A guide to plants you can use in place of invasive non-native species.

Help protect the environment by using these plants in place of invasive non-native species.

Plants are vital for our health and the environment, they improve air quality, boost our mood, help to offer climate change resilience and provide a home for wildlife. 

Many of the plants in our ponds and aquaria are not native to the UK – they have been introduced from all over the world by people. While non-native plants can help us to create beautiful ornamental displays to enjoy, some become invasive and can cause problems for you and the environment. 

Although only a small minority of non-native plants are invasive, the impact they can have is extensive and may be irreversible. Aquatic plants are a particular problem due to the speed at which they can spread and the impact they can have on important aquatic habitats, such as lakes and rivers.

Here are a few examples of the impacts of invasive non-native aquatic plants:

• Crowding out native plants impacting on other species which rely on them for food or shelter
• Competing for space, light and nutrients
• Removing oxygen from the water, harming fish and other wildlife
• Blocking up waterways interfering with fishing, boating, and other activities
• Increasing the risk of flooding 

Aquatic plants can quickly outgrow their space and cause problems in your pond, and the environment. They may re-grow from tiny fragments, so that no matter how hard you try to eliminate them, they keep on appearing. Trying to get rid of problem plants 
from natural habitats, especially important nature conservation sites, is expensive and difficult. Often complete eradication of such plants from the wild becomes impossible, and millions of pounds are spent each year to limit their spread. 

Find more information about non-native species at nonnativespecies.org (GB) and invasivespeciesni.co.uk (NI), including:

• Information on non-native species
• ID sheets for over 60 species
• More guidance on preventing the spread of invasive plants
• Information on volunteering to help manage invasive plants in the wild

How to use this guide 

Choose the plants in this booklet to help prevent future invasions.

The plants you choose will often reflect what you want them to do – for example, provide oxygen or cover for fish, hide pond liners or aquaria pumps, or add a splash of colour to pond margins. This booklet provides examples of plants can do the same, or similar, ‘jobs’ as invasive plants and can be used in their place. Some of the plants we suggest may be available only in the peak season from May until September. We appreciate that this may not be ideal for your needs, but if you are able to wait you can help to protect our environment.

Each section includes an example of a damaging invasive non-native plant that should be avoided.

Did you know that it’s against the law to share or sell some garden and pond plants? Find more information at nonnativespecies.org (GB)
and invasivespeciesni.co.uk (NI)

Caring for your pond or aquarium

Know what you grow: Choose the right plants for your garden, pond, aquarium and water features.

• Research plants before you buy them to make sure they are suitable for your needs, easy to dispose of, and won't be invasive. Keep aquarium 
  plants out of your pond.
• Consider native plants or choose non-invasive alternatives. If your pond is near a wetland or waterbody avoid using any plants which aren’t native to the local area. 
• Take care before giving or accepting cuttings, as you may accidentally pass on invasive plants, pests or plant diseases. 

Stop the spread: Keep your plants in your pond and aquarium, don't plant them, or allow them to grow, in the wild.

• Locate your pond away from natural waterbodies and drains to stop plants spreading into the wild.
• When you buy a new plant, remove the surface layer of compost and wash the plant in a bucket before positioning it your pond to remove any seeds or unwanted plant fragments. 
• Use this, and any waste water from your pond or aquarium, on your lawn or to water the plants in your garden, in areas that are a good distance from waterbodies or drains that flow into them.

Compost with care: Dispose of your unwanted plants, roots, weeds, seeds, and water responsibly.

• Make sure nothing you remove from your pond or aquarium gets into the wild, you could be breaking the law if it does.
• Use unwanted aquatic plants as mulch in dry borders in your garden, away from waterbodies or drains.
• Leave any plants you’ve removed on the edge of the pond to drain for a few hours before disposing of them, to allow any wildlife to return to the water.

Find out more about disposing of plants safely at nonnativespecies.org/beplantwise. 

Help to prevent future invasions

You can help to prevent future invasions simply by reporting plants which are spreading in your garden and proving hard to control.

Do you have a plant in your garden that is spreading and proving hard to control? Submit your records at www.plantalert.org to help scientists 
identify which species are likely to become a problem in the wild in the future. If you think you’ve spotted an invasive plant in the wild, you can report it online through iRecord. Find out more at nonnativespecies.org/recording (GB) and invasivespeciesni.co.uk/report-sighting (NI).

Guide to plants

Plants for pond edges

Avoid this invasive non-native species: Water primrose, Ludwigia grandiflora

Originally introduced as an ornamental pond plant, but a number of wild populations have been recorded since 1998. Water primrose quickly covers water bodies restricting recreational use and harming native wildlife. If it were to establish widely in GB control costs could be millions of pounds annually.

Help prevent future invasions by choosing one of the following plants:

Plants for ponds and bog gardens

Avoid this invasive non-native species: American skunk cabbage, Lysichiton americanus

Widely planted in bog gardens, first reported in the wild in 1947. American skunk-cabbage threatens other species in important wet woodland habitats and has a strong odour. 

Help prevent future invasions by choosing one of the following plants.

Floating plants

Avoid this invasive non-native species: Floating pennywort, Hydrocotyle ranunculoides

Introduced as an ornamental pond plant, but has since spread into the wild and become widely established in parts of the UK. Floating pennywort can grow up to 20 cm a day under the right conditions, quickly covering whole waterbodies where it replaces native plants, interferes with recreational activities and can increase the flood risk. 

Help prevent future invasions by choosing one of the following plants.

This list is based on a previous list developed by the RHS and Plantlife, published in 2010, and was updated in 2021 by the Plant Alert Team at Coventry University.

Other titles in this series:

• Gardening without harmful invasive plants
• Landscaping without harmful invasive plants

The list includes only ornamental plants where evidence is available providing some assurance that future invasions from these species are less likely. Coventry University have checked that these plants have not been frequently found outside gardens, or have been recorded as invasive in other countries. The list does not include any species identified in scientific horizon scanning activities designed to identify potential future invasive species. Furthermore, recently introduced ornamental plants or plants not widely available in the trade were not included as there is not enough evidence to assess their potential to escape from cultivation. Both species which have remained on the list, and any species replacing excluded species from the previous list, have been selected according to these criteria. 

Acknowledgements

This booklet was developed with funding from nine water companies through the Aquatic Biosecurity Partnership. The booklet was adapted from a previous version produced by Plantlife and the Royal Horticultural Society, with funding from Defra, NatureScot, and the Esmee Fairbairn Foundation.