Do Canna Lilies Grow in Water? A Guide to Aquatic Gardening

Table of Contents

1. Introduction
2. Understanding the Aquatic Nature of Cannas
3. Why Grow Cannas in Water?
4. How to Plant Canna Lilies in Water
5. Sunlight and Temperature Requirements
6. Feeding Your Aquatic Cannas
7. Maintenance and Care
8. Choosing the Best Varieties for Water
9. Overwintering Cannas Grown in Water
10. Common Myths About Cannas in Water
11. Summary of Success
12. FAQ

Introduction

There is something truly magical about the sight of lush, tropical foliage rising elegantly from the edge of a garden pond. If you have ever admired the bold leaves and brilliant blooms of a canna lily, you might have wondered if these sun-loving plants can survive with their roots submerged. The answer is a resounding yes. Many gardeners are surprised to learn that canna lilies are not just for flower beds; they are actually outstanding candidates for water features and boggy areas.

At Longfield Gardens, we enjoy helping homeowners discover new ways to use classic plants to create a more beautiful landscape. Growing cannas in water is one of the easiest ways to add a dramatic, high-impact focal point to your yard without the constant need for a watering can. Whether you have a large koi pond or a simple container water feature on your patio, these versatile plants can thrive. If you're shopping for a good starting point, our Tall Cannas collection is a natural place to explore.

This guide is designed for anyone looking to expand their gardening horizons by moving cannas into the water. We will cover which varieties work best, the simple steps to get them established, and how to maintain them for a season full of vibrant color. By the end of this article, you will know exactly how to use cannas to turn your water feature into a tropical paradise.

Cannas are remarkably adaptable plants that can bridge the gap between land and water with ease.

Understanding the Aquatic Nature of Cannas

Most people think of cannas as purely terrestrial plants. While it is true that they grow beautifully in traditional garden soil, their history tells a different story. Many species of cannas are native to the wetlands and marshy areas of North and South America. This means they are naturally equipped to handle "wet feet," which is a gardening term for plants that enjoy having their root systems in saturated soil.

In the world of water gardening, cannas are classified as "marginals." These are plants that grow best in the shallow water found along the edges of a pond. In nature, these plants help stabilize the banks and provide cover for aquatic life. In your home garden, they provide height and architectural interest that many other aquatic plants lack. For more growing basics, the Learn hub is a helpful place to continue reading.

While almost any canna can tolerate wet soil for a short period, certain varieties are specifically bred for life in the water. These are often referred to as "water cannas" or Canna glauca hybrids. They have been selected for their ability to thrive in low-oxygen environments and their resistance to rot when submerged. However, even the standard varieties you might find in a typical landscape can often be transitioned to water if you follow the right steps.

The Difference Between Terrestrial and Water Cannas

When you are browsing for rhizomes, you might see some labeled specifically as aquatic varieties. These plants, such as the famous Longwood hybrids, were developed specifically to live in water year-round. They often have slightly narrower leaves and a more refined growth habit than their land-dwelling cousins.

Terrestrial cannas, which are the most common types found in garden centers, are bred for performance in well-drained soil. Can these grow in water too? Usually, the answer is yes, but they require a bit more care during the transition. If you take a dry rhizome and drop it directly into deep water, it may struggle. If you start that same rhizome in a pot of soil first and then move it into the water once it has sprouted, it will likely flourish.

Key Takeaway: Cannas are natural "marginal" plants, meaning they love the shallow edges of ponds and can grow successfully in water if they are properly established first.

Why Grow Cannas in Water?

Growing cannas in water offers several advantages that you won't get from planting them in a traditional garden bed. For many busy gardeners, the primary benefit is the simplified maintenance. Because the plant is sitting in water, the risk of the soil drying out is completely eliminated. Cannas are notoriously thirsty plants, and in a hot summer, they can require daily watering. In a pond, they take exactly what they need, whenever they need it.

Beyond the ease of care, cannas act as natural filters for your water feature. Like many aquatic plants, they absorb excess nutrients from the water, such as nitrogen and phosphorus. These nutrients often come from fish waste or decaying organic matter and can lead to algae blooms if left unchecked. By "starving" the algae of these nutrients, your cannas help keep your pond water clearer and healthier. If you want another practical gardening reference, see our Shipping Information page for order timing and zone-based details.

The aesthetic impact is also hard to beat. Most pond plants are relatively low-growing, such as lilies that float on the surface or irises that reach only a foot or two in height. Cannas provide much-needed vertical interest. A tall canna variety can reach five or six feet, creating a stunning backdrop for smaller aquatic plants. The reflection of their vibrant orange, red, or yellow flowers on the surface of the water adds a layer of beauty that you simply cannot get in a standard border.

Quick Benefits of Aquatic Cannas

• No manual watering required once established.
• Natural filtration helps reduce algae growth in ponds.
• Adds dramatic height and tropical texture to water features.
• Provides shade and hiding spots for pond fish and frogs.

How to Plant Canna Lilies in Water

Planting a canna in water is slightly different than planting one in the ground, but it is not complicated. The goal is to provide the plant with a stable base and access to nutrients while keeping the rhizome at the correct depth.

We recommend starting your cannas in pots before placing them in your pond. This gives the plant a chance to develop a strong root system and some initial foliage, which makes it much more resilient once it is submerged.

Step 1: Choose the Right Container

You will need a sturdy plastic pot for your canna. A five-gallon bucket or a large nursery pot (at least 10–12 inches in diameter) is ideal. If you are placing the pot in a decorative pond, you may want to use a "no-hole" aquatic pot or a mesh pond basket. Mesh baskets are popular because they allow water to flow freely through the roots, but they can be messy if you use standard potting soil.

Step 2: Use the Correct Planting Medium

This is a critical step. Do not use standard, lightweight potting mix that contains perlite or vermiculite. These materials are designed to float, and they will drift out of the pot and create a mess in your pond.

Instead, use a heavy garden soil or a specialized aquatic planting medium. A soil with a high clay content is actually preferred here because it stays at the bottom of the pot and provides a stable anchor for the roots. Some gardeners even use plain gravel or pea stone, though this requires more frequent supplemental feeding since gravel contains no nutrients.

Step 3: Planting the Rhizome

Place your canna rhizome about 3 to 4 inches deep in the soil. Ensure the "eyes" or growing points are facing upward. If you are planting a variety that has already sprouted, make sure the base of the green stem is covered by at least an inch of soil. Firm the soil down well to remove any large air pockets.

Step 4: Adding a Top Layer

To keep the soil from washing away and to prevent fish (like curious koi) from digging up the rhizome, add a one-inch layer of decorative gravel or river stones to the top of the pot. This acts as a "mulch" for your aquatic plant and keeps everything looking tidy.

Step 5: Placement and Depth

Now you are ready to move the pot into the water. The most common mistake is placing the plant too deep. Most cannas prefer to have only 0 to 6 inches of water over the top of the pot.

If your pond is deeper than 6 inches, don't worry. You can use bricks or overturned plastic crates to create a "shelf" for the pot to sit on. This allows the roots to stay submerged while keeping the crown of the plant near the surface where it can get plenty of oxygen.

What to Do Next:

1. Select a heavy, clay-based soil rather than standard potting mix.
2. Plant the rhizome 4 inches deep in a sturdy 12-inch pot.
3. Top with gravel to prevent soil from floating away.
4. Submerge the pot so the water is no more than 6 inches above the soil line.

Sunlight and Temperature Requirements

Even though they are growing in water, cannas still have the same basic needs as their terrestrial counterparts. The most important of these is sunlight. To produce those iconic, brilliant blooms and maintain lush foliage, cannas need a minimum of 6 to 8 hours of direct sunlight every day. For more on light levels, see our guide on Can Cannas Grow in the Shade?.

If they are placed in a shaded corner of a pond, they may still grow, but they will likely become "leggy" (tall and thin) and may fail to flower. Sunlight also helps keep the water temperature warm, which cannas love. These are tropical plants, and they do their best growing when the water temperature is consistently above 65°F.

Timing Your Planting

Because cannas are sensitive to cold, you should wait until the danger of frost has passed and the water in your pond has begun to warm up before placing them outside. In most regions, this is usually in late May or early June.

If you live in a cooler climate, you can get a head start by potting your cannas indoors in April. Place them in a sunny window or under a grow light and keep the soil moist. By the time the pond is ready, you will have a well-established plant ready to take off. If you want to check how your timing fits your region, use the Hardiness Zone resources on our site.

Feeding Your Aquatic Cannas

Cannas are "heavy feeders," meaning they require a lot of nutrients to fuel their rapid growth and large flowers. In a traditional garden, you might use a granular fertilizer worked into the soil. In a pond, you have to be a bit more strategic to avoid clouding the water or causing an algae spike.

The best way to fertilize cannas in water is to use aquatic fertilizer tablets or spikes. These are designed to be pushed deep into the soil of the pot, near the root zone. They release nutrients slowly over several weeks without leaching into the surrounding pond water.

We suggest feeding your cannas once a month during the peak growing season (June through August). This ensures they have the energy to keep producing new flower spikes until the first frost. If you notice the leaves starting to look pale or yellow, it is usually a sign that the plant needs a boost of nutrients.

Maintenance and Care

One of the reasons we love cannas at Longfield Gardens is how rewarding they are for the minimal effort they require. Once your cannas are settled into their aquatic home, maintenance is very straightforward.

Deadheading for More Blooms

To keep your plants looking their best and to encourage more flowers, you should practice "deadheading." When a flower cluster has finished blooming and begins to fade, simply cut the flower stalk back. Be careful not to cut the entire stem down to the ground, as new flower buds often form just below the first cluster. Removing the old flowers prevents the plant from putting energy into seed production and redirects it back into creating more beautiful blossoms.

Managing Growth

Cannas are vigorous growers. In a single season, one rhizome can turn into a massive clump. If you find that your canna is outgrowing its pot or becoming too top-heavy, you can easily divide it. This is best done in the spring before the plant starts its main growth spurt, but it can be done mid-season if necessary. Simply lift the pot, remove the plant, and use a sharp spade or garden knife to cut the rhizome into smaller sections.

Pests to Watch For

While cannas are generally very hardy, they can occasionally be visited by pests like the canna leaf roller. This is a small caterpillar that rolls itself up inside the leaves, preventing them from opening properly. Because the plant is in water, you want to be very careful about using sprays. The safest method is to simply unroll the leaves and remove the caterpillars by hand. Keeping the foliage clean and removing any dead leaves promptly will also help prevent pest issues.

Key Takeaway: Regular deadheading and monthly aquatic fertilizer tabs are the "secret" to keeping your water-grown cannas blooming all summer long.

Choosing the Best Varieties for Water

While many cannas will adapt to water, some are proven performers that we consistently recommend for their reliability and beauty. If you are looking for specific varieties to add to your water feature, keep an eye out for these types.

The Longwood Series

Named after the famous Longwood Gardens in Pennsylvania, these hybrids were bred specifically for aquatic environments. They are the "gold standard" for pond gardening.

• Canna Tall Pretoria: Features boldly striped foliage and brilliant orange flowers.
• Canna Tall Tropicanna: Offers bold, multi-colored leaves with shades of purple, pink, and green.
• Canna Tall Tropicanna Gold: Brings golden-striped foliage and a dramatic tropical look.

Multi-Colored Foliage Varieties

If you want your water feature to look tropical even when the plants aren't in bloom, look for varieties with variegated leaves.

• Canna Tall Australia: This is a bold, dark-foliage canna with vibrant red flowers.
• Canna Tall Stuttgart: A striking foliage variety with strong ornamental presence.
• Canna Tall Tropicanna Black: Its deep burgundy leaves make a dramatic contrast at the water’s edge.

Dwarf Varieties

If you have a small patio pond or a "pond-in-a-pot," you may want to stick with dwarf cannas. These typically stay under 2 or 3 feet tall, making them less likely to tip over in the wind. Look for the 'Cannova' or 'Puck' series, which offer compact growth without sacrificing flower size. For a broader mix of plants, our Canna Assorted Collection can also be useful.

Overwintering Cannas Grown in Water

Cannas are tender perennials. This means that in USDA hardiness zones 8 and warmer, they can often stay in the water year-round. However, for most of us in cooler climates (zones 3 through 7), the rhizomes will freeze and rot if left in the pond over winter.

The process of overwintering aquatic cannas is very similar to terrestrial ones, with one extra step to account for the moisture. If you want to compare the company’s policy and plant guarantee before ordering, see About Us.

When to Lift Your Cannas

Wait until the first light frost has blackened the foliage. This signal tells the plant to go dormant and move its energy down into the rhizome. Once the leaves have turned brown, cut the stems down to about 4 to 6 inches above the soil line.

Storage Steps

1. Lift the Pot: Remove the pot from the water and let it drain for a day or two in a frost-free area like a garage.
2. Clean the Rhizomes: You can either leave the rhizomes in their pots of soil or remove them and wash off the dirt. Many water gardeners find it easier to leave them in the pots, as long as the soil is kept barely damp (not soaking wet) throughout the winter.
3. Find a Cool, Dark Spot: Store the pots or rhizomes in a cool, dark place where temperatures stay between 40°F and 50°F. An unheated basement or a crawlspace is usually perfect.
4. Check Periodically: Every month or so, check on your rhizomes. If the soil is bone-dry, add a tiny bit of water. You want them to stay dormant, but you don't want them to shrivel up completely.

In the spring, once the weather warms up, you can bring the pots back out into the sun, start watering them, and the cycle begins again.

Common Myths About Cannas in Water

There are a few misconceptions that sometimes hold gardeners back from trying this method. Let's clear those up.

Myth 1: They will rot if they stay in water. As long as the water is not stagnant and the plant is getting enough sunlight, cannas are very resistant to rot. The key is to avoid submerging the plant too deep too quickly. Let it grow an inch or two above the water line, and it will be fine.

Myth 2: You need a huge pond. Not at all. You can grow a canna in a large, decorative pot filled with water on your balcony. As long as the roots are wet and the sun is shining, the canna doesn't care how big the "pond" is.

Myth 3: They attract mosquitoes. While standing water can attract mosquitoes, a healthy pond with cannas usually does the opposite. The plants help create an ecosystem that supports dragonflies and other beneficial insects that eat mosquito larvae. If you are using a small container, simply adding a "mosquito dunk" (a natural Bti product) will keep the water clear of larvae without harming the plant.

Summary of Success

Growing canna lilies in water is a rewarding way to bring a touch of the tropics to your backyard. By understanding their natural love for "wet feet" and providing them with plenty of sunshine and a little bit of food, you can enjoy a spectacular display of foliage and flowers all summer long.

We stand behind the quality of our plants at Longfield Gardens, and we want you to feel confident in your gardening journey. Remember that gardening is an experiment, and cannas are some of the most forgiving plants you can work with. Whether you are planting them in a traditional garden bed or tucking them into the edge of a pond, they are sure to provide the "wow" factor you are looking for. If you want to review our plant promise, visit our guarantee page.

Next Steps for Your Water Garden:

• Choose a sunny spot in your water feature that gets at least 6 hours of light.
• Select a "Water Canna" hybrid or a vigorous variety like 'Bengal Tiger'.
• Follow the "heavy soil and gravel" potting method to keep your water clear.
• Enjoy the low-maintenance beauty of a plant that waters itself!

FAQ

Can I put a canna lily that is currently growing in my garden into my pond?

Yes, you can transition a terrestrial canna to a pond. It is best to dig it up, wash the soil off the roots, and replant it in a pot with heavy clay soil or gravel. Slowly introduce it to the water by placing it on a shallow shelf first so it can adapt to the higher moisture levels without going into shock.

Do I need to use special soil for aquatic cannas?

You should avoid standard potting mixes because they contain floating materials like perlite. A heavy garden soil with high clay content or a specialized aquatic planting mix is best. This ensures the soil stays in the pot and provides a solid anchor for the tall, heavy stems of the canna lily.

How deep should the water be over my canna lily pot?

Ideally, the water should be between 0 and 6 inches deep over the top of the pot. While some established water cannas can handle slightly deeper water, most varieties perform best when the "crown" (where the stems meet the roots) is close to the surface where oxygen levels are higher.

Will canna lilies survive the winter in a pond?

In most parts of the United States, canna lilies will not survive the winter if left in the water. Once the first frost hits, you should remove the pots from the pond and store the rhizomes in a cool, frost-free place until spring. Only in very warm climates (Zone 8 and above) can they remain in the pond year-round.