Black willow is an invasive tree of rivers, streams and wetlands. It is considered one of the most serious weeds of riparian and wetland ecosystems in Australia. It is a Weed of National Significance.
This weed belongs to the group Willows
This plant is a Weed of National Significance
This plant must not be sold anywhere in NSW
Black willow is an invasive woody weed of rivers, streams and wetlands throughout temperate Australia. It is considered one of the most serious weeds of riparian and wetland ecosystems in Australia, where it spreads quickly and forms dense stands along water courses.
Black willows were originally planted during the 1960s for soil stabilisation projects along streams and river banks in Victoria and southern NSW. They are now considered to cause erosion and flooding, and reduce water availability and quality.
Black willow is an upright deciduous tree that stands up to 20 m high, usually with one trunk but able to have up to 4 main stems. Young trees have a conical shape which broadens with age. Male and female trees are equally common.
Black willow is native to eastern Canada, and eastern and central USA, particularly along the Mississippi River. In its native range it can form large stands and has commercial importance. Black willow does not appear to be a problematic weed in any other part of the world.
In NSW, the largest infestations of black willow occur in the Hawkesbury-Nepean and Murrumbidgee catchments, which are subject to ongoing control and monitoring programs. Black willow has the potential to invade rivers, streams and wetland areas throughout NSW.
Black willow spreads mostly from seed but can also grow from broken stems. A female tree produces thousands of light fluffy seeds each year that can travel by wind or water. Seeds will only survive for a couple of weeks, yet under ideal conditions (bare wet ground in full sunlight) germination is fast and a mass of seedlings may be seen in about a month.
Stem fragments may break off and travel many kilometers downstream. New roots will grow in water from these fragments, resulting in new infestations.
Black willow is able to hybridise (cross-pollinate) and breed with other willow species. This may increase problems caused by other Salix species.
Black willows prefer open sunny positions and will grow along the banks of streams, rivers, lagoons and swamps, spreading their roots out into the water. Once established they can spread further into a water course, taking up large amounts of water, and eventually diverting the natural flow.
Reviewed by: Michael Michelmore; Edited by: Elissa van Oosterhout
Holland Clift, S and Davies, J (2007). Willows National Management Guide: current management and control options for willows (Salix spp.) in Australia. Victorian Department of Primary Industries, Geelong.
Jacobs, SWL and Murray, L (2000). Salix nigra spp., in PlantNET - The Plant Information Network System of The Royal Botanic Gardens and Domain Trust, Sydney, Australia. Available at http://plantnet.rbgsyd.nsw.gov.au
A local council weeds officer will assist with identification, control information, removal and eradication. Very few herbicides are registered for use near water and extreme care must be taken to avoid contact with any non-target species.
See Using herbicides for more information.
Glyphosate 360 g/L
(Various products)
Rate: 1.0–1.3 L in 100 L of water
Comments: Spray to wet all foliage. Use the higher rate for trees 1–2 m high.
Withholding period: Nil.
Herbicide group: M, Inhibitors of EPSP synthase
Resistance risk: Moderate
Glyphosate 360 g/L
(Various products)
Rate: Undiluted
Comments: Stem injection.
Withholding period: Nil.
Herbicide group: M, Inhibitors of EPSP synthase
Resistance risk: Moderate
Picloram 44.7 g/kg + Aminopyralid 4.47 g/L
(Vigilant II ®)
Rate: Undiluted
Comments: Cut stump/stem injection application. Apply a 3–5 mm layer of gel for stems less than 20 mm. Apply 5 mm layer on stems above 20 mm .
Withholding period: Nil.
Herbicide group: I, Disruptors of plant cell growth (synthetic auxins)
Resistance risk: Moderate
Triclopyr 240 g/L + Picloram 120 g/L
(Access™ )
Rate: 1.0 L per 15 L of diesel
Comments: Cut stump application method, for plants in excess of 5cm basal diameter
Withholding period: Nil
Herbicide group: I, Disruptors of plant cell growth (synthetic auxins)
Resistance risk: Moderate
The content provided here is for information purposes only and is taken from the Biosecurity Act 2015 and its subordinate legislation, and the Regional Strategic Weed Management Plans (published by each Local Land Services region in NSW). It describes the state and regional priorities for weeds in New South Wales, Australia.
Area | Duty |
---|---|
All of NSW | General Biosecurity Duty All plants are regulated with a general biosecurity duty to prevent, eliminate or minimise any biosecurity risk they may pose. Any person who deals with any plant, who knows (or ought to know) of any biosecurity risk, has a duty to ensure the risk is prevented, eliminated or minimised, so far as is reasonably practicable. |
All of NSW |
Prohibition on dealings
Must not be imported into the State or sold |
Greater Sydney |
Regional Recommended Measure*
Land managers should mitigate the risk of new weeds being introduced to their land. The plant should be eradicated from the land and the land kept free of the plant. The plant should not be bought, sold, grown, carried or released into the environment. Notify local control authority if found. |
Greater Sydney |
Regional Recommended Measure*
The plant should be eradicated from the land and the land kept free of the plant. The plant should not be bought, sold, grown, carried or released into the environment. Notify local control authority if found. |
Murray |
Regional Recommended Measure*
Land managers should mitigate the risk of new weeds being introduced to their land. The plant should be eradicated from the land and the land kept free of the plant. The plant should not be bought, sold, grown, carried or released into the environment. Notify local control authority if found. |
North Coast
Exclusion zone: all lands in the region, except the core infestation area of: Clarence Valley Council and Nambucca Valley Shire Council |
Regional Recommended Measure*
Exclusion zone: The plant should be eradicated from the land and the land kept free of the plant. Land managers should mitigate the risk of the plant being introduced to their land. Core infestation area: Land managers reduce impacts from the plant on priority assets. |
North West |
Regional Recommended Measure*
Land managers should mitigate the risk of new weeds being introduced to their land. Land managers should mitigate spread from their land. |
Riverina |
Regional Recommended Measure*
Land managers should mitigate the risk of the plant being introduced to their land. The plant should be eradicated from the land and the land kept free of the plant. |
*To see the Regional Strategic Weeds Management Plans containing demonstrated outcomes that fulfil the general biosecurity duty for this weed click here |
Reviewed 2018