Table of Contents
- Introduction
- Why Cannas Thrive in Aquatic Environments
- Choosing the Best Cannas for Water Planting
- When to Move Cannas into Your Pond
- Step-by-Step Guide: How to Plant Cannas in Water
- Caring for Your Aquatic Cannas
- Managing Growth and Stability
- Dividing and Propagation
- Dealing with Common Challenges
- Overwintering Your Aquatic Cannas
- The Versatility of Canna "Wet Feet"
- Summary of Success
- FAQ
Introduction
There is something truly magical about the sight of lush, tropical foliage rising directly out of a shimmering pond. Cannas are famous for their bold leaves and vibrant, orchid-like flowers that bring a splash of the tropics to any backyard. While many gardeners enjoy growing them in traditional flower beds, you might be surprised to learn how well they adapt to aquatic environments. If you’re shopping for canna varieties, Longfield Gardens has several options to explore.
At Longfield Gardens, we love helping you find new and exciting ways to use your favorite plants. Cannas are naturally versatile, and their ability to thrive with "wet feet" makes them a fantastic choice for water features, bog gardens, and even submerged pots. Whether you have a small patio fountain or a sprawling garden pond, these plants can add vertical drama and bright color where other flowers might struggle. For more growing basics, our Learn page is a helpful place to start.
This guide will explain exactly how to grow cannas in water, from choosing the right varieties to the best planting techniques for success. We will cover how to transition your plants to an aquatic lifestyle and how to keep them blooming all summer long. If you have ever wondered if your cannas could make the leap from the soil to the water, the answer is a resounding yes.
Why Cannas Thrive in Aquatic Environments
To understand why cannas grow so well in water, it helps to look at where they come from. Most canna species are native to the tropical and subtropical regions of the Americas. In these areas, they often grow along the edges of rivers, marshes, and wetlands. They are naturally adapted to soil that stays consistently moist or even saturated for long periods.
In a garden setting, this means cannas are far more tolerant of "wet feet" than most other summer-blooming bulbs. While many plants would suffer from root rot if left in standing water, cannas often respond with faster growth and larger leaves. The constant access to moisture allows them to maintain their lush appearance even during the hottest days of July and August. If you garden in a colder region, the Hardiness Zone Map can help you plan ahead.
Growing cannas in water also simplifies your daily garden routine. When planted in a pond or a dedicated bog area, you never have to worry about whether you remembered to water them. The water feature provides a steady supply of hydration. This makes cannas an excellent choice for busy gardeners who want maximum visual impact with a more streamlined maintenance schedule.
Choosing the Best Cannas for Water Planting
While almost any canna can be adapted to grow in moist conditions, some are better suited for life in a pond than others. Generally, gardeners categorize cannas into two main groups: terrestrial and aquatic (or water cannas). Knowing the difference can help you choose the right plant for your specific water feature.
Standard Terrestrial Cannas
Most cannas you find at garden centers or through our selection are considered terrestrial. These are the classic varieties that look stunning in garden beds and large containers. The good news is that most of these can adapt to life in shallow water quite easily. Medium Cannas are especially useful for gardeners who want a balanced size and strong garden performance.
Specialized Water Cannas
There are specific hybrid groups, such as the Longwood hybrids, that were bred specifically for aquatic life. These varieties often have slightly different leaf structures and a high tolerance for being submerged year-round in warm climates. They are excellent if you want a plant that is already "programmed" to live in a pond environment. For a smaller footprint, Short Cannas can be a smart choice.
Foliage and Flower Considerations
When selecting cannas for your water feature, think about the visual contrast you want to create. Varieties with dark burgundy or bronze foliage look striking against the blue of the water. Variegated types with striped leaves can add a bright, glowing effect to a sunny pond corner. Because cannas grow so vigorously in water, even a single rhizome can quickly become a focal point in your landscape. If you want a ready-made mix, Assorted Cannas can make planning easier.
When to Move Cannas into Your Pond
Timing is the most important factor when it is time to move your cannas into the water. Even though these plants love moisture, they are still tropical at heart. They require warm temperatures to begin active growth. Placing a dormant rhizome into cold water is one of the few ways to cause issues, as the plant needs heat to "wake up" and start processing moisture.
We recommend waiting until both the air and the water have warmed up significantly. In most parts of the United States, this means waiting until late spring or early summer. A good rule of thumb is to wait until the danger of frost has completely passed and the water temperature is consistently above 60°F. Longfield Gardens’ shipping information is also useful when you’re planning spring planting.
If you want to get a head start, you can plant your canna rhizomes in pots with soil earlier in the spring and keep them in a warm, sunny spot indoors or in a greenhouse. Once the plant has developed a few sets of leaves and the outdoor water is warm, you can then move the entire pot into your pond. This "pre-sprouting" method ensures the plant is strong enough to handle the transition to a fully aquatic environment.
Key Takeaway: Always wait for the water to warm up before submerged planting. A pre-sprouted canna with active green growth will transition to a pond much more successfully than a dormant rhizome.
Step-by-Step Guide: How to Plant Cannas in Water
Planting in water is a bit different than planting in a garden bed. You need to ensure the plant stays upright and the soil stays inside the pot. Follow these simple steps to get your aquatic cannas off to a great start.
1. Select the Right Container
Use a sturdy plastic pot with drainage holes. A five-gallon bucket or a large nursery pot works well for standard cannas, while smaller three-gallon pots are fine for dwarf varieties. Avoid using lightweight decorative pots that might float or tip over once the tall foliage catches the wind.
2. Use the Correct Soil
This is a critical step for pond health. Do not use standard potting mix. Potting mixes are usually full of peat moss, perlite, and vermiculite, all of which will float out of the pot and create a messy film on your water. Instead, use "heavy" soil. Plain garden soil with a bit of clay is ideal because it stays put and provides the weight needed to anchor the plant.
3. Planting Depth and Spacing
Place the rhizome about 2 to 3 inches below the soil surface in the pot. If you are planting multiple rhizomes in a large tub, give them a few inches of space between each other. Cannas spread via underground stems, so they will quickly fill whatever container you provide.
4. Add a Gravel Layer
Once you have filled the pot with soil and planted the rhizome, add a 1-inch layer of pea gravel or small decorative stones on top. This layer acts as a "cap" that prevents the soil from washing away and keeps fish from digging into the roots.
5. Submerging the Pot
Gently lower the pot into the water. For most cannas, the ideal depth is where the top of the pot is submerged under 1 to 4 inches of water. If your pond is deep, you can use bricks or overturned pots to create a "shelf" for the canna pot to sit on.
Action List for Planting:
- Choose a heavy, non-buoyant plastic pot.
- Use heavy garden soil or clay, never fluffy potting mix.
- Plant the rhizome 2–3 inches deep.
- Top with a layer of gravel to secure the soil.
- Submerge so the water level is just over the pot's rim.
Caring for Your Aquatic Cannas
Once your cannas are established in the water, they are relatively low-maintenance. However, because they grow so fast, they have a high demand for nutrients. Providing the right care will ensure they bloom continuously until the first frost.
Sun Requirements
Cannas are sun-loving plants. For the best flowers and the most vibrant foliage, they need at least six to eight hours of direct sunlight every day. While they can grow in partial shade, they may become "leggy" and produce fewer blooms. In a pond setting, the reflection of the sun off the water can actually help boost their growth.
Fertilizing in Water
In a traditional garden, you might sprinkle granular fertilizer on the soil. In a pond, you need to be more strategic to avoid feeding algae instead of your plants. The best way to fertilize aquatic cannas is to use aquatic fertilizer tablets. These are designed to be pushed deep into the soil of the pot, where the nutrients can reach the roots directly without leaching into the open water. Fertilize once a month during the peak growing season.
Pruning and Deadheading
To keep your water garden looking tidy, remove spent flowers. Once a flower cluster has finished blooming, cut the stalk down to the next set of leaves. This encourages the plant to put its energy into new blooms rather than seed production. You can also trim away any yellowing or damaged leaves at the base of the plant to maintain a clean look.
Managing Growth and Stability
One challenge with growing cannas in water is their impressive size. Because they have constant access to water, they can grow taller and more vigorously than they would in a dry garden bed. This can sometimes make them top-heavy.
If you find that your cannas are leaning or blowing over during summer storms, there are a few simple fixes. First, ensure the pot is heavy enough. Adding larger river rocks to the bottom of the pot before adding soil can provide extra ballast. Second, you can group several pots together. When they are clustered, they provide a bit of wind protection for each other.
For very tall varieties, you might need to use a simple stake or support ring hidden within the foliage. However, choosing dwarf varieties is often the easiest way to enjoy the look of aquatic cannas without worrying about stability. These smaller types usually reach about 2 to 3 feet in height, making them perfect for smaller basins and containers.
Dividing and Propagation
Cannas are generous plants. In a single season, one rhizome can multiply into a thick mass of roots and stems. If your cannas are growing in a pot in the pond, they will eventually become "root-bound," meaning the roots have filled the entire container.
We suggest dividing your cannas once a year, usually in the spring before you put them back in the water. Simply pull the plant out of the pot and use a clean garden knife or spade to cut the rhizome mass into smaller sections. Each section should have at least one or two "eyes" (growing points). Dividing not only gives you more plants to share or move to other areas but also keeps the original plant healthy and vigorous.
Dealing with Common Challenges
While cannas are generally easy-going, there are a few things to keep an eye on when growing them in an aquatic environment. Leading with a proactive approach makes these issues easy to manage.
Keeping Water Clear
If you notice the water in your pond becoming cloudy after adding cannas, it is likely because some soil is escaping the pot. Check that your gravel layer is thick enough. If the problem persists, you can try using a specialized aquatic planting bag or "sock" inside your pot to further contain the soil.
Canna Leaf Rollers
In some regions, small caterpillars known as leaf rollers can stitch the leaves together before they unfurl. The best approach is to keep a close eye on the new growth. If you see a leaf that looks stuck or rolled up, you can simply unroll it by hand and remove the pest. Keeping the plants healthy and well-fertilized helps them outgrow any minor insect interest.
Managing Spread
In a pond with a natural soil bottom, cannas can spread very quickly. If you want to keep them in a specific area, it is always best to grow them in pots. This "contained" method allows you to enjoy the beauty of the plant without it taking over the entire shoreline.
Overwintering Your Aquatic Cannas
Because cannas are tropical, they cannot survive freezing temperatures. If you live in a region where the water in your pond freezes, you will need to bring your cannas inside for the winter.
In Warm Climates (Zones 8-11)
In the southern United States, you may be able to leave your cannas in the pond year-round. The foliage will die back after the first frost, but the rhizomes will stay protected underwater as long as the water doesn't freeze solid. You can simply trim the dead stalks to the water line and wait for new growth in the spring. The 100% Quality Guarantee is another reason gardeners feel confident ordering from Longfield Gardens.
In Cold Climates (Zones 7 and Colder)
In cooler regions, you must lift the plants before the first hard freeze. Pull the pots out of the water and let them drain. Cut the foliage back to about 3 or 4 inches. You can then remove the rhizomes from the pots, wash off the soil, and store them in a cool, dark, frost-free place (like a basement or garage). Most gardeners store them in a box with slightly damp peat moss or sawdust to keep them from drying out completely.
The Versatility of Canna "Wet Feet"
The beauty of cannas is that they don't necessarily need a full pond to thrive in water. You can create a "bog pot" on a balcony or patio by using a decorative container without drainage holes. Fill the bottom with a few inches of gravel, add your soil and canna, and then keep the water level topped up so it sits just above the soil surface.
This method gives you the lush, water-loving look of a pond plant in a very small space. It is also a great way to use cannas as a privacy screen on a deck, as the constant water supply ensures they grow tall and thick very quickly. No matter how much space you have, there is a way to incorporate these aquatic beauties into your home garden.
Summary of Success
Growing cannas in water is a rewarding way to add a tropical feel to your landscape. By choosing the right container and soil, and waiting for the water to warm up, you can enjoy stunning blooms and dramatic foliage all season long.
- Wait for Warmth: Ensure water temperatures are above 60°F before planting.
- Use Heavy Soil: Avoid floating potting mixes; stick to garden soil topped with gravel.
- Provide Full Sun: At least six hours of direct light is necessary for the best blooms.
- Fertilize Regularly: Use aquatic tabs to feed the roots without clouding the water.
- Contain the Growth: Use pots to keep the plants from spreading too far in natural ponds.
Growing cannas in water is one of the easiest ways to create a high-impact garden feature. With just a little bit of preparation in the spring, these plants will reward you with a summer full of color and life.
Whether you are a seasoned pond owner or just starting your first water garden, we at Longfield Gardens are here to support you. Our 100% quality guarantee ensures that your rhizomes arrive in prime condition, ready to transform your garden. If you have questions about your plants' performance during their first growing season, our team is always ready to help. Happy planting!
FAQ
Can I put a regular canna from my garden bed directly into a pond?
Yes, most standard cannas can transition to water. It is best to wash the garden soil off the roots and replant it in a pot with heavy clay soil and a gravel cap to keep your pond water clean. If you want more general planting tips, the FAQs - Spring Planted Bulbs page is a helpful resource.
How deep should I submerge my canna pot?
Most cannas prefer to have the top of their pot submerged under 1 to 4 inches of water. While they love "wet feet," they generally do not want to be buried deep underwater where the stems cannot reach the surface easily.
Will cannas grow in a pond without soil?
While cannas can survive for a short time in plain water (like in a vase), they need the nutrients and stability found in soil to bloom and grow to their full size. Planting them in a pot with heavy soil and gravel is the best method for long-term success.
Do aquatic cannas attract mosquitoes?
Cannas themselves do not attract mosquitoes, but standing water can. If you grow cannas in a pond or water feature, ensure the water is moving with a pump or fountain, or use "mosquito dunks" to keep the water safe and clear of larvae.