Environmental weeds reduce the diversity and/or abundance of native species or adversely affect the function of natural ecosystems. They can do this by forming dense stands that shade and smother native species or by altering natural disturbance regimes such as fire frequency. This can have profound effects on the structure and diversity of vegetation communities.
In addition, weed infestations can reduce the aesthetic appeal of our natural environment for public recreation and appreciation, and invade neighbouring properties where they may reduce agricultural production. Unlike native plants, introduced weeds have no natural predators or diseases in their new environment.
Most of the state's environmental weeds were initially introduced as garden plants. In some cases, their seeds were dispersed across the landscape by birds, animals or the wind. In other cases they have escaped out of gardens or spread into bushland areas from dumped garden waste.
The Office of Environment and Hertiage offers descriptions of major weeds in NSW and a broad range of weed management and information links and resources on their website.