Oxygenating Pond Plants – Picking Oxygenators for Your Pond

Oxygenating Plants – Learn & Grow

Oxygenating plants play an important role in maintaining the health of a pond, their submerged foliage providing food and cover for wildlife and competing with algae for minerals and nutrients, as well as helping oxygenate the water, of course!

Picking oxygenators for your pond is much like selecting any other plant – a question of striking the right balance between personal taste, the overall planting regime, local conditions and the intended purpose. The good news is that there are plenty of suitable candidates, so you shouldn’t have any problems finding something suitable and even the smallest of garden centres usually have more than enough choice to meet most needs.

That said, the range of plants can sometimes be a bit daunting and many of the more unusual or exotic varieties are not sufficiently hardy to cope with a full-on British winter, so as a starting point, here’s our pick of the tried-and-tested best for you to consider.

Common types of Pond Plants

Oxygenating pond plants, marginal pond plants, pond edge plants, floating pond plants, floating pond water lilies and deep water pond plants.

Six Of The Best Oxygenating Pond Plants

1. Hornwort (Ceratophyllum demersum) – Naturally Oxygenating

A well established favourite, this native plant has branched stems with dense “bottle-brush” whorls of deep green foliage. A hardy perennial, winter care could hardly be easier – the old stems sink in autumn and new ones emerge in the spring. It is a particularly good candidate for deep water and can be propagated in early summer from cuttings or by dividing clumps and since it does not root, its growth is very simple to keep under control.

2. Curly Pondweed (Potamogeton crispus) – Naturally Oxygenating

Another British native, the curly pondweed makes an interesting-looking addition, varying in shade from green to red/brown and with 4 inch (10cm) wavy-edged leaves which make it look more like a small seaweed than a typical freshwater plant. As an additional bonus, it also produces delicate pink/white flowers above the surface in early summer.

3. Water Milfoil (Myriophyllum spicatum) – Naturally Oxygenating

Fine feathery foliage adorning long trailing stems make this another attractive candidate for a small pond plant – even the smallest. It can be planted in depths of up to 3ft (90cm) and from May into August it will hold a succession of reddish-green flowers about an inch (25cm) or so above the water. M. spicatum is a native, but other milfoils are sometimes to be seen for sale – though not all of them are hardy, so it pays to check!

4. Water Violet (Hottonia palustris) – Naturally Oxygenating

As a group, oxygenators don’t tend to go in for much in the way of big floral displays, but this plant is a bit of an exception, producing – as you might expect from the common name – violet flowers on stems up to ten inches (25cm) above the water-level. It is not the easiest pond plant to get established, particularly in hard water areas, but it does well once it is and the mix of bright green, feathery foliage and showy blooms makes it well worth considering for water up to 2ft (60cm) deep.

5. Hair Grass (Eleocharis acicularis) – Naturally Oxygenating

For shallower water, this plant, also sometimes called Slender Spike Rush, is hard to beat, creating a dense mat-like underwater “lawn” a few inches high. Although it is probably more familiar as a cold water aquarium plant, many pond-keepers have found it an excellent alternative oxygenator for use outdoors. Ideal for depths between 2 and 12 inches (5–30cm) and suitable for small ponds, tubs and water features, it is easy to propagate by splitting clumps in late spring.

6. Water Starwort (Callitriche verna) – Naturally Oxygenating

Starwort is a great candidate for wildlife ponds, the dense mass of small oval leaves organised in the star-shaped rosettes, which give it its common name, being a haven for all manner of pond-life and particularly aquatic insects. Like the water violet, it can be a little difficult to get going, but its wildlife value makes it definitely one to consider.

Best Of The Rest – Naturally Oxygenating Pond Plants

There are, of course, plenty of other kinds of oxygenators to choose from, including:

• Willow moss (Fontinalis antipyretica) – a good choice for ponds with spawning fish or wildlife, and tolerates the full range of sun or shady conditions.
• Mare’s tail (Hippuris vulgaris) – more familiar as a marginal, it can be grown in deeper water as a very effective oxygenator (but don’t confuse this with the “horsetail” – a pernicious garden weed! )
• Water buttercup (Ranunculus aquatilis) – suitable for almost any pond, this plant brings plenty of interest, with white buttercup flowers and different foliage above and below the water.
• Goldfish weed (Lagarosiphon major) – also sometimes sold as Elodea crispa, it is a great oxygenator, but although it is less invasive than E. canadensis it will still need to be kept in check.

Although water plants can sometimes be a bit awkward to establish or slow to get going, if you plant a few different varieties, you should soon have a pond to be proud of, but whatever you eventually buy, do remember not to overdo things, however tempting it may be. Those plants will grow soon enough – so no more than five individual plants or bunches per square metre, or you’ll be forever pulling out the excess!

Read more: Worried about lack of oxygen in your pond? Check for these signs

Other great oxygenating pond plants

We suggest having about 2 bunches of oxygenating plants 9 cm pots per surface m2 

What is the best oxygenating plant for a pond?

There are several great oxygenating plants to consider for your pond. For spring and winter, consider using water-crowfoot (Ranunculus aquatilis). In summer and autumn, hornwort (Ceratophyllum demersum), pondweed, or waterweed can be good choices. Mare’s-tail (Hippuris vulgaris) and water violet (Hottonia palustris) are also well-known oxygenating plants that can work well in a pond. Other great options include arrowhead (Sagittaria subulata), eelgrass (Vallisneria), fanwort (Cabomba), red rotala (Rotala macrandra), water sprite (Ceratopteris thalictroides), and water wisteria (Hygrophila difformis).

What are the best pond plants to remove ammonia?

If you’re looking for freshwater plants to absorb ammonia in your pond, Amazon swords and hornwort are great choices. Java moss and other resilient plants that don’t require special lighting can also be effective at absorbing ammonia.

What plants should not be in a pond?

While many plants can be beneficial for a pond ecosystem, some should be avoided due to their invasive nature or potential to cause harm. Curly waterweed (Lagarosiphon major), Canadian pondweed (Elodea canadensis), and Nuttall’s pondweed (Elodea nuttallii) should be avoided, as they can quickly take over a pond and outcompete native plants. Water hyacinth (Eichhornia crassipes) and water lettuce (Pistia stratiotes) should also be avoided, as they have the potential to grow out of control and cover the surface of the water, blocking sunlight and reducing oxygen levels.

What are the best pond plants to stop algae?

The best pond plants to prevent algae growth include submerged plants such as hornwort and anacharis, which are efficient at absorbing excess nutrients in the water. In addition, floating plants like water hyacinth and water lettuce can help to shade the water, reducing the amount of sunlight available for algae to grow. Marginal plants such as cattails, irises, and reeds can also be effective, as they take up nutrients from the water and create natural filters.

What is an inexpensive way to oxygenate a pond?

One of the most cost-effective ways to oxygenate a pond is to install a waterfall or a fountain. These devices create water movement, which increases oxygen levels in the pond. Another option is to add a small air pump or diffuser to the pond, which can also increase oxygenation. Additionally, adding aquatic plants such as water lilies or hornwort can provide oxygen during the day through photosynthesis.

Does rainfall add oxygen to a pond?

Rainfall can help to increase oxygen levels in a pond by promoting aeration. As the raindrops hit the surface of the water, they create ripples and bubbles, which in turn help to mix the water and increase oxygenation. However, it is important to note that rainwater can also introduce nutrients and contaminants to the pond, which can lead to other water quality issues.

What are the signs of low oxygen in a pond?

Low oxygen levels in a pond can cause fish to gather near the surface of the water or near sources of aeration, where they may be seen gasping for air. In addition, fish may become less active or show signs of stress, such as flashing or rubbing against objects in the pond. If left untreated, low oxygen levels can lead to fish kills and other negative impacts on the pond ecosystem.

How can water be naturally oxygenated?

Natural methods of oxygenation include sub-surface aquatic plants, which release oxygen into the water through photosynthesis, and aeration caused by wind, waves, and waterfalls. Introducing aquatic plants such as water lilies or hornwort to a pond can also help to increase oxygen levels during the day. In addition, reducing nutrient inputs to the pond through measures such as limiting fertilisation and managing animal waste can help to improve oxygen levels.

What are some ways to increase oxygen levels in water?

Several methods can be used to increase oxygen levels in water, including adding aeration devices such as fountains or diffusers, incorporating aquatic plants into the water, and increasing water movement through the use of pumps or waterfalls. In addition, reducing nutrient inputs to the water and managing the water temperature can help to improve oxygen levels.

How many oxygenating plants should I have in my pond?

It is recommended to have 2-3 oxygenating plants per square meter of pond (also to prevent overcrowding) surface. The exact number of plants needed will depend on the size of the pond and the species of plants being used. Too few plants may not produce enough oxygen for the pond, while too many plants can lead to overcrowding and decreased oxygen levels during nighttime hours.

Can water lilies oxygenate a pond?

Water lilies do not produce oxygen through their roots but instead release oxygen through their leaves and flowers during daylight hours through the process of photosynthesis. They also provide shade, which can help to reduce the growth of algae in the pond. Submerged plants or oxygenators such as hornwort, anacharis, or parrot’s feather are better options to oxygenate your pond.

Do pond plants consume oxygen at night?

During the night, plants undergo respiration, a process that uses oxygen and releases carbon dioxide. Submerged plants and algae, which are the primary oxygenating plants, can deplete oxygen levels in the water during the night. However, during the day, these plants use photosynthesis to release oxygen and produce food for themselves and other organisms in the pond.

Is it possible to oxygenate a pond too much?

In a typical pond, it is unlikely to have too much aeration. However, in certain circumstances, excessive aeration or supersaturation can occur, which can lead to dangerous conditions for fish and other aquatic organisms.

Which aquatic plant produces the most oxygen?

Some aquatic plants, such as hornwort, eelgrass, green cabomba, and red Ludwigia, are known to produce high amounts of oxygen through photosynthesis. These plants are effective oxygenators and can help maintain healthy oxygen levels in a pond.

What plants can help prevent algae growth in a pond?

Floating plants such as water lilies and lotus can provide shade and reduce the amount of direct sunlight reaching the pond, which can help control algae growth. Additionally, submerged plants such as anacharis, hornwort, and parrot’s feather can release oxygen into the water, which can also help prevent algae growth.

Can oxygenating plants keep the pond water clear?

Oxygenating plants can help to maintain healthy water conditions in a pond by releasing oxygen and absorbing excess nutrients from the water. In doing so, they can help to prevent the growth of algae and keep the water clear. However, it is still important to maintain proper filtration and water chemistry in the pond.

Do oxygenating plants need soil to grow?

Most oxygenating plants require some type of substrate to anchor their roots, absorb nutrients, and provide oxygen to the plant. Some species can root in the pond’s silt or clay, while others require added aquatic soil. Ceratophyllum Demersum or hornwort is an exception, as it can float freely in the water and does not require soil to grow.