Tall Knotweed - profile

Indicative distribution

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Key:

known

predicted

The areas shown in pink and/purple are the sub-regions where the species or community is known or predicted to occur. They may not occur thoughout the sub-region but may be restricted to certain areas. ( click here to see geographic restrictions). The information presented in this map is only indicative and may contain errors and omissions.

Scientific name: Persicaria elatior

Conservation status in NSW: Vulnerable

Commonwealth status: Vulnerable

Profile last updated: 11 Oct 2022

Description

Tall Knotweed is an erect herb 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 its plant family. Its tiny flowers are in long, narrow spikes to 5 cm long. The pink flower-segments are less than 4 mm long.

Distribution

Tall Knotweed has been recorded in south-eastern NSW (Mt Dromedary (an old record), Moruya State Forest near Turlinjah, the Upper Avon River catchment north of Robertson, Bermagui, and Picton Lakes. In northern NSW it is known from Raymond Terrace (near Newcastle) and the Grafton area (Cherry Tree and Gibberagee State Forests). The species also occurs in Queensland.

Habitat and ecology

This species normally grows in damp places, especially beside streams and lakes. Occasionally in swamp forest or associated with disturbance.

Regional distribution and habitat

Click on a region below to view detailed distribution, habitat and vegetation information.

Threats

Clearing or disturbance of moist habitat
Damage to road and track populations through maintenance activities
Clearing of or hydrological changes to wetland vegetation.
The species is susceptible to extinction via stochastic processes due to its small known population size and restricted distribution.
Ludwigia longifolia and Solanum nigrum. Potential for Buffalo grass at Wanda to further invade down to waters edge.
Grazers eating the plant and reducing the ability to flower and set seed. Trampling may also damage seedbank.

Recovery strategies

Priority actions are the specific, practical things that must be done to recover a threatened species, population or ecological community. The Office of Environment and Heritage has identified 1 priority actions to help recover the Tall Knotweed in New South Wales.

Activities to assist this species

Provide information to landholders in areas likely to contain this species to enable them to identify it.
Ensure that adequate survey is done for this species in development and clearing proposals in suitable habitat within its range.
Alert road and track maintenance staff (in Sydney Water and State Forests) to its occurrence to ensure that populations are not inadvertently damaged.
Protect wetland habitat containing (or likely to contain) this species.

Information sources

Harden, G.J. (ed.) (2000) Flora of New South Wales Vol. 1. UNSW Press, Kensington, NSW.

IBRA Bioregion	IBRA Subregion	Known or predicted	Geographic restrictions region

NSW North Coast	Karuah Manning	Known	None
South East Corner	Bateman	Known	None
South East Corner	South East Coastal Ranges	Known	None
South Eastern Queensland	Clarence Lowlands	Known	None
South Eastern Queensland	Woodenbong	Known	None
Sydney Basin	Burragorang	Known	None
Sydney Basin	Cumberland	Known	None
Sydney Basin	Hunter	Known	None
Sydney Basin	Moss Vale	Known	None
Sydney Basin	Wyong	Known	None
Sydney Basin	Yengo	Known	None

Images

Flowers, Tall Knotweed Image 1 of 2.
View slideshow.

Related information

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