A Simple Guide To Pond Plants

Ever wondered if pond plants are important to the quality of your fish pond? Not only do they look great, but they provide wonderful benefits to your pond water and fish.

Our detailed guide explains why pond plants are important, what types there are and how you can plant these yourself.

Table of Contents	What type of pond plants are there?
What are pond plants?	What are the best plants for a garden pond?
What do pond plants do?	How do I know what plants to choose for my pond?
Why are pond plants important?	How to plant pond plants

What are pond plants?

Pond plants, as the name suggests, are plants which have adapted to living in aquatic conditions. This can be either in the water (submergent/emergent) or near the water in wet/boggy conditions.

Aquatic plants are a natural addition to ponds and should be welcomed. Aquatic plants will promote aquatic insect life which, in turn, will provide a steady food chain for its inhabitants.

By having pond plants, you can expect to see insects such as:

Pond skaters
Water snails
Water boatmen

As well as the larvae of insects, such as:

Caddisfly
Alderfly
Damselfly
Dragonfly

… to name a few.

Aquatic plants also provide excellent breeding grounds and nurseries for fish. Fish will often lay their eggs in or around aquatic plants and the juvenile fish (fry) will often occupy plant heavy areas to reduce the risk of predation. In these aquatic nurseries, the fish will live on an omnivorous diet of microscopic pond life which exists in and amongst the roots and stems of pond plants.

What do pond plants do?

Pond plants look amazing in ponds, but beyond simple aesthetics, there are lots of benefits to having aquatic plants in your pond.

Pond plants act as a natural filtration system. They consume nutrients such as Nitrate and Phosphate in order to grow. In doing so, they improve the water quality and out-compete nuisance algae plants. The result is better water with higher clarity.

In order to maximise the effect of this, it is important to use a combination of aquatic plants. By using a mixture of marginals, water lilies and deep-water oxygenators, you will starve pest algae of nutrients whilst also reducing the amount of light penetrating the pond - this will also keep the water cooler, making it very difficult for the algae to colonise.

Please note: while aquatic plants can help you combat algae, they will not work miracles in the height of summer. By pairing aquatic plants with adequate filtration and a sufficiently large UV light, you will experience much better results.

Why are pond plants important?

Pond plants are the backbone of a balanced aquatic ecosystem. In the same way land plants and trees provide oxygen for terrestrial life, pond plants do the same for aquatic life. Aquatic plants photosynthesise, consuming Carbon Dioxide and turning it into dissolved Oxygen. This allows aquatic animals to breathe but also stops water stagnating.

It is important to note at this point, that there is a specific group of submerged aquatic plants known as ‘Oxygenators’ which are best suited to this role in a pond. Examples of such plants include:

Ceratophyllum demersum (Hornwort)
Hottonia Palustris (Water Violet)
Myriophyllum verticillatum (whorl-leaf watermilfoil)
Ranunculus aquatilis (White Water-Crowfoot).

Plants can provide cover and shade for ponds and their inhabitants. This can reduce predation from animals such as herons, by reducing visibility. In addition to this, a well-covered pond rich in shade will often remain cooler. This again reduces algal blooms (as algae thrives in warm water) but also increases oxygen exchange.

Plants perform better in cooler conditions; therefore, by having a mixture of marginal, emergent and submerged plants, the productivity of the aquatic ecosystem will improve. Great examples of plants which will provide a pond with shade include the likes of:

Nymphaea (Water Lilies)
Pistia stratiotes (Water Lettuce)
Tall marginals such as Iridaceae (Iris)

What type of pond plants are there?

Pond plants come in a variety of forms. Some exist in deeper water while others exist in the moist ground at the edges of ponds and of course, there is everything in-between. Pond plants generally fall into one of the below categories:

Marginal Plants

Emergent

Planting Depth: 0-15cm

Marginal plants thrive in shallow water, usually at a depth of 15cm and upwards. Marginal plants are generally referred to as emergent, as the stems and flowers of the plants emerge from the water while the root systems remain below the water level.

Deep Marginal Plants

Emergent

Planting Depth: 15-40cm

While some marginal plants prefer shallower water, there are certain species which will tolerate or even prefer deeper water of up to 45cm. Much like standard marginal plants these are also known as emergent as the flowers and stems will emerge from the water.

Deep Water Plants

Emergent and Submergen

Planting Depth: 40cm+

Deep water plants can vary from floating emergent plants, such as Water Lilies, to fully submerged plants, such as Elodea. They are without a doubt, the most valuable plants in the pond as they work the hardest.

Deep water plants remove lots of excessive nutrients synonymous with hair algae and also enrich the water with lots of oxygen. Having deep water plants in your pond during the warmer months when saturated oxygen levels are low, is really important.

Floating Plants

Floating plants are found on the surface of the pond. Unlike deep water plants, floating plants are not connected to the floor of the pond via root systems and stems. Instead, they generally have a self-contained root system which is adapted to living in these conditions.

Floating plants are incredibly low maintenance, providing shade to the pond and acting as a pontoon for wildlife, such as frogs and newts, to rest on.

What are the best plants for a garden pond?

There is a phenomenal amount of choice out there when it comes to pond plants, but to save you some time, we have listed some of our favourites below:

Angallis Tenella – Bog Pimpernel

British hardy perennial with a carpet of small evergreen leaves.
Will thrive either in boggy soil at the edge of ponds or in shallow margins up to 15cm depth.
Flowers in late-Spring to mid-Summer with an abundance of small dusky pink flowers.
Extremely proficient at spreading through ponds horizontally.

Cardamine Pratensis – Cuckoo Flower / Lady's Smock

Subtle yet elegant British Native aquatic plant.
Prefers boggy areas and shallow margins up to 15cm deep.
Herbaceous perennial leaves with stems up to 30cm containing an abundance of pale lilac flowers April – June.
Fantastic for attracting wildlife such as Orange-Tip Butterflies.

Cotula Coronopifolia – Brass Buttons / Buttonweed

Prefers boggy ground or shallow margins up to 15cm depth.
Stems are slow growing with aromatic, green foliage which extend up to 20cm high.
Creeping summer annual with small golden yellow flowers which resemble buttons, hence the nickname ‘Brass Buttons’.

Houttuynia cCrdata ‘Plena’ – Orange Peel Plant

Marginal plant which prefers its roots in the water up to a depth of around 15cm.
Fast spreading perennial plant with an abundance of heart shaped leaves.
Dainty white flowers erupt from the foliage June – July.
Extremely hardy and will tolerate a broad range of conditions from full-shade to full-sun.

Iris Pseudacorus -Yellow Flag Iris

Grows best with its roots submerged up to 20cm and is an ideal candidate for pond margins.
Wild British native marginal and probably the most common Iris seen in UK wetlands.
Vigorously growing perennial with long, sword-like foliage and bright yellow flowers which blossom May-June.

Lychnis Flos-Cuculi – White Robin

This aquatic perennial will survive in wet/boggy ground or in shallow pond margins with its roots submerged to depths of 15cm.
A white-coloured variant of the wildflower ‘ragged Robin’.

Produces pretty clusters of delicate star-like white flowers on tall upright stems throughout the summer months.

Mentha Cervine – Water Spearmint

Beautifully fragrant herb, which grows well in boggy soil and pond margins up to depths of 15cm.
Flowers during the later summer months July – October, with beautiful lilac flowers which are highly fragrant and attract bees, butterflies and other pollinating insects.

Caltha Palustris – Marsh Marigold

Can grow up to 50cm tall and is best suited to boggy ground or pond marginal depths of up to 15cm.
British native wetlands plant with rich green heart shaped leaves and clusters of bright yellow flowers which resemble large buttercups.
Will generally flower in April however, if cut back, will on occasion flower again in August.

Geum Rivale – Water Avens

Water Avens prefer partial sun and like their roots submerged in pond margins up to depths of around 15cm.

Water Avens foliage resembles that of strawberry plants, however, Water Avens grow to heights of around 30cm, with beautiful yet unusual purple/pink bell-shaped flowers which are held above the plant on stalks.

Lythrum Salicaria Robert – Loosestrife

A well-loved, perennial, marginal, aquatic plant which prefers its roots submerged up to depths of around 15cm.
Relatively tall, getting to heights of around 90cm with spikes of candy pink flowers (July – September) which are irresistible to pollinating insects.
These beautiful plants provide height, structure and colour to a pond.

Butomus Umbellatus – Flowering Rush

The flowering rush prefers to have its roots in water and is adapted to living in pond margins as deep as 25cm.
A tall rush-like plant extending to heights of 60cm - 100cm which produces lush pink flowers extending beyond the foliage, June – August.

The foliage of Butomus turns from red to dark green as the plant matures through the growing season.

Acorus Calamus Variegatus – Variegated Sweetflag

Prefers to have its roots submerged below the water up to a depth of around 15cm.
This native marginal wetland plant has attractive, variegated sword-like leaves displaying contrasting colours of cream and rich green.
It has a rich, sweet aromatic smell and adds height to your pond margins.

Pontederia Cordata – Pickerel Weed

Likes its roots submerged in the shallow margins of ponds up to a depth of 15cm.
Very attractive marginal plant with cupped heart-shaped waxy green leaves with spikes of blue flowers which bloom in late Summer (June – August).
This plant is excellent for attracting breeding dragonflies and damselflies.
Also available in a much taller variety which has longer stems and flower stalks - Pontederia Cordata Lanceolata.

Sagittaria Sagittifolia ‘Flore Pleno’ – Double Japanese Arrowhead

This plant grows to a height of around 60cm and prefers its roots submerged in marginal ponds up to a depth of around 20cm.
This is the double flower-headed form of the Japanese Arrowhead.
Deep green, arrow shaped leaves with linen White double flowers, resembling pompoms.
Flower blooms generally appear between June – September.

Iris Sibirica – Siberian Flag Iris

This variety of Iris actually prefers boggy soil on pond edges rather than having its roots submerged.
Native to parts of Europe and central Asia.
It is a perennial plant which grows up to 1.2m tall with sword-shaped, green leaves.
Flowers are purple/blue in colour with three-way symmetry typical of Iris, appearing generally June-July.

Typha Angustifolia – Lesser Bulrush

Bulrush like having their roots fully submerged up to depths of around 30cm.
Rapid growing, deeper marginals with long sword shaped leaves, growing to a length of up to 150cm.
These native plants will display chocolate brown coloured seed heads from June – September.

Houttuynia Cordata ‘Chameleon’ – Chameleon Plant

This particular plant prefers its roots submerged in shallow pond margins up to 15cm.
Chameleon plants are well noted for their ever-changing, vividly coloured foliage demonstrating shades of green, yellow and red.
The foliage will develop as the seasons progress, and blooms of delicate white flowers will appear June – August.
Will happily tolerate shade and can spread rapidly.

Nymphaeaceae – Water Lilies

There are dwarf varieties and larger varieties all with specific planting requirements however, as a rule of thumb, planting depths should not exceed 100cm.
Water lilies are emergent, deep water aquatic plants i.e. the plants root system exist at the bottom of the pond while the foliage extends on long stems to emerge and float on the water surface.
Water lilies are most commonly associated with their striking flower displays which float on the water surface alongside the foliage (pads). These flowers are extremely decadent, loaded with brightly coloured petals covering a broad range of colours.

There are over 50 recognised species of water lily as well as a number of hybrids. Some of our favourite varieties include: Alba, Joey Tomocik, Darwin, Marliacea Carnea, Charles de Meurville and Marliacea Chromatella.

Pista Stratiotes – Water Lettuce

Water lettuce are examples of floating aquatic plants.
This tropical species will tolerate UK summers.
Pistia has thick, light green, soft leaves, which form a rosette while the root system hangs from the base of the plant, below the water surface.

Simply place the water lettuce in your pond and watch them grow and spread. Unfortunately, due to their tropical origins, Water Lettuce will not survive UK winters. It is possible to keep them alive in a heated indoor aquarium with plenty of natural light over winter.

Oxygenators

‘Oxygenator’ is a broad term for a variety of deep water submerged plants which typically exist in ponds. In wildlife ponds, they are generally considered to be one of the most important plants as they provide its inhabitants with oxygen while providing shelter for aquatic life.

Oxygenators can be bought in small bunches held together with foam and lead weights or alternatively, planted in aquatic pots. Typical examples of oxygenators include: Scirpus Cernuus, Myriophyllum Crispatum, Ceratophyllum Demersum and Elodea Crispa.

How do I know what plants to choose for my pond?

Whether you’re looking to decorate your pond or you’re hoping that they will improve the pond’s natural balance, always research which plants will be most suitable for the pond size and location.

There is a plethora of information available online, but equally you can ask the team at Complete Koi & Aquatics for advice on this. We have a large selection of extremely high quality aquatic plants available in the shop which are suitable for a variety of planting situations.

Research, plan, then plant!

How to plant pond plants

1. Select a basket.

Aquatic plants placed into lined or fibreglass ponds should be planted in aquatic planting baskets due to a lack of substrate at the bottom of the pond. The baskets typically have permeated sides, allowing exchange of water and helping the plant sink. They come in a variety of shapes and sizes depending on the size of the plant you are potting.

2. Choose a liner.

Once an appropriate basket has been selected, it is recommended to line the basket with muslin cloth or hessian sheets. This continues to allow exchange of water to the roots but will limit the amount of substrate leaving the basket, which will ultimately make the pond dirty.

3. Get planting!

Once this has been completed, it is time to move on to your plant. It may be that you’re repotting something which has otherwise outgrown its current pot, or you may have an entirely new plant. In any circumstance, place the aquatic plant in the desired pot ensuring the root system is well contained.

Once this has been done, you should then fill the pot with aquatic compost, taking time to move the soil around the root system and covering it. It is important to leave some room at the top of the basket as you will want to finish the potting with a thin layer of gravel designed to stop the substrate floating out of the pot, whilst also helping the basket sink.

4. Your aquatic plant is now ready!

It is good practice during this stage to fill a large bucket with pond water and place the prepared basket into this before placing it in your pond. This will wet the substrate, hessian and gravel, thereby dislodging any loose material which will otherwise end up in your pond.

When the pot is saturated and no further particles are leached from the pot, this can now be placed in your pond. For marginals, it is a case of positioning them from the edge.

With deep water aquatic plants, positioning can be more challenging. We would suggest putting some string through the basket loosely. This can then be dropped to the bottom slowly, before pulling the string free of the basket.

FAQs

What plants clean pond water?

Aquatic plants do not provide ponds with mechanical filtration. They do however, provide a certain level of biological filtration which can help reduce pest algae such as blanket weed.

Aquatic plants consume nutrients in the water, such as nitrate and phosphate, which algae would otherwise feed on. By having desirable aquatic plants in your pond, you will limit excess nutrients in your pond which will in turn, produce better water clarity.

So, whilst pond plants do not directly clean the water, by having them in your pond, you may experience better clarity.

What are the best oxygenating pond plants?

At Complete Koi & Aquatics, we like the following:

Scirpus Cernuus – Fibre Optic Plant

Evergreen oxygenator (providing the Winter is mild) with green grass-like stems which extend up to 20cm.
Tiny white flowers appear during June – August, on the tips of the stems which look like sources of light, hence the nickname Fibre Optic Plant.

Myriophyllum Crispatum - Upright Water Milfoil

This oxygenator can either be planted as a marginal or fully submerged up to depths of 40cm.
Perennial aquatic oxygenator with bright green feathery foliage.
Myriophyllum plant stems typically extend 60cm.

Ceratophyllum Demersum – Hornwort

Deep water native oxygenator which will grow up to depths of 60cm.
This is a fantastic plant as it is completely adapted to UK weather and so will thrive in almost any pond situation.
Typically floats freely in the pond and will die back in the winter.
As spring comes round, modified stem buds will begin to grow again with the warming temperatures.

How many oxygenating plants do I need for my pond?

Oxygenating plants usually come in small bunches however, they can grow incredibly quickly provided the conditions in your pond are suitable. It is not advisable to put any oxygenators in a Koi pond, as the Koi will eat and destroy them which can cause a lot of mess.

In goldfish ponds and wildlife ponds, you can put as many oxygenators in as you desire. If they grow rapidly, you may need to remove some. Equally, if they die back, you may want to add some more. Add as many oxygenators as you feel comfortable with.

When should I plant my pond plants?

Pond plants all have specific requirements however, when it comes to planting, it is recommended to plant in the warmer months (e.g. March – October).

Many aquatic plants will have specific growing windows and will often die back in the winter. In relation to this, many pond plants simply aren’t available in the winter. While this is a general rule, it is worth doing some research on the pond plants you desire and enquiring about availability and best planting times.

Where can I buy pond plants?

At Complete Koi & Aquatics, we stock a large variety of pond plants. These plants, as discussed above, are hugely seasonal so our stock may change throughout the year.

Please feel free to come and visit us to see what pond plants we have available and to get expert advice on what you should add to your pond. Alternatively, you can contact us online or over the phone for any advice and support.