Water Gardens: Everything You Need to Know

Water garden featuring stones and aquatic plants

It’s easy to think water gardens are reserved for professional gardeners. Growing plants in the soil can be hard, but growing them in the water? You’d rather admire the neighbor’s aquatic landscape feature from afar than get your feet wet tending to the garden. 

With rippling waterfalls, swinging cattails, and floating water lilies, a landscape feature so extraordinary must be impossible to install and maintain in your own yard, right? Not necessarily. Even beginner gardeners can nurture a water garden and enjoy its soothing sounds and wildlife after a stressful day. 

From porch containers to in-ground reservoirs, you can grow a water garden in many shapes and sizes. But what is a water garden exactly? How can you possibly garden in the water? We’ll answer these landscaping questions, and more, in our water garden guide below. 

What is a water garden?

Water gardens, also known as aquatic gardens, are water features that display various aquatic plants. These gardens also can act as fish ponds or garden ponds, but it’s primarily the aquatic plants that make it a water garden. 

Whether grown in a container, shell liner, PVC liner, or indoors, water gardens can be any shape or size and show off many different designs. Although deep ones can exist, most water gardens are shallow, as many aquatic plants are sensitive to depth. 

Your water garden may be a water source for small animals, including birds and squirrels. You may even spot the occasional frog or salamander. 

What plants are in a water garden?

Expect to grow most of your aquatic plants in shallow containers that you’ll submerge into the water. 

Before submerging your plants, know the exact water level each plant can survive in. Some plants can only be immersed in a few inches of water and die if the crown is too far below the water surface. Remember, water plants are depth sensitive. 

Some plants may be too large for your underwater containers. Large barrels are an easy substitute for these bigger plants. 

Floating plants

Single water lily floating on water surrounded by lily pads
Photo Credit: Sirpa P / Pixabay 

These plants float at the top of the water surface. Their roots are anchored at the water garden’s bottom, while their leaves and flowers float above the water. Some floating plants are free-floating, meaning the entire plant is suspended on the water and can move freely over the water surface. 

Floating plants help provide shade, keep the water clean, and control algae. 

Algae love warm temperatures, and it needs the sun to perform photosynthesis. Floating plants help lower water temperatures and limit the algae photosynthesis process by blocking sunlight. 

Floating plants include: 

  • Duckweed
  • Water lettuce
  • Water lilies
  • Lotuses
  • Water hyacinth
  • Spatterdock

Oxygenating plants

Also known as submerged plants, oxygenating plants grow at the water garden’s bottom, immersed below the water surface. These plants filter the water, keep algae growth under control, provide oxygen, and offer small fish shelter. 

Oxygenating plants include: 

  • Hornwort
  • Eelgrass
  • Anacharis
  • Cabomba

Marginal plants

Pickerel weed growing in one large mass
Photo Credit: Robbie Sproule / CC BY 2.0

Also called shelf plants, marginal plants are depth sensitive and best grown near the water garden’s edge or margin. Unlike floating plants or oxygenating plants, they cannot grow at deep levels.

These aquatic plants live best when the water is only a few inches above the plant’s crown, around 6 inches. However, the depth will vary among plant types. 

Usually, a water garden will have a shallow shelf along its edge where these marginal plants can grow. If you need to adjust or add shelf levels in your water garden, use stackable crates to establish various shelf heights within the water. 

Marginal plants provide filtration, help suppress algae growth, and attract wildlife to your water garden. 

Marginal plants include:

  • Cattails
  • Arrowhead
  • Pickerelweed
  • Water plantain
  • Sweet flag

Bog plants

Purple pitcher plant growing in grassy bog area
Photo Credit: Aaron Carlson / CC BY-SA 2.0

Bog plants are often used interchangeably with marginal plants, but there are some differences between the two.

Marginal plants grow well with parts of the crown underwater, while bog plants prefer wet soil above water level. Bog plants, common in bog gardens, typically grow best just on the water garden’s exterior, where the ground remains moist but isn’t soaking wet. 

Bog plants include: 

  • Water iris
  • Rose pogonia
  • Ladies tresses
  • Pitcher plants

How to Build a Water Garden

If you’ve got the DIY skills, the yard space, and the time, installing an in-ground water garden makes an excellent weekend project. 

Choose your water garden’s location wisely. Water gardens offer a great source of relaxation. Don’t let its charm and soothing sounds go to waste by installing it somewhere with an obstructed view. Install your water garden near your favorite window, right by the deck, or in your calming flower patch. 

Water gardens benefit from the sun. Make sure your aquatic plants get full sun and are not in too much shade. 

Menards offers step-by-step video instructions on installing the outdoor pond shell liner and water pump for your water garden. Lowe’s also provides image instructions on how to build a water garden. 

Let’s start with what you’ll need to build your water garden (besides your water garden plants, of course):

Containers

Water gardens needn’t be large. You can grow one in a small container for your container garden, flower beds, or patio. 

Check out how The Home Depot builds a small water garden with a pump, bricks, gravel, container, and aquatic plants in this instructional video

Pumps

A pump ensures your water garden has a healthy ecosystem. Pumps evenly distribute nutrients and oxygen to plants and other aquatic life in your water garden. 

Pumps also help to prevent algae and stagnation. Stagnant water can be a breeding ground for mosquitoes.  

Water features

Water features such as fountains, bubblers, and waterfalls, can turn your water garden into an oasis. Sit back and listen to the mesmerizing sounds of trickling water as you gaze upon the nature around your water garden. 

Water features are also another way to encourage moving water and aeration in your water garden. The moving water helps to add oxygen to the ecosystem and prevent stagnation. 

Fish

It’s possible to add pond fish to your water garden. They’re beautiful to look at and can be rewarding to care for. Keep in mind that fish will likely increase the water garden’s maintenance requirements, making it similar to a goldfish pond or garden pond. 

Pro Tip: If you want to turn your water garden into a koi pond, koi fish require a specialized habitat and filtration system. Their habitat’s ecosystem will look much different compared to a water garden without any fish. 

How to Maintain a Water Garden

Skipping out on water garden maintenance can get ugly fast. Ignore your water garden’s needs for too long, and you could be dealing with a smelly, dirty environment that now demands even more care. 

For a healthy and balanced ecosystem, it’s best to perform routine maintenance on your water garden. 

Keep in mind that maintenance will vary depending on your water garden’s design and features. A small container water garden won’t need as much care as a water garden pond. 

Below, we’ve listed the most basic, low-maintenance water garden needs. A water garden that’s a koi pond will require more complex maintenance needs beyond these basics. 

Manage debris

Leaves, grass clippings, and other debris from the yard are bound to make their way to your water garden. Keep the skimmer net close by so you can collect and remove waste from your water garden. 

Encourage plant growth

If your water garden is looking low on plants (perhaps a few have died), add some more. Plants are essential for the health of your water garden as they help keep the water clean, add oxygen, and compete with algae. 

Remove dead plants

Dead plants can release toxins into the water garden and contaminate the environment. As soon as you spot dead plants, remove them from the water. 

Add fertilizer (the right kind) as needed

Fertilizing your aquatic plants will depend on the quality of your garden’s water. If your plants appear to be in good health and the water quality is fine, you may not need to fertilize your water garden. 

Now don’t go throwing in regular soil fertilizer. The same fertilizer that nourishes your vegetable garden and flower beds can do significant damage to the aquatic life in your water garden. You may even wind up with an explosion of algae. 

Only use specialized fertilizers for aquatic plants or water gardens. 

Winterize your water garden

Some aquatic plants may not survive the threat of frost. Check your U.S. Department of Agriculture (USDA) plant hardiness zone and your plant’s hardiness level to determine the best winterization method for specific plants. You may need to remove some plants from the water and store them in a protected barrel or bucket in a non-freezing area. 

Remove any pumps or tubing that you don’t plan to use during the winter. 

You’ll want to limit ice in your water garden. Ice can kill the water garden’s aquatic life by preventing oxygen from entering the water and trapping in harmful gasses. 

Prevent freezing by using a pond de-icer. Heaters can also help to prevent ice. 

Remember, never break a water garden’s icy surface, as this can harm aquatic life. It’s best to melt the ice instead. 

Check for leaks

Inspect your water garden for leaks. If the water level has lowered or the surrounding ground is unexpectedly wet, your water garden may have a leak that needs correcting. 

FAQ about Water Gardens

Will my water garden attract mosquitoes?

A poorly maintained water garden is a hot spot for mosquitoes. The best way to keep mosquitoes under control is prevention. Here are three ways to ensure your water garden is well maintained to help keep at bay mosquitoes and mosquito larvae. 

  • Limit algae growth. Mosquito larvae love to feed on this food. If your water garden is swimming with algae, mosquitoes will find it very attractive. 
  • Keep the water moving. Mosquitoes lay their eggs in stagnant water. Increase flowing water with pumps, water fountains, or waterfalls. 
  • Add fish to your water garden. If mosquitoes are a big problem or concern, some fish will eat these pesky bugs for you. 

If prevention methods don’t keep these mosquitoes away from your water garden, consider calling a pest control professional

Why are algae harmful to my water garden?

Too many algae can lower the oxygen levels in your water garden and block sunlight from reaching your aquatic life. When the algae die, the microbes that decompose the dead algae will consume even more of the garden’s oxygen. 

Low oxygen levels will begin to kill your water garden’s fish and plants. Once the algae bloom has become so severe and aquatic life can no longer survive, your water garden will become a dead zone. 

Are some water garden plants invasive?

Some aquatic plants are invasive and need to be maintained, among these are alligator weed, giant reed, hydrilla, water lettuce, and water chestnut. 

When to Call a Professional Landscaper

Building a water garden may be easy for some, but not everyone wants to get his or her hands dirty. And sometimes we’d rather avoid costly mistakes. 

Call a local landscape professional near you for assistance with water garden installation or design. A professional can ensure your water garden is in good condition and fits into the landscape. 

Water Gardens are Relaxing — and Fairly Easy to Build and Grow

Don’t get your relaxation and zen time by drooling over the water garden across the street. Grow an oasis in your own yard, and relish the sounds of running water, jumping frogs, and splashing waterfalls. Hang a few windchimes, listen to the rustling cattails, and let your worries wash away. 

Whether you’re a first-time gardener or a master green thumb, you can grow a water garden in your yard (and one better than the neighbor’s).

Main Photo Credit: Nowis / CC BY-SA 3.0

Jane Purnell

Jane Purnell

Jane Purnell is a freelance writer and actor in New York City. She earned her B.A. from the University of Virginia and enjoys a warm cup of French press coffee.