This section provides links to guidance documents that have been produced by a range of organisations. While this information should be a useful resource, the Non-native Species Secretariat cannot endorse any guidance. If you would like to recommend management information to include here please contact us.
On this page:
- General guidance on managing aquatic plants
- Azolla filiculoides (water fern)
- Crassula helmsii (Australian Swamp-stonecrop)
- Hydrocotyle ranunculoides (floating pennywort)
- Lagarosiphon major (curly waterweed)
- Ludwigia grandiflora (water primrose)
- Myriophyllum aquaticum (parrot's feather)
General guidance on managing aquatic plants
Invasive non-native aquatic plants are a particular problem. They can spread rapidly, choke waterways, increase flooding risk and damage angling interests. Many infestations result from people removing plants that have out-grown their ponds and dumping them in nearby waterways. Below are general resources on non-native aquatic plants:
- The Be Plant Wise campaign aims to inform gardeners about invasive non-native species, how to 'know what you grow' and 'compost with care'.
- Managing invasive non-native plants in or near fresh water (PDF) - Environment Agency 2010
- Invasive alien plants in aquatic environments (PDF) - ONEMA The French National Agency for Water and Aquatic Environments 2015
Azolla filiculoides (water fern)
- Information Sheet 22: Azolla filiculoides - Water Fern (PDF). Centre for Ecology & Hydrology (CEH) 2004
- Water fern - Azolla filiculoides (PDF) - Angling Trust
- Water Fern - Azolla filiculoides (external link) - Invasive Species Ireland website (March 2014)
- Kelly, J. & Maguire, C.M. (2009) Azolla filiculoides Invasive Species Action Plan (PDF). Prepared for NIEA and NPWS as part of Invasive Species Ireland
- Water fern, Azolla filiculoides - Under biological control in Ireland (PDF). Case Study 4. Invasive Species Ireland (2008)
- Invasive Alien Species Fact Sheet: Azolla filiculoides (external link) - NOBANIS
- Azolla filiculoides, water fern (external link) - Invasive Alien Species in Northern Ireland website (March 2014)
- Hill, M.P. & Cilliers, C.J. (1999) Azolla filiculoides Lamarck (Pteridophyta: Azollaceae), its status in South Africa and control (external link). Hydrobiologia, 415: 203-206
- Water Fern (Azolla filiculoides) Fact Sheet (PDF) - Sussex Wildlife Trust
- Invasive Species Compendium: Azolla filiculoides (Water Fern) (external link) - CABI website (March 2014)
- Azolla. Integrated control approaches (PDF) - Tasmania Department of Primary Industries, Water and Environment.
- Gassmann, A., Cock, M.J.W., Shaw, R. & Evans, H.C.(2006) The potential for biological control of invasive alien aquatic weeds in Europe: a review (external link). Hydrobiologia, 570(1): 217-222
Crassula helmsii (Australian Swamp-stonecrop)
- Good practice management guidance for Australian swamp stonecrop (PDF) - RAPID LIFE (2018)
- Bridge T. (2005) Controlling New Zealand pygmyweed Crassula helmsii using hot foam, herbicide and by burying at Old Moor RSPB Reserve, South Yorkshire, England (PDF). Conservation Evidence 2, 33-34
- Charlton P.E., Gurney M. & Lyons G. (2010) Large-scale eradication of New Zealand pygmy weed Crassula helmsii from grazing marsh by inundation with seawater, Old Hall Marshes RSPB reserve, Essex,England (PDF). Conservation Evidence 7, 130-133
- Gomes B. (2005) Controlling New Zealand pygmyweed Crassula helmsii in field ditches and a gravel pit by herbicide spraying at Dungeness RSPB Reserve, Kent, England (PDF). Conservation Evidence 2, 62
- Wilton-Jones G. (2005) Control of New Zealand pygmyweed Crassula helmsii by covering with black polythene at The Lodge RSPB Reserve, Bedfordshire, England (PDF). Conservation Evidence 2, 63
- Australian Swamp Stonecrop/New Zealand Pigmyweed (Crassula helmsii) fact sheet (PDF) - Sussex Wildlife Trust
- Dawson, F.H. (1996) Crassula helmsii: attempts at elimination using herbicides (external link). Management and Ecology of Freshwater Plants - Developments in Hydrobiology, 120: 241-245
- Invasive Species Compendium: Crassula helmsii (Australian swamp stonecrop) (external link) - CABI website (11 March 2014)
- Managing invasive non-native plants in or near fresh water (PDF) - Environment Agency 2010
- Pond Check Information & Managment: New Zealand Pigmyweed (Crassula helmsii) (PDF) - The Environmental Records Centre for Cornwall and the Isles of Scilly (ERCCIS) (downloaded from website March 2014)
- Australian swamp-stonecrop - Crassula helmsii (PDF) - Angling Trust
- Gassmann, A., Cock, M.J.W., Shaw, R. & Evans, H.C.(2006) The potential for biological control of invasive alien aquatic weeds in Europe: a review (external link). Hydrobiologia, 570(1): 217-222
PLEASE NOTE: the following links have been identified as having outdated information on the use of dichlobenil, which is no longer allowed for use in the UK
- Centre for Ecology and Hydrology (CEH) information sheet on Crassula helmsii (Australian Swamp-stonecrop (external link)
- Controlling New Zealand pygmyweed (Crassula helmsii) (PDF) - Suffolk Wildlife Trust
- New Zealand Pigmyweed (Crassula helmsii) Invasive Species Action Plan (2009) - Invasive Species Ireland
- Data sheets on quarantine pests: Crassula helmsii (PDF) - EPPO (downloaded from website March 2014)
- Nault, M.E. and Mikulyuk, A. (2011) Australian Swamp Stonecrop (Crassula helmsii): A Technical Review of Distribution, Ecology, Impacts, and Management (PDF). Wisconsin Department of Natural Resources Bureau of Science Services, UB-SS-1078 2011. Madison, Wisconsin, USA
- ECUS (2013) Control of New Zealand pygmyweed (Crassula helmsii) at Mochrum Lochs SSSI, phase I, 2007-2008 (PDF).Scottish Natural Heritage Commissioned Report No.483
Hydrocotyle ranunculoides (floating pennywort)
GB Floating Pennywort Strategy
The following guidance and case studies on floating pennywort management have been developed through the GB Floating Pennywort Strategy, agreed by a national partnership between government and non-government organisations to facilitate local groups engaged in floating management. Find out more and get involved.
- 10 stage approach to floating pennywort management
- Case study: Yorkshire
- Case study: RDAA / Lower Kennet
- Case study: Peak Forest Canal
- Case study: River Stort (PDF)
Other resources
- Public Pennywort Guide Draft 1 (keepbritaintidy.org) - Keep Britain Tidy (2023)
- Good practice management guidance for floating pennywort (PDF) - RAPID LIFE (2018)
- Information Sheet: Control of Floating Pennywort (Hydrocotyle ranunculoides) (PDF) - Centre for Ecology & Hydrology (CEH) 2010
- Floating Pennywort - Hydrocotyle ranunculoides (PDF) - Angling Trust
- Invasive Species Compendium: Hydrocotyle ranunculoides (floating pennywort) - CABI website (March 2014)
- Invasive Alien Species Fact Sheet: Hydrocotyle ranunculoides (PDF) - NOBANIS (2012)
- Managing invasive non-native plants in or near fresh water (PDF) - Environment Agency 2010
- Hydrocotyle ranunculoides L.f. A guide to Identification, Risk Assessment and Management (PDF). Plant Protection Service, Wageningen, NL and Centre for Ecology and Hydrology, Wallingford, UK (2011)
- Newman, J.R. & Dawson, F.H. (1999) Ecology, distribution and chemical control of Hydrocotyle ranunculoides in the U.K.(external link) Hydrobiologia, 415: 295-298
- Ruiz-Avila, R.J. & Klemm, V.V. (1996) Management of Hydrocotyle ranunculoides L.f., an aquatic invasive weed of urban waterways in Western Australia (external link) Hydrobiologia, 340(1-3): 187-190
- Kelly, A. (2006) Removal of invasive floating pennywort Hydrocotyle ranunculoides from Gillingham Marshes, Suffolk, England (PDF). Conservation Evidence, 3: 52-53
- Gassmann, A., Cock, M.J.W., Shaw, R. & Evans, H.C. (2006) The potential for biological control of invasive alien aquatic weeds in Europe: a review. Hydrobiologia, 570(1): 217-222
Lagarosiphon major (curly waterweed)
- Good practice management guidance for curly waterweed (PDF) - RAPID LIFE (2018)
Ludwigia grandiflora (water primrose)
- Good practice management guidance for water primrose (PDF) - RAPID LIFE (2018)
- Ludwigia guide for Landowners (working draft) (PDF) - Trevor Renals, Environment Agency
- Defra funded report: Eradication strategies for invasive non-native Ludwigia species - PH0422 (external link)
- Management options for Water Primrose Ludwigia grandiflora (PDF) - Angling Trust
- Cattail and Water Primrose Control in Missouri Lakes and Ponds (PDF) - Missouri Department of Conservation
- Invasive Species Compendium: Ludwigia grandiflora (water primrose) (external link) - CABI website (11 March 2014)
- Managing invasive non-native plants in or near fresh water (PDF) - Environment Agency 2010
- Pond Check Information & Management: Creeping Water Primrose (Ludwigia peploides/hexaploides/grandiflora) (PDF) - The Environmental Records Centre for Cornwall and the Isles of Scilly (ERCCIS) (downloaded from website March 2014)
- Gassmann, A., Cock, M.J.W., Shaw, R. & Evans, H.C.(2006) The potential for biological control of invasive alien aquatic weeds in Europe: a review (external link). Hydrobiologia, 570(1): 217-222
Myriophyllum aquaticum (parrot's feather)
- Good practice management guidance for Parrot's feather (PDF) - RAPID LIFE (2018)
- Managing invasive non-native plants in or near fresh water (PDF) - Environment Agency 2010
- Information Sheet: Myriophyllum aquaticum Parrot's Feather (PDF) - Centre for Ecology & Hydrology (CEH) 2004
- Invasive Species Compendium: Myriophyllum aquaticum (Parrot-feather) (external link) - CABI website (March 2014)
- Parrot's feather weed - Myriophyllum aquaticum (PDF) - Angling Trust
- Kelly, J. & Maguire, C.M. (2009) Parrots Feather (Myriophyllum aquaticum) Invasive Species Action Plan (PDF). Prepared for NIEA and NPWS as part of Invasive Species Ireland.
- Myriophyllum aquaticum (Vell.) Verdcourt. A guide to Identification, Risk Assessment and Management (PDF) . Plant Protection Service, Wageningen, NL and Centre for Ecology and Hydrology, Wallingford, UK (2011)
- EPPO data sheet on Invasive Plants: Myriophyllum aquaticum (PDF) (draft) - EPPO (downloaded from website March 2014)
- Parrots Feather (Myriophyllum aquaticum) Fact Sheet (PDF) - Sussex Wildlife Trust
- Non-native Invasive Freshwater Plants: Parrots feather (Myriophyllum aquaticum) (external link) - Washington State Department of Ecology website (March 2014)
- Campbell, P. (2008) Parrots feather, Myriophyllum aquaticum (PDF)
- Wersal, R.M. & Madsen, J.D. (2010) Comparison of Subsurface and Foliar Herbicide Applications for Control of Parrotfeather (Myriophyllum aquaticum) (external link). Invasive Plant Science and Management 3(3): 262-267
- Madsen, J.D. & Wersal, R. Parrotfeather [Myriophyllum aquaticum (Vellozo) Verdecourt] (PDF). Mississippi State University Geosystems Research Institute
- Wersal, R.M. & Madsen, J.D. (2007) Comparison of Imazapyr and Imazamox for Control of Parrotfeather (Myriophyllum aquaticum (Vell.) Verdc.) (PDF). J. Aquat. Plant Manage. 45: 132-136