9 Types of Aquatic Plants

Aquatic plants always lend interest to a body of water, whether it is a container of water small encough to fit on a plinth in the garden or a pond that takes up several acres. Aquatic plants can be placed in the wet ground just by the water, they can be submerged underwater, or they can float on the water. Some have spectacular, fragrant flowers while other water plants provide food and shelter for aquatic animals such as fish or amphibians. Submerged plants are prized for getting needed oxygen into the water, which would be useful for koi fish to thrive in a pond. Here are nine different types of aquatic plants to consider for a koi pond:

  1. Crystalwort
  2. Canadian Waterweed
  3. Water Violet
  4. Water Milfoil
  5. Water Lily
  6. Water Starwort
  7. Pondweed
  8. Fairy Moss
  9. Arrowhead
Aquatic plant landscape custom designed and planted around a koi pond for a jungle-like vibe.
This gorgeous garden pond was installed by Hector and his crew for one of his clients. © Stonewall Creek.


[Riccia fluitans]
This aquatic plant is a type of liverwort, which is a fungus related to moss. It does not produce seeds but produces instead. Its stems and leaves are not differentiated but form structures called thalli. Crystalwort usually floats just beneath the surface of the water, forms dense mats, and can be submerged if the pond water conditions are right. Some varieties of crystalwort have reddish-violet scales on the underside of their thalli.

Canadian Waterweed

[Elodea canadensis]
This submerged plant has whorled leaves that are a little more than 1/3 of an inch long. The plant thrives in flowing and standing water that’s rich in nutrients, especially calcium. It produces male and female flowers that are solitary and tubelike, with the tube reaching up to the surface.

Other varieties of Canadian waterweed float on the surface as rosettes of thick, stalked leaves that are about an inch to an inch and a half around. They reproduce through runners (twining just like strawberry plants) although they do produce unisexual flowers.

Water Violet

[Hottonia palustris]
This plant has beautiful foliage that resembles fern. The foliage is beneath the water but the pale purple flowers rise above the water line in long, erect stems. The flowers arrive in May. Water violets thrive in acidic water that isn’t too rich in nutrients and does well in partial shade.

Water Milfoil

There are about 40 species of water milfoil. They have submerged leaves that come in whorls and are deeply indented. In some species, they’re toothed. The flowers of the water milfoil are small, come in groups of four and are found on the leaf axils on the shoots that rise above the water. Water milfoil does best in hard water and moderately nutritious soil that’s largely sand or gravel. The plant needs direct sunlight and is propagated through cuttings.

Water Lily

The water lily is one of the more sought after aquatic plants with its glorious flowers that arrive in the summer. These flowers can bloom to be white, pink, red, gold, blue, or purple. There are many species, and they are found around the world. The leaves of the water lily both float atop the water and are submerged. The floating leaves are glossy deep green, famously plate-shaped, and have a notch. Water lilies have a corm-like root, and if a corm is planted in mud, it will send up flowers and leaves quickly. We have water lilies displayed at our pond shop that can give you ideas on how to combine them with other plants and/or koi.

Clustered lily pads and water lettuce floating atop a koi pond near boulders.
Water Cabbage and Water Lilies. © Stonewall Creek 2021

Water Starwort

Some species of water starwort are submerged while others have foliage that peeks just above the surface in shallow water. This pond plant is related to the plantain and has tiny, delicate leaves on branched stems that are 4 to 12 inches long. The flowers are even tinier and do not have petals or sepals. They can mainly be told apart by the white bracts found at the flower’s base.


Many species of this aquatic plant resemble seaweed, and their leaves wave about beautifully in flowing water. The species that have broad leaves produce flowers that are found above the water and disperse their pollen through the wind. The species with more seaweed like leaves disperse their pollen through the running water. This water plant grows from a rhizome and produces flowers in the summer months. Potamogeton isn’t too fussy about the pH of the water as long as it isn’t too salty and can stand some drying out. It is best to breed pondweeds through rhizomes.

Fairy Moss (Mosquito Fern)

This floating plant is also called a water fern or duckweed fern, even though it doesn’t particularly resemble ferns. The leaves are small, bluish-green, and overlapping; Interestingly, this aquatic plant is symbiotic with a bluish-green algae that gives it its color. These algae fix nitrogen, which the fairy moss then uses. In return, the plant protects the algae and gives it carbohydrates. In bright light, fairy moss can grow until it blankets the entire surface of the water.


The arrowhead plant’s common and botanical name, Sagittaria, gives a hint to the shape of its leaves; although some species have leaves that are oval, cordate, or linear. They can be submerged or above the water. The flowers come in threes with the lower flowers being female and the upper flowers male. In many species, the female flowers bend backwards after they’ve been fertilized. Arrowhead is also known as katniss. Sometimes in the spring or late fall tubers rise to the surface. They can be collected and eaten, which gives the plant its other name of swamp potato.

Our team at Stonewall Creek specializes in building and maintaining koi ponds, which usually includes our aquatic plant services. If you’re interested in learning more, please give us a call at (702) 274-2247 and we’ll be happy to assist.