Aquatic plants

Anglo Aquarium’s Policy on Invasive species

Anglo Aquarium is working in conjunction with DEFRA and OATA to protect both our environment and our industry. Ponds, rivers and lakes are essential for wildlife, we are committed to helping people create beautiful water features while protecting our environment.

The most important point; under no circumstances should garden plants be disposed of in the wild. Even native plants placed in the wrong location cause environmental damage. It is essential to dispose of them correctly, either compost them or take them to your local refuse centre.

Certain plants, including five aquatics, have been identified as having the potential to damage the ecosystem in the UK given the opportunity. This page is designed to ensure you avoid these plants, while not restricting your choice unnecessarily, after all the UK is renowned for our plant collectors from the Victorian era and hence our attractive English gardens.

Plants that should not be sold in the UK

Azolla filliculoides

Azolla filliculoides image

Commonly known as Water fern, Fairy fern or Fairy moss

In a hot summer this plant can quickly cover vast areas with a dense mat of foliage. It prevents light being able to penetrate the mat to the water below killing submersed oxygenating plants and restricting the growth of many others. Because of its tiny size it is very difficult to remove and almost impossible to eliminate completely. As it reproduces from tiny fragments, it is easily transported by travelling wildlife or by people transferring plants from one pond to another.

Alternative plants that can be used are Hydrocharis morsus ranae (frogbit) native but slow growing, Eichhornia crassipes major (water hyacinth) fast growing but not hardy and large so very easy to remove

Crassula helmsii

Crassula helmsii image

Also known as New Zealand pigmyweed, Australian Swamp Stonecrop, New Zealand Stonecrop, Crassula recurva, Tillia recurva and Tillaea helmsii.

Again this plant can regenerate from tiny fragments and hence easily spread to new areas. Again it forms a dense mat reducing light levels and can spread over moist ground displacing other plants.

Hydrocotyle ranunculoides

Hydrocotyle ranunculoides image

Also known as Floating Pennywort, Water pennywort or Pennywort.

This plant can grow at an astonishing 20 cm per day, rapidly forming a thick mat across a pond or slow moving water. Not to be confused with slower growing varieties such as Hydrocotyle nova Zealand (Miniature pennywort) or the variegated Hydrocotyle sibthorpioides variegata (Crystal confetti)

Ludwigia uruguayensis

 Ludwigia uruguayensis image

Also known as Water primrose, Lugwigia grandiflora, Ludwigia peploides or incorrectly as Jussiaea.

Unlike the other plants in this category, which we have not sold for years, until 2010 we did sell this plant as we had mixed messages coming from various sources. Due to co-operation between the Government and the Aquatics trade there is now the clarity missing before and we support the joint decision and de-listed it. The Government is highly appreciative of the support it has received from OATA, HTA and companies such as ourselves who have been so proactive in a voluntary sales ban.

Myriophyllum aquaticum

Myriophyllum aquaticum image

Also known as Parrot's feather, Myriophyllum brasiliense, Myriophyllum proserpinacoides or Brazilian water-milfoil.

This plant can completely take over a pond, again reducing light. In addition it is primarily sold as an oxygenating plant but is particularly poor at this role as the submersed leaves tend to rot hence not oxygenate. As an alternative, why not try Myriophyllum brasiliensis ‘red stem’, a much slower growing form. Or there are two natives, both Myriophyllum spicatum (Spiked water milfoil) and Myriophyllum verticillatum (Whorled water milfoil) are far better oxygenating plants.

Photographs of plants we do not stock, kindly supplied by Non Native Species Secretariat

Currently no pond plant is banned from sale in the UK. The above plants are being considered for sales prohibitions but no decision has been made. We would prefer rather than prohibitions, the industry regulates it’s self and hence we do not supply these plants and would strongly advise against their sale.

Plants under consideration

DEFRA and the Welsh Assembly Government are continually checking which plants could potentially cause damage. One plant still under consideration is Lagarosiphon major.

Lagarosiphon major

> Lagarosiphon major image

Often called Curly water thyme, Elodea crispa or Crispa

This plant is by far the best oxygenator and has been sold for many years yet we rarely hear of issues from our customers. This plant can grow fast but does not in all areas, however it can be easily trimmed or harvested. During the season there is a shortage of this plant, hence in large ponds and lakes where the plant grows faster than required, it is easy for pond owners to find a plant collector willing to maintain the plant in exchange for collecting it, often they may be able to carry out further maintenance free of charge or at a reduced rate as well. In small ponds it is easy to maintain.

We have noticed Lagarosiphon tends to grow in certain areas and not in others, hence we believe this is due to specific water conditions and/or temperatures and is more likely to be invasive in areas such as Southern Ireland and Cornwall where we advise it is best avoided.

Alternatively why not try a native alternative. Ceratophyllum demersum (Hornwort) is the best oxygenating native but can grow as fast or faster. Fontinalis antipyretica (Willow moss), Potamogeton crispus (Curly pondweed) and Ranunculus aquatilis (Water crowsfoot) are among the better native oxgenators but they are only on sale, and indeed growing well, at certain times of the season. For these and other oxygenators please our Catalogue.

Plants that are not a threat

A few years ago when the Be Plant Wise initiative was started, there were some bizarre claims caused by mixed and confused messages. Below we try to clear up some of these confusions.

Eichhornia crassipes major

>Eichhornia crassipes major image

Often called Water hyacinth

Although this plant is one of the world’s worst weeds, it is not hardy and rarely survives winter in an unheated greenhouse in the UK. This plant is of absolutely no threat to our flora and fauna. It grows well in the season, is a large plant so very easy to remove, provides shade and shelter for pond wildlife and is very good at removing nitrates from the water, helping to reduce algae. We recommend removing the plants as they start to die back and add them to the compost heap. This permanently removes the nitrates from the water and is an excellent fertiliser for the garden too!

Pistia stratiotes

> Pistia stratiotes image

Often called Water lettuce

This plant rarely survives UK winters even in a heated greenhouse and again is of absolutely no threat to our flora and fauna in the UK. It makes an attractive alternative to Eichhornia crassipes major but can easily be scorched by cool weather, and is killed by even a very mild frost.

Elodea canadensis

Elodea

Often called Canadian pondweed

This plant came into the country in the 1800s and is now classed as naturalised to the British Isles. It grows extremely rapidly in new natural ponds for seven years, it then settles to become a very ordinary oxygenating plant. You may therefore prefer to use one of the true native plants listed under Lagarosiphon major. Please note Elodea Canadensis is the only oxygenator to be naturalised rather than native.

For more information please see;

Non Native Species Secretariat