What are Invasive Weeds?

Weeds are plant species that spread and persist in areas in which they did not previously exist. Many weed species are introduced, however native species can also become weeds if the level of invasion causes negative economic, environmental or human health impacts above a tolerable level. Nationally exotic species account for approximately 15% of all flora.

Why are Weeds an Issue?

Typical weed characteristics including fast growth, rapid reproduction, high dispersal ability and wide tolerance to environmental conditions, meaning that they’re able to invade and quickly overtake sites (1). The Transport of invasive species into new areas is achieved via wind, waterways, people, vehicles, machinery, bird and other animals (2). Once introduced at a site, invasive weeds compete with native plants for space, nutrients and sunlight, risking the integrity of the environment, the economy and human health (3).

1. Dekker, J. Evolutionary Ecology of Weeds. Iowa State University. 2011. Available from: 

2. Van der MeulenAW, Sindel, BM. Identifying and exploring pathways of weed spread within Australia: a literature review. University of New England. 2008. Available from:,-Appendix-3.pdf

3. Williams J, West C. Environmental weeds in Australia and New Zealand: Issues and approaches to management. Austral Ecology. 2000; 25(5). Available from:

What is the Distribution and Abundance of Common Weed Species in Australia?

Due to their high dispersal ability and wide environmental tolerances, weeds take advantage of space that is created after a disturbances e.g. clearing, trampling and burning etc. High weed abundance would be expected along trails, roads and waterways where there may be frequent disturbance. The invasion of weeds into a site may be sudden and therefore difficult to track the exact extent of the issue. To help reduce the spread it is necessary to report the presence of weeds as soon as possible so appropriate management action can be undertaken, this can be done by individuals via MyWeedWatcher application. The Environmental Protection Authority published the State of Environment Report 2007 providing formal documentation on the distribution and abundance of major weed species in WA.

How Does Weed Management Differ Between Rural and urban areas?

Weed management in urban areas may require more planning and maintenance due to the higher levels of disturbance, such as the use of tracks, roads and trails, trampling and dumping of rubbish. The use of herbicides in certain areas, for example schools, can invoke a level of community concern. In these cases, the use of pesticides should be restricted to areas that are not going to impact people or the environment, and instead manual, non-chemical methods should be employed. Guidelines and strategies for the prevention and control of weeds at each management level have been provided in Who Manages Invasive Weeds in Western Australia?



Private Land Owners

Landowners are responsible for the management of weeds on their property and should take a proactive effort to ensure they do not spread to neighboring properties.

Prevention is the most effective method of dealing with weeds. Weed Identification Databases can help improve knowledge and identification skills of common weeds. There are many resources available that provide advice on planting native alternatives, such as the Grow Me Instead Guide for Western Australian gardens.

Local councils or community groups may provide resources for planting alternative in your area:

Community Groups

The roles of community groups are to raise awareness about the potential of weeds to create environmental, economic and social issues, coordinate weed management at a local level as well as having the opportunity for creating links over a regional scale.

The following resources may provide help in dealing with weeds:

  • The spread of weeds can occur through any activity in the bush, including weeding and revegetation. The Arrive Clean, Leave Clean Guidelines can help prevent the spread of invasive plants in local bushlands.
  • The Parks and Wildlife Services weed resource link provides useful documents on weed policies, issues, research and management strategies.
  • A smartphone application, MyWeedWatcher, can be used to identify and report weeds in an area.

Local Councils

Local councils are responsible for managing weeds on public land as well as providing information, coordination and support to community groups. Different methods of weed management can be undertaken, including biological, cultural, physical or chemical techniques. In many cases an integrated approaching using a range of the above controls may be the best solution.

While not always essential or practical, chemical control can offer a cost-effective method of managing weeds. It is important to be able to understand the labeling and correct application methods to avoid impacts on people and the environment. Guidelinesand information on application methods have been prepared for land managers to ensure safe application of herbicides.

Examples of local councils with feral weed management plans are listed below:

City of Joondalup Weed Management Plan

City of Melville Environmental Weed Management Guidelines

Shire of Mundaring Weed Control Strategy 

It may be useful to provide a document for residents that suggests native alternatives to plant in their garden such as the one prepared by Shire of Kalamunda.

State Government

The WA State Government is responsible for managing the spread and control of weeds on public land. The State coordinates these efforts through legislating the responsibilities of land managers and through providing funding and resources.

The State Weed Plan has been developed using valuable information from government departments, networks and groups. Other relevant resources may include:

  • The Australian Weeds Strategy, which provides guidance on preventing weed establishment, reducing the impacts and strategies to enhance the capacity and commitment to solve the weed problem in Australia.
  • The first step in controlling weeds is to understand the ecology of the plant. The Australian Government has compiled a list of Weeds of National Significance, which provides background information, dispersal strategies and environmental tolerances. Photographs are provided to help identify the weed.