kind) or heavy clay soil from their own yard.
Step 3: Planting the Rhizome
If you are starting with a pre-grown plant, simply transplant it into the heavy soil at the same depth it was previously growing. If you are starting from a rhizome, plant it about 2 to 3 inches deep. Pack the soil firmly around the roots to provide stability.
Step 4: Adding a "Cap"
Once the canna is in the pot, add a 1-inch layer of pea gravel or small river rocks on top of the soil. This "cap" serves two purposes: it keeps the soil from washing away into the pond and prevents fish (like koi) from digging up the rhizomes.
Step 5: Placement and Depth
Lower the pot slowly into the water. For most cannas, the ideal depth is 2 to 6 inches of water over the top of the pot. While some Water Cannas can handle deeper placement, keeping them in the shallow "marginal" zone of the pond ensures they get plenty of warmth and oxygen.
What to do next:
- Start your cannas in pots indoors or in a warm spot 4-6 weeks before the pond water warms up.
- Wait until the pond water temperature is consistently above 65°F before placing your plants.
- Secure the pots with heavy stones if your pond has a liner to prevent them from tipping.
- Ensure the spot receives at least 6 to 8 hours of direct sunlight.
Managing Stability and Growth
One of the most common issues when growing cannas in water is their tendency to catch the wind. Because they grow so vigorously with a constant water supply, they can easily reach 5 or 6 feet in height.
In a pond, a tall plant acts like a sail. If the pot isn't heavy enough, a stiff breeze can tip it over. To prevent this, you can place the planting pot inside a larger, heavier decorative crock, or wedge the pot between large rocks in your pond’s shelf. If a plant does tip over, simply stand it back up and check that the "cap" of gravel is still intact.
Another growth factor is the sheer speed of development. Cannas are "heavy feeders" as well as heavy drinkers. In a pond with fish, the plants will naturally filter out excess nutrients (nitrates) from the water, which helps keep the pond clean. However, if your leaves start to look pale or yellow, you may need to add aquatic fertilizer tabs. These are pushed deep into the soil of the pot so they don't dissolve directly into the open water and cause an algae bloom.
Maintaining Your Water Cannas
Water gardening with cannas is remarkably low-maintenance once the plants are established. You don't have to worry about wilting or watering schedules, which is a major benefit during hot summer months.
Pruning and Deadheading
To keep your water feature looking its best, remove spent flowers regularly. This process, called deadheading, encourages the plant to produce more blooms rather than putting energy into seed production. Simply cut the flower stalk back to the next set of leaves. You should also trim away any yellowing or tattered leaves to maintain a tidy appearance.
Pest Monitoring
While cannas are generally hardy, they can occasionally be visited by the canna leaf roller (a small caterpillar). In a water setting, you have to be careful about what treatments you use to avoid harming fish or beneficial pond insects. The best approach is usually mechanical: simply snip off any leaves that appear to be rolled up or "stitched" together and dispose of them.
Overwintering Steps
Cannas are tropical plants and will not survive a freeze. In most US climates, you will need to bring them in for the winter.
- Timing: Wait until the first frost kills back the foliage.
- Removal: Lift the pots out of the water. This is a great time to divide the rhizomes if the pot has become crowded.
- Storage: Cut the stalks down to about 4 inches. You can store the entire pot in a cool, frost-free basement or garage (around 40-50°F). Keep the soil barely moist—not soggy—throughout the winter.
- Alternative: Some gardeners prefer to remove the rhizomes from the soil, clean them, and store them in peat moss or wood shavings.
Key Takeaway: Stability is the biggest challenge for cannas in water. Use heavy pots, cap them with stones, and enjoy the natural water-filtering benefits these plants provide.
Using Cannas in Other Wet Environments
If you don't have a pond, you can still take advantage of the canna's love for water. Many home landscapes have "problem areas" where water collects after rain or where the soil stays perpetually damp.
Rain Gardens
Rain gardens are designed to catch and filter runoff from roofs or driveways. Because cannas can handle both temporary flooding and periods of relative dampness, they are excellent candidates for the "basin" area of a rain garden. Their deep roots help break up heavy soil and improve drainage over time.
Container Water Features
You can create a "pond in a pot" on your patio using a sealed ceramic planter with no drainage holes. Fill it with water and place a potted canna inside. This is an easy way to add vertical interest and a tropical vibe to a small deck or balcony without the commitment of a full-scale pond.
Why We Love Cannas for Water Gardening
At Longfield Gardens, we believe that gardening should be a rewarding and enjoyable experience. Using cannas in water features is a perfect example of how choosing the right plant for the right place can lead to spectacular results with minimal effort.
The presence of cannas in a pond adds a layer of height and texture that is hard to achieve with traditional lilies or floating plants. They provide shade for fish, help balance the pond's ecosystem by consuming excess nutrients, and offer a long season of color. Whether you are a seasoned pond enthusiast or a beginner looking to experiment with a patio water feature, cannas are a forgiving and high-reward choice.
Conclusion
While not every canna is sold as a "water plant," almost all of them possess the genetic potential to thrive in wet conditions. By starting with actively growing plants, using the correct potting techniques, and ensuring they have plenty of sunlight, you can enjoy these tropical giants in a variety of aquatic settings. Remember that the key to success is warmth; wait for the summer sun to heat your water before introducing your cannas to their new home.
We invite you to explore the many colors and patterns available in our collection. With a little bit of planning, you can transform a simple water feature into a lush, tropical oasis that blooms all summer long.
- Choose Water Canna hybrids for the most reliable pond performance.
- Always use heavy soil and a gravel cap to keep pond water clear.
- Provide 6-8 hours of sun for the best flower production.
- Lift and store rhizomes before the first hard frost to enjoy them again next year.
"The secret to a stunning water garden is often found in the plants that bridge the gap between land and water. Cannas do this with more style and vigor than almost any other summer bloom."
Ready to start your tropical water garden? Browse our selection at Longfield Gardens and find the perfect varieties to bring your vision to life.
FAQ
1. Can I put a potted canna directly into my pond?
Yes, you can place a potted canna into a pond, but it should already be actively growing with several leaves. Do not put a dormant rhizome directly into the water, as it may rot. Ensure the pot uses heavy soil (not a floating mix) and is capped with gravel to prevent the soil from clouding the water. For planting basics, see How Deep Should You Plant Canna Bulbs?.
2. Do cannas clean pond water?
Cannas are excellent for pond health because they are vigorous growers that consume large amounts of nutrients like nitrates and phosphates. By "eating" these nutrients, they help compete with algae, which can lead to clearer water. They also provide helpful shade and cover for fish. If you are planning a mixed planting, How Many Canna Bulbs Per Container? can help with spacing ideas.
3. Will cannas survive winter in the water?
No, cannas are tropical plants and will die if their rhizomes freeze. In most regions, you must remove the pots from the water before the first hard frost. You can then store the rhizomes in a cool, dry, frost-free location like a basement or garage until spring. For more seasonal guidance, review the Hardiness Zone Map.
4. Why is my water canna falling over?
Cannas in water often grow very tall and become top-heavy, making them prone to catching the wind. To prevent this, use a heavy pot or place the pot inside a larger, weighted decorative container. You can also wedge the pot between heavy rocks on a pond shelf to provide extra stability. For more help with tall plants, see How Far Apart Should You Plant Canna Bulbs?.