Weeds are plants that grow where they are not wanted. Nevertheless, what is a weed to one person, may be a valued plant to someone else.

Seventy-seven plants have been officially declared as weeds under the Weed Management Act 1999 because these plants can cause, or have already caused, an adverse impact on our natural or agricultural environment. Once plants are declared weeds under the Act, there are restrictions relating to their trade, sale, import, movement and disposal.

Under Section 15 of the Act, a Weed Management Plan must be drawn up for each plant within 12 months of it being declared a weed. These Plans are drawn up by the Department of Primary Industries, Water and Environment (DPIWE), and go through a public consultation phase before becoming statutory plans under the Act.

Draft Weed Management Plans have been drawn up for all declared weeds and these set out restrictions and approaches for reducing or eradicating them. They apply equally to public and private landholders.

If there are declared weeds on my land, what does it mean?

• sale
• trade
• importation
• movement of declared weeds, or things that may be contaminated by declared weeds

It also includes requirements in relation to such things as boundary protection. Basically, the Weed Management Act puts obligations on all landholders, both public and private, to take an active part in either controlling or eradicating the weeds on their property, as per the relevant Weed Management Plan. In areas where declared weeds have not yet been recorded, it is everyone's responsibility to prevent the weeds getting established and to look out for new infestations.

If you travel from areas interstate or overseas infected with declared weeds, it is important that you check all your belongings for seeds, fruit and plant matter, or get quarantine officials to check them when you arrive in Tasmania. The importation of some plants is also restricted under the Plant Quarantine Act 1997.

How do I control weeds?

There are a number of key steps to successfully control weeds:

• Plan weed control activities carefully.
• Find out the different options for weed removal before starting.
• Make weed control activities strategic - start in areas that have few weeds and gradually work in towards the main infestations.
• Concentrate on clearing weeds from areas that are mostly in good condition.
• Be prepared to sustain the effort. You could actually make the problem worse by clearing too much too soon and not doing enough follow-up work.
• Get adjacent land managers to work together to eradicate the weeds.

Is there any funding assistance available to help control weeds on my land?

Some weeds have been declared Weeds of National Significance and there is funding available, through the Federal Government, to remove them.

How do I remove the Weeds?

The actions you need to take to remove weeds in your area depend on:

• the weed(s) you are dealing with
• the environmental conditions.

Successful weed control requires consideration of the characteristics of the plant itself, as well as the context in which it is growing. What may be a successful and acceptable solution in one situation may be ineffective or inappropriate in another. Seek professional advice before undertaking weed control work.

Often an integrated approach that uses a combination of control methods may be required to effectively deal with a weed.

These methods may include:

• pulling or digging out by hand or by machine
• mulching or establishing competitive vegetation
• grazing, mowing or slashing
• spraying with appropriate herbicides.

If using chemicals:
• take adequate safety precautions,
• always read the instructions on the label
• be especially careful near lakes and waterways as some chemicals harm aquatic ecosystems.

Some weeds need a variety of methods to successfully remove them and some follow-up work will nearly always be required. The importation of plants is controlled by the Quarantine Act 1908 (Cth) and the Wildlife Protection (Regulation of Exports and Imports) Act 1982 (Cth). All plants entering Australia will be assessed for their weed potential before entry is permitted. Plants considered potential weeds of land, freshwater and marine environments are prevented from entering Australia. In addition, produce is checked for contamination by weeds when entering Australia from overseas or moving between States. Hygiene practices and crop certification schemes are used in some areas to reduce the risk of the spread of weeds.

The National Weeds Strategy was launched in 1997 by Commonwealth and State governments to address weed problems of national significance which:

• Threaten the profitability or sustainability of Australia’s principal primary industries;
• Threaten conservation areas or environmental resources of national significance;
• Require remedial action across several States and Territories; and
• Constitute major threats to Australia’s biodiversity.

Please note that at the time of writing (mid-2006) the National Weed Strategy is under review and will be renamed the “Australian Weed Strategy”.

Weeds of National Significance

In 1997 the National Weeds Strategy Committee developed an assessment procedure to identify weeds of national significance (WONS) and to prioritise weeds over a range of land uses at the national level.

The criteria assessed in determining Weeds of National Significance are:
• Invasiveness
• Impacts
• Potential for Spread
• Socioeconomic and Environmental Values