Salix sp except S. babylonica, S. x reichardtii, S. x calodendron
Other Common Names:
All Of N.S.W.
The requirements in the Noxious Weeds Act 1993 for a notifiable weed must be complied with.
Some willow species are declared Class 2 or 3 with strict control measures in place. Other species, such as weeping willow, are not declared noxious and have no enforceable control measures.
Why Is It Bad?:
Willows invade waterways and wetlands throughout south eastern Australia. Willows alter water courses by increasing sediment and reducing light penetration and water temperatures, impacting on aquatic life. Infestations eliminate virtually all indigenous vegetation from the site. Willows are mostly spread vegetatively as broken off branches or twigs can regrow at any time of year.
Willows are Weeds of National Significance (WoNS) due to their invasiveness, potential for spread, and impacts on the environment and economy.
Leaves are mostly lanceolate, green on upper surface and light underneath, with serrated edges.
Flowers are formed in long catkins which are either male or female. Flowering does not occur until a plant is 3-8 years old.
Seeds are tiny (less than 1mm) and will germinate very quickly if they land on damp soil. They are short lived, remaining viable for only 1-2 weeks. Seeds are easily spread by wind and water up to 100km from the parent plant.
Willow roots will form large dense mats on the surface of the soil or within the watercourse.
Small plants (less than 0.5m) can be easily hand pulled but should be disposed of responsibly to avoid spread. Larger plants should be killed with herbicide treatment before being removed. Attempts to remove living trees will result in further spread as broken branches and twigs are easily dispersed by heavy machinery.
Foliar spray, stem injection and basal bark are the methods most commonly recommended. Please refer to the Noxious & Environmental Weed Control Handbook or your friendly local weeds officer for more information. Integrated weed management is recommended for successful control.
Slashing & Cutting:
Willow sawfly is widespread across NSW. It was not deliberately introduced to Australia so therefore did not undergo normal research procedures. It is commonly found in other countries but it is still unclear how it arrived in Australia.
Willow sawfly is capable of defoliating adult plants if populations of larvae are high enough. However, it should not be relied upon as a sole source of control.