Winterizing Water Lilies in Cold Zones: Hardy & Tropical Care

Seeing your beautiful water lilies thrive in the summer is a joy, but the thought of a harsh winter can be worrying for any pond enthusiast. You’ve put so much care into them, and you want to see them again next year. The good news is that with a few simple steps for winterizing water lilies in cold zones, you can protect both your hardy and tropical varieties from the cold and ensure they return with vibrant blooms next spring.

The Quick Answer

To winterize water lilies in cold zones, move hardy varieties to the deepest part of your pond where the water won’t freeze solid. For tropical water lilies, you’ll need to bring them indoors. You can either store the dormant tubers in a cool, dark place or keep the entire plant actively growing in an aquarium with a grow light until spring.

First Things First: Do You Have a Hardy or Tropical Water Lily?

Before you can begin the process of winter care, you must identify what type of water lily you have. Understanding the difference is the most critical first step, as their winter care needs are completely different. Getting this wrong is the number one reason gardeners lose their beloved plants over the winter. At theplatformgarden.com, we’ve seen this happen, and we want to help you avoid it.

Hardy water lilies are built for cooler climates, while tropical water lilies, as their name suggests, are native to warmer regions and cannot survive freezing temperatures.

Here’s how you can tell them apart:

• The Leaves: This is often the easiest way to distinguish them. Hardy water lily leaves (or lily pads) have smooth, rounded edges and typically float flat on the water’s surface. Tropical water lilies often have wavy, ruffled, or serrated edges. Some tropical varieties even have vibrant, mottled patterns on their pads.
• The Flowers: Hardy lily flowers are beautiful but tend to be more subdued. They float directly on or just above the water’s surface. Tropical lily flowers are true show-stoppers. They are held high above the water on strong stems and often come in more exotic colors, including vibrant blues and purples, which are not found in hardy varieties. Tropicals are also frequently fragrant.
• Blooming Time: Tropical water lilies often bloom more profusely and later into the season than their hardy cousins. Many are also night-bloomers, opening their blossoms in the late afternoon and closing them the next morning.

If you’re still unsure, think back to where you purchased it. Most sellers, like those offering hardy water lilies for sale, will clearly label the type. Knowing your specific variety is key to successful water lily winter care.

What You’ll Need: Your Winterizing Toolkit

Having the right supplies on hand before you start will make this process quick, easy, and efficient. You don’t need a lot of fancy equipment, but the right tools will protect both you and your plants. Here’s a checklist of what you might need, depending on your lily type and chosen method:

• Pond Scissors or Pruners: For trimming away dead or dying leaves and stems. A long-handled pair can be a back-saver!
• Aquatic Gloves: A pair of waterproof, elbow-length gloves will keep your hands warm and dry while you work in the cold pond water.
• A Large Bucket or Tub: Essential for transporting your lilies or for washing soil off the roots of tropical varieties.
• Peat Moss, Sphagnum Moss, or Sand: This is the storage medium for dormant tropical water lily tubers. It helps maintain the right moisture level to prevent them from drying out or rotting.
• Fungicide Powder (optional but recommended): A light dusting of fungicide can prevent rot and fungal diseases on stored tropical tubers during their long winter dormancy.
• A Plastic Bag or Glass Jar: To store your tropical tubers in the peat moss or sand.
• An Aquarium or Large Watertight Container: This is necessary if you plan on keeping your tropical water lily actively growing indoors. A 10-20 gallon aquarium works well for most smaller plants.
• A Grow Light: If you’re keeping a tropical lily growing indoors, you’ll need a full-spectrum grow light to provide the necessary light for photosynthesis. A simple clip-on model can suffice.
• A Pond Heater or Bubbler (optional): For those with shallow ponds in very cold climates (like USDA Zones 3-4), a small pond heater or a bubbler can keep a hole open in the ice, which helps with gas exchange and can prevent the pond from freezing solid.

How to Winterize Hardy Water Lilies: The Simple Method

Protecting your hardy water lilies is surprisingly easy. Since these hardy water plants are adapted to colder climates, they just need a little help to avoid the harshest freezing temperatures at the surface. Their rhizomes are tough, but they can’t survive being encased in solid ice.

The goal is simple: get the plant’s growing crown (the rhizome) below the frost line in your pond.

Step 1: Wait for the First Frost
Don’t be too eager to start. Wait until after the first light frost has yellowed the leaves. This signals to the plant that it’s time to go dormant. Trimming too early can disrupt its natural cycle.

Step 2: Trim the Foliage
Using your pruners or scissors, cut back all the yellowing leaves and stems to about 2-3 inches from the base of the plant. Removing this decaying organic matter is crucial for maintaining good water quality in your fish pond over the winter.

Step 3: Relocate to the Deep
This is the most important step in how to winterize hardy water lilies. The rhizome needs to be in a part of the pond that will not freeze solid. For most cold climates, a depth of 18-24 inches is sufficient. If your lily is in a planting basket, simply lift it and gently place it in the deepest part of your pond.

What if My Pond is Shallow?
If your pond is less than 18 inches deep, it risks freezing solid, which will kill the lily. In this case, you have two options for overwintering water lilies in pots:

1. Lift and Store: Lift the potted lily out of the pond after trimming it back. Place the entire pot in a large plastic bag, add a bit of water to keep it moist, and seal it loosely. Store it in a cold, dark place that stays above freezing but below 50°F (10°C), like an unheated basement or garage.
2. Use a Pond Heater: A small de-icer or bubbler can keep a small area of the pond from freezing solid, which might be enough to protect the rhizome in a borderline climate.

In the spring, once the danger of hard frost has passed, you can lift the pot back to its sunny summer shelf in the pond.

How to Winterize Tropical Water Lilies: Two Great Options

Tropical water lilies are the drama queens of the pond world, and their winter care requires a bit more effort. Because they cannot survive water temperatures below 50°F (10°C), winterizing water lilies in cold climates means you must bring them indoors. You have two main choices: let them go dormant or keep them growing.

Option 1: Storing Dormant Tubers

This is the most common and space-saving method for overwintering water lilies. It involves encouraging the plant to create a dormant storage organ, called a tuber, which you can then store until spring.

Step 1: Lift the Plant After the First Frost
Just like with hardy lilies, wait for a light frost to signal the plant. Then, lift the entire pot out of the pond. The foliage will likely look limp and blackened—this is normal.

Step 2: Wash and Find the Tuber(s)
Place the plant in a tub or on a tarp and gently wash the soil away from the roots with a hose. You are looking for a small, firm tuber that looks like a black acorn or a small potato. A mature plant may have formed several. This is the part of the plant that will grow into a new lily next year.

Step 3: Clean and Cure the Tuber
Gently trim away all the old roots and leaves from the tuber. Rinse it clean and let it dry in a shaded, airy spot for a day or two. This “curing” step helps prevent rot.

Step 4: Treat and Store
For extra protection, you can lightly dust the dry tuber with a fungicide powder. Then, place the tuber in a small, sealed plastic bag or glass jar filled with slightly damp peat moss or clean sand. The goal is to keep it from drying out completely but not to keep it wet, which would cause it to rot.

Step 5: Keep it Cool and Dark
The ideal storage temperature for storing tropical water lily tubers is between 50-55°F (10-13°C). A cool, unheated basement or insulated garage is perfect. Check on the tuber once a month to ensure the sand or moss is still slightly damp.

Option 2: Keeping Them Growing Indoors

If you have the space and want to enjoy your tropical water lily all winter, you can bring it inside and keep it as an aquatic houseplant. This method of keeping water lilies indoors over winter can even result in occasional blooms!

Step 1: Prepare the Plant
Before the first frost, lift the pot from your pond. Trim away most of the larger, older leaves and any flower stems, leaving the small, new growth in the center. This reduces the plant’s size and energy needs.

Step 2: Set Up an Aquarium
Place the trimmed plant, still in its pot, into a large watertight container like a 10-20 gallon aquarium. Fill the aquarium with enough water to cover the top of the pot by at least 6 inches. Using dechlorinated water is best.

Step 3: Provide Light and Warmth
This is the key to success. Place the aquarium near a sunny window, but you will almost certainly need to supplement with a full-spectrum grow light for 10-12 hours per day. The water temperature should be kept consistently around 70°F (21°C).

With this method, your tropical lily won’t go into dormancy. It will continue to produce new leaves throughout the winter. Do not fertilize it during this time; you just want to keep it alive, not encourage vigorous growth until it’s ready to go back outside in the spring.

3 Common Mistakes to Avoid When Winterizing Water Lilies

Even with the best intentions, a few simple mistakes can spell trouble for your lilies. Here at theplatformgarden.com, we want to help you avoid the most common pitfalls we see.

1. Leaving Hardy Lilies in a Shallow Pond that Freezes Solid. This is the number one killer of hardy water lilies. People assume “hardy” means indestructible, but if the rhizome itself freezes solid, it will turn to mush and die. Always ensure it’s deep enough or bring it inside.
2. Storing Tropical Tubers When They Are Still Wet. This is a guaranteed recipe for rot. After washing the tubers, they must be allowed to air dry for a day or two before being packed in damp sand or moss. The storage medium should be barely moist, like a wrung-out sponge, not wet.
3. Forgetting to Fertilize in the Spring to Wake Them Up. When you return your lilies to the pond in the spring, they are waking up from a long slumber and are very hungry! Giving them a good dose of aquatic plant fertilizer will provide the energy they need for strong spring regrowth and a season full of beautiful lily pads and flowers.

Frequently Asked Questions (FAQ)

Do water lilies come back every year?

Yes, if you give them the right winter care for their type, both hardy and tropical water lilies can be grown as perennials and will come back every year. Proper winterizing of water lilies in cold zones is the key to ensuring their return. Hardy lilies will reliably return in zones they are rated for, while tropicals depend entirely on you to save them from the cold.

Should I cut back my water lilies in the winter?

Yes, you should trim away any yellowing or dead leaves and stems before moving your water lilies for their winter rest. This is an important step in both winter care for hardy water lilies and winter care for tropical water lilies. It helps prevent the decaying plant matter from fouling the water in your pond or your indoor storage container.

What temperature is too cold for water lilies?

This is a critical question. Hardy water lilies can survive as long as their rhizomes are below the ice line in the pond and are not frozen solid. The water around them can be near freezing. Tropical water lilies, however, are much more sensitive. They will be damaged or killed if their tubers are exposed to water temperatures below 50°F (10°C) for an extended period.

With a little bit of fall preparation, you can ensure that your water lilies, whether hardy or tropical, will survive the cold winter and return to grace your pond with their beautiful blooms next year. It’s a simple process that protects your investment and rewards you with another season of stunning aquatic beauty. By choosing the right method for your specific type of lily, you’re setting yourself up for success in winterizing water lilies in cold zones.

What is your biggest challenge when it comes to overwintering pond plants? Share your experiences or ask any questions in the comments below! For more tips on creating a thriving water garden, check out our complete guide to Choosing the Best Koi Pond Plants.