Before diving into the best plants for koi pond, let’s briefly explore the conditions koi need to thrive under your care. This way, we can have a better understanding of how aquatic plants facilitate the required conditions for koi ponds.

Owning a koi pond is a unique and rewarding experience, giving you the pride of creating your own living ecosystem in your backyard.

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An important part of this ecosystem are koi pond plants, which can improve the look of your water garden and the health of your koi fish.

Maintain Optimum Water Quality 

In order to ensure good health and comfort for your koi fish, it is important to maintain optimal water conditions in the pond. Poor water quality can lead to health problems for your koi, so it is essential to periodically test the water.

Keep Water at Ideal Temperature for Koi 

Water temperature is a crucial factor that directly affects the health of koi, as well as impacts the metabolic rates of all other living organisms in your pond.

Although koi are cold water fish, they can live in a wide range of temperatures since their body temperature adapts to the surrounding water. 

Koi survive for shorter periods at higher temperatures because warm water cannot hold much oxygen. Similarly, cold or freezing water will diminish the koi immune system.

The temperature of the pond should be adjusted gradually in order to protect the health of koi. For example, shade the pond using water gardening plants or koi pond accessories to help slowly cool down the water temperature. 

It is also important to note that the fluctuation in outdoor temperatures will more rapidly affect a smaller pond’s ecosystem. Constructing a more spacious pond or including aquatic plants will help keep the environment suitable and stable for koi fish. 

Choose the Correct Water Filtration System

a woman installing a water filtration system

Source: Amazon

To purify pond water from waste, debris, or any other toxins, it is important to choose the correct pond filters.

If you are unsure about selecting the right filter for your koi fish pond, ask a local garden supply store to help you find the appropriate high quality pond filter. 

Prevent Pond Overcrowding

Koi fish require ample space to grow to their fullest and healthiest. Aim to create a spacious garden pond, while limiting the number of koi fish.

Overcrowded koi may develop problems such as producing an excess of waste containing ammonia, depletion of dissolved oxygen, and an increase in algae.

Koi Pond Plants

Now that we know the conditions koi fish require to maintain a healthy lifestyle, let’s see how aquatic plants for koi ponds can combat some common issues and assist in providing koi with the optimal environment.

Koi owners must carefully select the plants included in the koi water garden ecosystem, to ensure all members are synchronized and not inflicting any harm to the other living beings in the pond environment. 

Benefits of Aquatic Plants

Aquatic plants in a koi pond

Aquatic plants play an important role in the life of a koi pond. They can assist the production of oxygen in water and also help maintain proper aeration for the koi fish.

Their physical placement in the pond can also lower the temperature of the pond water while providing koi with a shaded area. Koi pond plants also assist in keeping water cleaner by limiting the growth and preventing the spread of algae.

The plants provide shade, which reduces the amount of light the reaches the pond and keeps the water temperature low. Both the limited sunlight and cooler water temperatures restrict the production of algae.

Aquatic plants also absorb nitrates in the water that can be harmful to koi and aid in the development of algae. If you are looking to allow your koi fish to breed, aquatic plants are necessary to facilitate this process, as female koi fish lay their fertilized eggs on the plants.

Best Plants For Koi Pond

Garden supply stores offer a variety of koi pond plants for sale. The best method is to choose an array of various plants. The three most popular categories of pond plants used in koi water gardens are:

  • Floating plants
  • Shallow water marsh plants
  • Submerged plants

best koi pond plants

Ideally, you should have a mix of all three types of these plants in your water garden. A blend of these plants will provide the highest cover and versatility, while also welcoming diversity into your koi pond. Whatever plants you decide to include in your ecosystem, make sure that you are knowledgeable on their habits and needs.

Plants selected should be well suited to the climate – not all plants thrive in hot and sunny conditions, and some flora grow too fast for smaller ponds.

Additionally, your koi fish will probably pick at the plants within the water. You should be wary of plants that are too fragile or that grow too slowly, as they can be eaten to death by your hungry fish.

If you decide to move forward with slow growing plants to save on maintenance, you can limit koi inflicted damage by regularly feeding them greens like lettuce and cabbage.

You should also protect the roots of your aquatic plants by covering them with koi pond accessories or keeping them out of reach of your koi fish.

On the other hand, plants that are tough and that grow quickly can easily overpower smaller ponds. It is important to find balance between the aquatic plants and koi in your water garden.

Popular Categories of Pond Plants

Floating Plants

Water lilies are the most popular aquatic plant for koi pond owners

This type of pond plant is unique as it is able to float freely with the main vegetation resting on the surface of the water with its roots hanging unattached below.

There are also floating plants whose roots attach to the muddy bottoms of the pond. The greatest benefits of floating plants are that they are lower maintenance and easier to care for. They provide ample shade for the koi fish.

They compete with algae for nutrients, and they reduce sunlight, which limits the growth of algae, and they also eliminate nitrogen and phosphates that exists in the water, which makes for a great natural filtration system. 

The most popular types of floating plants are featured below:

  • Water Lotus – Lotus are among the oldest cultivated aquatic plants. They are characterized by beautiful large leaves, which can grow to up to 18-inches across, and a lovely fragrant scent. 

    Lotus flowers are best suited for larger koi ponds, as they have considerable growth rates. If you have the room for them, water lotus provide an ample amount of shade for koi fish during the warmer months.

  • Water Lettuce – This popular plant is better suited for a warm and tropical climate. Water lettuce feature leaf clusters above the surface, and compact root structures under the plant.
  • Water Hyacinth – The water hyacinth is an annual in colder areas of North America and a perennial in warmer regions. 

    They grow blue or purple flowers, and its roots form a compacted nest beneath them. These plants are excellent at filtering out excess nutrients.  

  • Water Lily – Water lilies are the most popular aquatic plant for koi pond owners. They are diverse and can thrive in nearly any region of North American in any season. 

    These plants can even be potted and placed at the bottom of ponds. Water lilies have pretty flowers and leafy coverage on the surface, and attached roots below the surface. 

  • Water Poppy – This aquatic plant has small oval-shaped leaves with yellow flowers. Water poppies grow fast in the summer, and provide a yellow accent to water gardens. They also provide a great filtration system for ponds.
  • Fairy Fern – Fairy moss is ideal for koi ponds of any size. They can grow into thick clusters that block out light, which reduces algae growth and provides a cooler habitat for the koi. 

    In areas that are warm year-round, fairy fern can even grow to be so thick that it may create a barrier where mosquitoes would not lay eggs.

Shallow Water Marsh Plants

Water Iris in a koi pond

For a more natural look for your water garden, consider shallow water marsh plants. These types of plants are able to be plated partially submerged in the shallow marsh water located at the edge of your pond. 

The most popular types of these plants for koi ponds are:

  • Water Iris – A koi pond favorite, the water iris has several to choose from. They survive in partial or full sunlight, so they are a great option for water gardens with tree coverage.
  • These plants have a long and sharp leaves, and depending on the species, the flower colors can be white, blue, or yellow. Most commonly, water irises are potted and then submerged in water. 
  • Umbrella Plants – These tropical plants do well in shallow water. However, if you live in a colder region, umbrella plants should be kept inside throughout the winter months.
  • They are characterized by leaves with an umbrella shape at the end of long stalks.
  • Horsetail – These aquatic plants are best planted on the edges of the pond. They thrive the most in partial shade. Horsetail creates thin green stems and grows quickly.

Submerged Plants

The most common for koi ponds is the Red Ludwigia

Source: Amazon

Submerged plants are the oxygenating plants that are mentioned above, and they assist koi fish by filtering out excess nutrients such as nitrites and carbon dioxide, and of course, adding oxygen to the water.

They require extensive care to make sure they are protected, as koi fish tend to uproot and nibble on these plants. 

These plants are typically planted and grown within pots that are placed on the floor of the water garden.

  • Fanwort – This plant grows quickly, and can even grow up to one inch each day, though it requires a large amount of sunlight. Fanwort can be proliferated using cuttings. 
  • Water Purslane – While there are many species of this plant, the most common for koi ponds is the Red Ludwigia. Its red or purple leaves produce small flowers, are requires direct sunlight. 

    This species is versatile as it can be used as a submerged plant or a floating plant. It is fast-growing and oxygenates the water. 

  • American Waterweed – The American Waterweed is best housed in sandy pond layers in milder climates. These plants are full submerged, though a small, white flower blossoms above the surface of the water. 

    They are great at oxygenating the water and sheltering koi.

How to Install Koi Pond Plants

One way to insert plants into your koi water garden is with a plant shelf, which is typically installed at the edge of a pond. Plants are planted and grown on the shelf beneath the surface of the water, about 10 to 18 inches.

On the shelf, aquatic flora should be planted in an underwater planter lined with large rocks or stones to weigh it down and to create a barrier between the plant and koi, to protect the integrity of the plant.

However, beware that plant shelves are commonly used by animal predators to feed on the koi.

Wrapping Up Best Plants For Koi Pond

Pond plants can also be placed directly into the pond, though it can make the plant maintenance a little more difficult.

If you already have a pond in your garden or enough free space to make one, better start now and you’ll surely enjoy spending more time in your garden. 

There are a lot of benefits in having pond plants. Now that you know the best plants for koi pond, all you need to do now is take your pick and have fun with your koi pond!