What is a weed? Simply, a weed is defined as a plant growing where you don't want it. However, in reality it is a bit more complicated than that. In NSW there are many other definitions for weeds too. You may have heard of environmental weeds, agricultural weeds, Weeds of National Significance (WoNS) and National Environmental Alert List weeds.
These are all different classifications of weeds and interestingly some weeds can be several of these classifications. For instance, serrated tussock is a WoNS and a serious agricultural weed in some parts of NSW. Similarly, alligator weed is a WoNS, an environmental weed and is now emerging as an agricultural weed as well.
You can check what weeds are in your area and how they need to be managed using NSW WeedWise.
In NSW 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.
Under the National Weeds Strategy, 32 introduced plants have been identified as Weeds of National Significance (WONS). A list of 20 was endorsed in 1999 and a further 12 were added in 2012.
These weeds are regarded as the worst weeds in Australia because of their invasiveness, potential for spread, and economic and environmental impacts.
Under the National Weeds Strategy, 28 environmental weeds were identified National Environmental Alert Weeds. Alert Weeds are non-native plant species that are in the early stages of establishment and have the potential to become a significant threat to biodiversity if they are not managed.
Freshwater ecosystems are highly vulnerable to invasion by weeds. Many exotic plants have been accidentally or deliberately introduced into waterways in New South Wales, and have become widespread.
Some Australian native plants have become invasive in areas beyond their natural range or habitat. This is partly due to their popularity as ornamental plants, and partly due to landscape changes.
Many areas of native vegetation are protected in Australia. Always check native vegetation requirements before undertaking control of a weedy native plant.