15 Best Plants to Grow in a Koi Pond

Plants in a koi pond with fish swimming — It can be hard to find plants that can withstand kois' hungry appetites.

While aquatic plants can add a lot of visual interest to ponds, if you keep koi, you may want to look for koi-proof plants that can withstand the attention of your hungry fish! Some plants are naturally less attractive to koi, while other plants grow so quickly that it doesn’t matter if koi eat them or not. Below, we’ve listed some of the most resilient plants to keep in fish ponds, and we’ve also added planting tips to inspire your next pond design.

1. Water lilies (Nymphaea spp.)

A pink flowered water lily — Water lilies provide shade for koi and perching places for dragonflies and frogs.

Plant name:	Water lilies
Light requirements:	Full sun to part shade
Growing zone:	Zones 4 to 11, depending on a variety
Maximum planting depth in water:	18 to 24” deep

Water lilies can be found throughout the globe, and some water lily species are even native to North America. Most water lily plants feature heart-shaped pads, which provide shelter for koi fish and make a perfect perching spot for dragonflies and frogs too! But while water lily pads have their appeal, most growers keep water lilies for their showy blooms, which come in shades of pink, red, yellow, orange, purple, blue, and white.

Water lilies typically bloom from May through September, and each delicate flower lasts for about 4 days before it sinks back into the watery depths. Curious koi may sometimes munch on water lily roots, but they also use lily leaves as a shelter for their developing eggs. For best results, water lilies should be grown in full sun to part shade, and you can use pots or planting bags to anchor these plants into your pond if needed.

2. American water lotus (Nelumbo lutea)

Yellow flowered American lotus — The American lotus has a waxy coating that helps it resist environmental stressors.

Plant name:	American water lotus
Light requirements:	Full sun
Growing zone:	Zones 4 to 11
Maximum planting depth in water:	3’ deep

Exotic and breathtaking American water lotuses are famed for their yellow, bowl-shaped blooms that appear from mid-to-late summer. But while these plants are mostly prized for their flowers, water lotus plants also boast big, round, vibrant green pads. Interestingly, those pads are covered in a waxy coating, which helps the plant resist environmental stressors.

Native to central and eastern North America, American water lotus can grow aggressively in some areas, so you may need to occasionally prune out sections of these plants to keep them from spreading. Ideal for larger ponds that are at least 3’ deep, American water lotus leaves can stretch over 2’ in width, so they may be too massive for small koi setups. Koi may nibble on water lotus plants, but these plants tend to be less attractive to koi than some other water plants, such as watercress and duckweed.

3. Water lettuce (Pistia stratiotes)

Floating water lettuce plants — Water lotus is a good beginner-friendly aquatic plant that works well in koi ponds.

Plant name:	Water lettuce
Light requirements:	Full sun to part shade
Growing zone:	Zones 9 to 11
Maximum planting depth in water:	Floating plant

Water lettuce can be a great plant to try in koi ponds if you’re new to keeping aquatic plants. These beginner-friendly specimens float right on top of the water’s surface, and they will help to shelter koi and other pond inhabitants from aerial predators like herons. However, water lettuce plants can be invasive in some areas, so they should only be grown in enclosed pond environments where they can’t spread.

Many pond centers carry water lettuce plants, so you shouldn’t have any trouble tracking some down. Once you add water lettuce to your pond, these plants will generally reproduce quickly, and they’ll provide you with many more plants for your water garden. Koi will eat water lettuce plants from time to time, but that’s usually not a problem because these plants grow so quickly.

4. Water iris (Iris spp.)

Purple flowering water irises — Water iris provides vibrant color with its pretty purple blooms.

Plant name:	Water iris
Light requirements:	Full sun; varieties with light-colored flowers may benefit from some afternoon shade
Growing zone:	Zones 5 to 9
Maximum planting depth in water:	3 to 6” deep, depending on a variety

Water irises are certainly attractive plants, but they’re also incredibly resilient. These beauties typically bloom from May to July, and their flowers come in a rainbow of colors, including purple, blue, red, lavender, and yellow. Most water iris plants will grow best in full sun, although plants with white or yellow flowers may benefit from afternoon shade, which will shelter their delicate petals from the summer heat.

Most of the time, water irises are grown as marginal plants around the exterior of pond settings, but these plants prefer to have their roots submerged in a bit of water. How much water irises can be grown in will depend on the particular species, but most water irises prefer to have their crowns covered with about 3 to 6” of water. In koi ponds, water irises can be very low maintenance, and even better, koi fish generally won’t eat them!

5. Water poppy (Hydrocleys nymphoides)

Yellow water poppy flowers — Water poppies prefer to grow in shallow water or pots.

Plant name:	Water poppy
Light requirements:	Full sun to part shade
Growing zone:	Zones 9 to 11
Maximum planting depth in water:	12 to 15” deep

Another solid choice for beginning pond keepers, water poppies are quite easy to grow as long as you provide them with the right growing conditions. Water poppies can either be planted directly in pond soil, or they can be kept in planting pots or pond baskets. These plants can be grown in water that’s up to 15” deep, but they prefer to grow in shallower conditions if possible.

Water poppies’ bright green, rounded leaves will provide shelter and shade for koi and other pond critters, but these plants are mostly kept for their highly ornamental, yellow flowers. When properly maintained, water poppies will grow rapidly, and they may take over your pond if you don’t prune them regularly. In fact, water poppies are considered to be invasive in some areas, so you’ll want to keep them in an enclosed pond system so they don’t spread.

6. Dwarf Egyptian papyrus (Cyperus prolifer)

Dwarf Egyption papyrus — Papyrus pith was once used to make paper in ancient Egypt.

Plant name:	Dwarf Egyptian papyrus
Light requirements:	Full sun to part shade
Growing zone:	Zones 8 to 10
Maximum planting depth in water:	1 to 4” deep

Papyrus plants have a rich history, and the pith of papyrus plants was once used like paper by the ancient Egyptians. Today, papyrus plants are mostly kept as ornamentals and smaller varieties can even be grown as houseplants! Some papyrus plants are massive, and they can stretch up to 16’ tall; however, dwarf Egyptian papyrus is much more manageable in small koi ponds, and it only grows to about 1’ in height.

While you can grow papyrus plants on their own, they look more impressive when several plants are grown together in a large clump. For best results, locate dwarf Egyptian papyrus plants on the perimeter of pondscapes and make sure the plant’s roots are covered by about 2 to 6” of water. When mature, papyrus plants will add an elegant feel and a strong silhouette to your koi pond, and they also move beautifully when the wind blows!

7. Taro (Colocasia esculenta)

Elephant ears in a pond planting — Popular in garden beds, elephant ears can also be grown on pond perimeters.

Plant name:	Taro
Light requirements:	Part shade
Growing zone:	Zones 9 to 11
Maximum planting depth in water:	2” deep

Taro or elephant ears are commonly kept as ornamentals in gardens, but these water-loving plants can also be grown in shallow water around the perimeter of koi ponds. With their oversized, heart-shaped leaves and tropical feel, taro plants make a big impact in pondscapes and their leaves provide excellent shelter for koi too. Just keep in mind that taro plants don’t handle cold well, and they will need to be overwintered indoors in cool climates.

Mature taro plants grow between 3 and 6’ tall, and like other pond plants, they can help to filter the water in your koi pond and keep it cleaner for your fish. However, taro plants do contain calcium oxalate crystals, which can be toxic to fish. For this reason, you’ll want to keep your taro plants in shallow water or in pots where koi won’t be able to reach them.

8. Water hyacinth (Eichornia crassipes)

Purple flowering water hyacinth — Water hyacinths are no-fuss plants, but you do need to be aware of their potential for invasiveness in some areas, and know how to prevent them from becoming so.

Plant name:	Water hyacinth
Light requirements:	Full sun
Growing zone:	Zones 8 to 11
Maximum planting depth in water:	3 to 12” deep

With their pale purple flowers and bright green, leathery leaves, water hyacinths are sure to make a big impact in any koi pond. But these plants can be highly invasive in some areas, so you will want to be cautious where you plant them. If you need to dispose of water hyacinth or any other invasive aquatic species, always allow the plants to dry out fully in the sun before throwing them in the trash or adding them to your burn pile.

If you do decide to keep water hyacinth, you will be rewarded with an easygoing plant that doesn’t need much fuss. While koi fish may occasionally nibble on water hyacinth, these plants are generally less attractive to koi than water lettuce, watercress, and some of the other plants on this list. Like many other water plants, water hyacinth provides shelter and shade for koi, and it also helps to purify pond water and the plant’s blooms are attractive to pollinators too!

9. Cattails (Typha spp.)

Cattails on a pond's edge — Cattails are a classic pond plant. They have many edible parts, too!

Plant name:	Cattails
Light requirements:	Full sun to part shade
Growing zone:	Zones 3 to 10
Maximum planting depth in water:	18” deep

A pond favorite, many cattail species are native to North America, and they can be spotted growing wild in boggy areas and marshes. But cattails can also be intentionally cultivated around koi ponds, and their strong lines lend a bold, architectural feel to pond designs. Not to mention, some cattail species are edible, and their cooked rhizomes are said to taste like mashed potatoes!

When grown in ponds, cattails help to prevent erosion, but they also provide shelter for koi and other wildlife, and their flowers attract insects that koi fish can feed on. Cattail roots also shelter microorganisms that can break down organic matter in ponds and remove water pollutants as well. Cattails grow best in shallow water, but their roots can be submerged in up to 1 ½’ of water if needed.

10. Horsetail (Equisetum spp.)

Plant name:	Horsetail
Light requirements:	Full sun to part shade
Growing zone:	Zones 4 to 9 (most varieties)
Maximum planting depth in water:	Up to 3’ deep, depending on a variety

Horsetail plants are considered to be “living fossils,” and they’ve been around since dinosaurs ruled the earth. In fact, horsetail plants are older than flowering plants, and the original horsetails grew as large as trees… although they are much more diminutive today. Modern horsetail plants can grow between 2 and 4’ tall, but many varieties stay under 1’ in height.

Hardy and resilient horsetail plants can be found on most continents, and they can be invasive in some areas, so you’ll want to be careful when planting them. Gardeners are often drawn to horsetail plants because of their distinct appearance and their showy, segmented stems that look a bit like bamboo. But horsetail plants are cold hardy, and tough, and taller varieties can be grown in up to 3’ of water!

11. Sweet flag (Acorus spp.)

Sweet flag water plants — These plants will grow well in up to a foot of water.

Plant name:	Sweet flag
Light requirements:	Full sun to part shade
Growing zone:	Zones 4 to 10
Maximum planting depth in water:	6” deep

At first glance, sweet flag can look very similar to irises and cattails. But these semi-aquatic plants have a unique flowering structure called a spadix, which looks a bit like an underdeveloped ear of corn. Sweet flag plants are native to North America, and they are named for the sugary sweet aroma that these plants emit when their leaves are crushed.

Growing well in up to 1’ of water, sweet flag plants don’t grow as quickly as cattails and some of the other plants on this list, so they’re less likely to overwhelm a small pond space. Mature plants grow from 2 to 3’ tall, and their grass-like foliage will add much-needed color and texture to pond designs. When properly maintained, sweet flag plants will help to maintain the water quality in your pond, and they look attractive while doing it!

12. Duckweed (Lemna minor)

Small duckweed on a koi pond — Duckweed can grow rapidly and cover a pond's surface, but it can be easily skimmed and controlled.

Plant name:	Duckweed
Light requirements:	Full sun
Growing zone:	Zones 4 to 10
Maximum planting depth in water:	Floating plant

Duckweed is one of the most popular plants in aquascapes, and it’s even commonly grown in indoor aquariums. Colorful and easy to grow, duckweed is a floating plant that’s quite small in size. But duckweed plants reproduce rapidly, and in no time at all, duckweed can form a colorful mat over your pond’s surface that will provide food and extra shelter for your koi fish.

As with some of the other plants on this list, duckweed can be invasive in some areas, and it can overwhelm small ponds. However, excess duckweed can be managed by skimming extra plants out of pondscapes from time to time and allowing the plants to dry fully in the sun before disposing of them. Packed with protein, duckweed plants are a favorite snack food for koi, but because duckweed grows so rapidly, you won’t need to worry about losing some of your plants to voracious koi fish!

13. Watercress (Nasturtium officinale)

Watercress growing on a pond's edge — This is the same watercress that is grown as an edible plant.

Plant name:	Watercress
Light requirements:	Full sun to part shade
Growing zone:	Zones 3 to 11
Maximum planting depth in water:	2 to 3” deep

Watercress is one of the most famous water plants, and many gardeners grow watercress solely as an edible. But watercress is so much more than a leafy green to use in salads! This mat-forming plant also makes a welcome addition to koi ponds and other watery landscapes that need a bit more color.

Watercress will grow best in shallow water with a gently moving current, so make sure your koi pond has an adequate filtration system that moves the water about. While many growers enjoy watercress’ vibrant, green leaves, this plant also produces petite, white flowers that bloom from spring through summer. These plants do spread, though, so you may want to keep your watercress plants in mesh pots or floating planters to make them easier to maintain.

14. Water Smartweed (Persicaria amphibia)

Smartweed growing in a fish pond — Water smartweed can be grown completely submerged, where it will help oxygenate your pond water.

Plant name:	Water smartweed
Light requirements:	Full sun
Growing zone:	Zones 4 to 8
Maximum planting depth in water:	2’ deep

Water smartweed is a flexible plant in koi ponds. Depending on your space, you can keep this plant completely submerged to help oxygenate the water and filter out toxins, or you can grow water smartweed along the edge of your pond to provide shade and shelter for koi and local frogs too! Koi fish don’t find water smartweed plants to be particularly appetizing, but water smartweed’s pink flowers do attract insects, which your fish will happily gobble up.

If water smartweed looks familiar, that’s because there are about 900 different smartweed species, and some grow prolifically on land. In ponds, water smartweed can spread, so be sure to trim your plants every now and then to keep them under control. If you want lots of brilliant color in your koi pond throughout the growing season, water smartweed is hard to beat, and it will flower from summer well into fall.

15. Creeping Jenny (Lysimachia nummularia)

Creeping Jenny is popular in garden beds and planters, but can also be grown in a koi pond setup.

Plant name:	Creeping Jenny
Light requirements:	Full sun to part shade
Growing zone:	Zones 4 to 9
Maximum planting depth in water:	2” deep

Creeping Jenny is mostly kept as an ornamental in garden beds, and it’s commonly grown in porch planters too. But if you love creeping Jenny’s vibrant, chartreuse green leaves and brilliant yellow flowers, you may want to try creeping Jenny in your koi pond as well. After all, these plants adore moisture, and they can grow in up to 2” of water!

Creeping Jenny flowers from early summer through fall, and those flowers can lure insects to your pond for your koi fish to feast on. This plant also has a lovely, trailing growth habit, and creeping Jenny branches may spread across the shallows of your pond, providing shelter and shade for your koi fish in summer. In general, koi are not particularly fond of eating creeping Jenny plants, but they may nibble on a branch or two from time to time.

Frequently asked questions

Koi fish nibbling on pond plants — Koi pond plants help to shade fish, clean, and oxygenate water...among other things!

What plants will koi fish not eat?

Koi fish aren’t picky eaters, and they can nibble on just about any plant if they’re bored or hungry. However, some plants are less attractive to koi than others. If you’re looking for fish-proof plants, water poppies, and water irises are often ignored by koi.

Do pond plants oxygenate water?

Yes! Most pond plants will help to oxygenate the water, which can boost the health of your fish and your pond too. But plants can also improve water quality by removing pollutants and fish waste and reducing algae growth.

Do pond plants help to keep the water clear?

Yes! One of the most impressive benefits of pond plants is that they act like natural water purifiers, but they don’t need any electricity to keep them going. While you’ll still want to include a filtration system in your koi pond, pond plants can reduce harmful nutrients in pond water and outcompete algae as well.

How do I keep my pond plants alive?

Pond plants are very much like any other plant you’d keep in your garden. To keep pond plants happy, make sure your plants receive the light levels they need and sow your plants at the correct planting depth. Beyond that, you may need to overwinter cold-sensitive pond plants indoors if you live in a cold climate.

How do you overwinter pond plants?

Cold hardy plants can often be overwintered outdoors if your pond is deep enough; however, heat-loving plants or plants in shallow ponds may need extra winter protection. Most often, gardeners overwinter pond plants in a Styrofoam cooler in a garage or other area that will stay at about 40°F all winter. Pond plants will need to be kept cool and moist throughout the season to stay healthy, so be sure to water your plants every 2 to 4 weeks.

Why are my pond plants turning brown?

Some pond plants may naturally turn brown in autumn as they prepare for winter dormancy. But if your pond plants are becoming discolored during the growing season, they may be suffering from too much sun. Plants can also brown if they’re planted too deep in water or if their roots are allowed to dry out.

Summary

A nice planting of plants in a koi pond — Fast growing and resilient plants can handle the hungry appetites of koi fish.

Finding pond plants can be a challenge, but it’s even trickier if you add koi or other fish to the mix. Koi fish often gobble up pond plants, but fast-growing and resilient plants can handle it. So pick up a hardy pond plant or two this season… your koi fish will thank you for it!

The plants we’ve listed today are all ideal for koi fish ponds, but if you’re looking for even more pond planting suggestions, you may want to check out our guide on plants that thrive in soggy soil!