Pest plants, or weeds, have attributes that enable them to out-complete other species. They may produce prolific amounts of seed, spread vegetatively, grow rapidly and are often unpalatable to livestock or wildlife. These characteristics allow them to dominate some sites and displace many indigenous plants, contributing to a severe decline in biodiversity and loss of agricultural productivity.
Under the Victorian Catchment and Land Protection (CaLP) Act 1994 certain pest plants are classified as noxious weeds. Land Managers have responsibilities to control these weeds. Failure to do so could result in prosecution and severe fines. Environmental weeds are plant species that are particularly invasive in natural bushland areas, completing with or choking out native plant species. Not all environmental weeds are listed as noxious weeds on the CaLP Act.