Weed Biosecurity and Control

What is a Weed?

Broadly speaking a ‘weed’ is best defined as a plant growing out of place or where it is not wanted.

Most of the serious weeds in Australia have been introduced from overseas. Plants such as rhus tree can cause serious health problems including asthma, allergies and dermatitis. Blackberry and giant parramatta grass threaten productive agricultural lands, whilst pampas grass, cat’s claw creeper, bitou bush and boneseed, pose a major risk to our natural environment. Aquatic plants such as water hyacinth, salvinia and alligator weed are a major threat to our freshwater wetlands, rivers and storage systems.

Weeds cost the Australian community some $4 billion annually.  Over two-thirds (66%) of our weeds have been introduced legally as attractive garden ornamentals.  Every year at least 12 new species become naturalized somewhere in Australia.  Of these at least four become significant or major weeds.

Although often considered attractive many of these plants produce large quantities of berries or seeds. They subsequently spread uncontrolled into neighbouring land, often carried by birds or the wind, where they quickly establish at the expense of existing vegetation.

There are many ways to control invasive weeds, and total eradication usually requires a concerted effort over a long period of time. Methods of control include physical or mechanical removal, the use of herbicides and in some situations biological control agents. Once the weeds have been controlled it is essential to replace them with desirable species to provide competition.

What is a Priority Weed?

The South East Regional Strategic Weed Management Plan supports regional implementation of the NSW Biosecurity Act 2015. This plan identifies the state and regionally prioritised weeds for the south east region including the Illawarra. Under the Biosecurity Act 2015 there is no scheduled “list” of weeds although a range of weed species have been prioritised at the State and Regional level.

Listed on our website are the priority weeds for the Illawarra District Weeds Authority (IDWA) area of operation. The plants shown in the following tables are listed as State or Regional Priority Weeds throughout the local government areas of Kiama, Shellharbour City and Wollongong City. For more detailed information click on the name of the weed and you will be re-directed to the DPI NSW WeedWise site. 

Weed Control Management Plans

Weed Control Management Plans have been developed for some of the priority weeds listed in the South East Regional Strategic Weed Management Plan 2017 – 2022. These species specific weed management plans detail specific actions/control requirements that land managers must undertake to meet their General Biosecurity Duty obligations. It is important that land managers are aware of their duty and actions that they must take to discharge their duty in relation to these priority species.