Species Profile and Threats Database

For information to assist proponents in referral, environmental assessments and compliance issues, refer to the Policy Statements and Guidelines (where available), the Conservation Advice (where available) or the Listing Advice (where available).
In addition, proponents and land managers should refer to the Recovery Plan (where available) or the Conservation Advice (where available) for recovery, mitigation and conservation information.

EPBC Act Listing Status Listed as Vulnerable as Persicaria elatior
Listing and Conservation Advices Commonwealth Conservation Advice on Persicaria elatior (Threatened Species Scientific Committee (TSSC), 2008aba) [Conservation Advice].
Recovery Plan Decision Recovery Plan not required, included on the Not Commenced List (1/11/2009).
Adopted/Made Recovery Plans
Federal Register of
    Legislative Instruments
Declaration under s178, s181, and s183 of the Environment Protection and Biodiversity Conservation Act 1999 - List of threatened species, List of threatened ecological communities and List of threatening processes (Commonwealth of Australia, 2000) [Legislative Instrument] as Persicaria elatior.
State Government
    Documents and Websites
NSW:Tall Knotweed - profile (NSW Department of Environment, Climate Change and Water (NSW DECCW), 2005ik) [Internet].
State Listing Status
NSW: Listed as Vulnerable (Threatened Species Conservation Act 1995 (New South Wales): December 2013 list) as Persicaria elatior
QLD: Listed as Vulnerable (Nature Conservation Act 1992 (Queensland): May 2014 list) as Persicaria elatior
Scientific name Persicaria elatior [5831]
Family Polygonaceae:Polygonales:Magnoliopsida:Magnoliophyta:Plantae
Species author (R.Br.) Sojak
Infraspecies author  
Reference Preslia 46 (1974) 153.
Other names Polygonum elatius [23199]
Distribution map Species Distribution Map

This is an indicative distribution map of the present distribution of the species based on best available knowledge. See map caveat for more information.

Illustrations Google Images

Scientific name: Persicaria elatior

Common name: Knotweed

Knotweed is an erect herb growing to 90 cm tall, with stalked, glandular hairs (i.e. they are knobbed when seen under a lens) on most plant parts. Its leaves are up to 11 cm long and 30 mm wide. A sheath encircles the stem at the base of each leaf, which is characteristic of the Polygonaceae family. Its tiny flowers are in long, narrow spikes up to 5 cm long. The pink flower-segments are less than 4 mm long (NSW DECCW 2005ov).

General distribution

Knotweed is known from the North Coast, Central Coast and South Coast Botanical Subdivisions in New South Wales (NSW) and Moreton Pastoral District in south-east Queensland (NSW undated; Queensland Herbarium 1999). There is a single disjunct record from the Barron River, Mareeba in north-east Queensland, though this record possibly represents a misidentification (Quinn et al. 1995).

New South Wales

Knotweed has been collected from eight sites in NSW including:

South-east NSW

  • Mt Dromedary (an old record) (NSW DECCW 2005ov)
  • Moruya State Forest (SF), near Turlinjah (NSW DECCW 2005ov)
  • the Upper Avon River catchment, north of Robertson (NSW DECCW 2005ov)
  • Bermagui (NSW DECCW 2005ov)
  • Picton Lakes (NSW DECCW 2005ov).

North-east NSW

  • Richmond Range SF, near Casino (Quinn et al. 1995)
  • Raymond Terrace, near Newcastle (NSW DECCW 2005ov)
  • Cherry Tree SF and Gibberagee SF, near Grafton (NSW DECCW 2005ov).


Knotweed has been recorded at seven sites in south-east Queensland:

  • Cornubia Wetland, 2008, 12 specimens at a number of positions (Leiper 2008)
  • "end of Dulwich Street", Loganholme, May 2006 (Leiper 2008)
  • North Stradbroke Island, March 2006 (Leiper 2008)
  • South Stradbroke Island, February 1997 (Queensland Herbarium 1999)
  • North Stradbroke Island, 1938 (Queensland Herbarium 1999)
  • Ekibin Creek, January 1916 (Queensland Herbarium 1999)
  • Eagle Farm, November 1888 (Queensland Herbarium 1999).

At Cornubia Wetland, 12 specimens were recorded (Leiper 2008). Population data is not available for other sites.

General habitat

Knotweed normally grows in damp places, including:

  • coastal with swampy areas (Quinn et al. 1995)
  • along watercourses, streams and lakes (NSW DECCW 2005ov)
  • swamp forest (NSW DECCW 2005ov)
  • disturbed areas (NSW DECCW 2005ov).

Associated species include Melaleuca linearifolia, M. quinquenervia, Lophostemon suaveolens, Casuarina glauca, Corymbia maculata, Pseudognaphalium luteoalbum and Polygonum hydropiper (NSW undated; Quinn et al. 1995).

Specific habitat

On South Stradbroke Island, Knotweed is found in waterholes under Livistona australis (Queensland Herbarium 1999).

At Cornubia Wetland, where 12 specimens have been recorded, there are three different vegetation communities in the area (Leiper 2008). Leiper (2008) is not specific about whether a particular community is preferred. These vegetation communities are (Leiper 2008):

  • Regional Ecosystem 12.9.1; tall open forest on sedimentary derived soils with a mixture of gum species. Species include Eucalyptus crebra, Angophora leiocarpa, Corymbia intermedia and L. confertus.
  • Regional Ecosystem 12.3.8; swamps with Cyperys spp., Schoenoplectus spp. and Eleocharis spp.
  • Regional Ecosystem 12.3.5; M. quinquenervia open forest on coastal alluvium.

Knotweed appears to be a short-lived herbaceous species, surviving for up to two years (Leiper 2008). Following rain, it germinates readily from seed on bare ground. Knotweed grows rapidly, flowers and sets seed within six months of germinating (Leiper 2008). Flowering mostly occurs in summer (Quinn et al. 1995; Stanley & Ross 1983).

At Cornubia Wetland, populations have, following rain, been observed taking advantage of exposed areas of soil (made bare during dry periods) (Leiper 2008). At these sites, it competes with Persicaria attenuata and P. orientalis as well as other herbaceous species such as grasses and sedge (Leiper 2008).

At Cornubia Wetland, evidence of death following dry periods was observed in April to May 2008 (Leiper 2008). Between December 2007 and March 2008, there had been regular rain and specimens had grown quickly and flowered profusely (Leiper 2008). Field surveys in May 2008 observed that many healthy specimens had died after a dry period (Leiper 2008).

Knotweed plants from South Stradbroke Island have been successfully cultivated from seed and this process has been used in revegetation projects on the island (Leiper 2008).

Knotweed is distinguished from Persicaria lapathifolia by having stalked glandular hairs present on most parts of the plant (Wilson 1990).

Identified threats

This species is threatened by:

  • inadvertent clearing of moist disturbed habitat (e.g. mowing or weed spraying) (NSW DECCW 2005ov)
  • habitat depletion from clearing and disturbance for urban development in coastal areas (Quinn et al. 1995)
  • damage to road and track populations through maintenance activities (NSW DECCW 2005ov)
  • clearing or hydrological changes (swamp draining and other activities) to wetland vegetation (NSW DECCW 2005ov).

Threat abatement actions

Actions identified to recover this species include (NSW DECCW 2005ov):

  • Identification of priority locations, assessment of threats and implementation of recovery actions.
  • Provision of information to landholders to assist identification.
  • Ensuring that adequate surveys occur in suitable habitat proposed for development or clearing.
  • Alerting road and track maintenance staff (in Sydney Water and NSW Forests) to reduce damage to populations.
  • Protecting wetland habitat containing (or likely to contain) this species.

Other actions that have been identified include (TSSC 2008aba):

  • Design and implement a monitoring program or, if appropriate, support and enhance existing programs.
  • More precisely assess population size, distribution, ecological requirements and the relative impacts of threatening processes.
  • Undertake survey work in suitable habitat and potential habitat to locate any additional populations.
  • Monitor the progress of recovery, including the effectiveness of management actions and the need to modify them if necessary.
  • Manage changes to hydrology, such as changes to the water table levels, increased run-off, sedimentation or pollution.
  • Manage disruptions to water flows.
  • Minimise adverse impacts from land use at known sites.
  • Investigate further formal conservation arrangements such as the use of covenants, conservation agreements or inclusion in reserve tenure to protect wetland habitat containing Knotweed.
  • Manage any other known, potential or emerging threats.
  • Undertake appropriate seed collection and storage.
  • Investigate options for linking, enhancing or establishing additional populations.
  • Implement national translocation protocols (Vallee et al. 2004) if establishing additional populations is considered necessary and feasible.

Actions undertaken

Cultivation and revegetation projects have been undertaken by staff at Couran Cove Resort, South Stradbroke Island (Leiper 2008).

The following table lists known and perceived threats to this species. Threats are based on the International Union for Conservation of Nature and Natural Resources (IUCN) threat classification version 1.1.

Threat Class Threatening Species References
Biological Resource Use:Logging and Wood Harvesting:Habitat loss, modification and degradation due to timber harvesting Northern Rivers Regional Biodiversity Management Plan (NSW Department of Environment, Climate Change and Water (NSW DECCW), 2010p) [State Recovery Plan].
Natural System Modifications:Dams and Water Management/Use:Alteration of hydrological regimes and water quality Persicaria elatior in Species Profile and Threats (SPRAT) database (Department of the Environment and Heritage (DEH), 2006qm) [Internet].
Northern Rivers Regional Biodiversity Management Plan (NSW Department of Environment, Climate Change and Water (NSW DECCW), 2010p) [State Recovery Plan].
Natural System Modifications:Dams and Water Management/Use:Changes in hydrology including habitat drainage Persicaria elatior in Species Profile and Threats (SPRAT) database (Department of the Environment and Heritage (DEH), 2006qm) [Internet].
Residential and Commercial Development:Housing and Urban Areas:Habitat loss, modification and fragmentation due to urban development Persicaria elatior in Species Profile and Threats (SPRAT) database (Department of the Environment and Heritage (DEH), 2006qm) [Internet].
Transportation and Service Corridors:Roads and Railroads:Development and/or maintenance of roads Commonwealth Conservation Advice on Persicaria elatior (Threatened Species Scientific Committee (TSSC), 2008aba) [Conservation Advice].

Leiper, G. (2008). Appendix 1 - Vegetation Report for Cornubia Wetlands. Fitzpatrick, B., ed. A Biological Survey of the Cornubia Wetland Reserve (2007-2008). Prepared by B. Fitzpatrick for the Logan City Council Environment program. Logan City Council document accession number 4793078.

NSW Department of Environment, Climate Change and Water (NSW DECCW) (2005ov). NSW threatened species - Tall Knotweed - profile. [Online]. Available from:

NSW Herbarium (undated). New South Wales National Herbarium specimens.

Queensland Herbarium (1999). Personal communication.

Quinn, F., J.B. Williams, C.L. Gross & J. Bruhl (1995). Report on rare and threatened plants of north-eastern New South Wales. Armidale: University of New England.

Stanley, T.D. & E.M. Ross (1983). Flora of south-eastern Queensland. Volume One. Brisbane, Queensland: Department of Primary Industries.

Threatened Species Scientific Committee (TSSC) (2008aba). Commonwealth Conservation Advice on Persicaria elatior. [Online]. Department of the Environment, Water, Heritage and the Arts. Available from:

Vallee, L., T. Hogbin, L. Monks, B. Makinson, M. Matthes & M. Rossetto (2004). Guidelines for the translocation of threatened plants in Australia - Second Edition. Canberra, ACT: Australian Network for Plant Conservation.

Wilson KL (1990). Some Widespread Species of Persicaria (Polygonaceae) and Their Allies. Kew Bulletin. 45(4):621-636.

EPBC Act email updates can be received via the Communities for Communities newsletter and the EPBC Act newsletter.

This database is designed to provide statutory, biological and ecological information on species and ecological communities, migratory species, marine species, and species and species products subject to international trade and commercial use protected under the Environment Protection and Biodiversity Conservation Act 1999 (the EPBC Act). It has been compiled from a range of sources including listing advice, recovery plans, published literature and individual experts. While reasonable efforts have been made to ensure the accuracy of the information, no guarantee is given, nor responsibility taken, by the Commonwealth for its accuracy, currency or completeness. The Commonwealth does not accept any responsibility for any loss or damage that may be occasioned directly or indirectly through the use of, or reliance on, the information contained in this database. The information contained in this database does not necessarily represent the views of the Commonwealth. This database is not intended to be a complete source of information on the matters it deals with. Individuals and organisations should consider all the available information, including that available from other sources, in deciding whether there is a need to make a referral or apply for a permit or exemption under the EPBC Act.

Citation: Department of the Environment (2014). Persicaria elatior in Species Profile and Threats Database, Department of the Environment, Canberra. Available from: Accessed Thu, 21 Aug 2014 13:35:59 +1000.