Landowners are responsible for taking all reasonable and practical steps to minimise the risks associated with invasive plants under their control. This is known as the general biosecurity obligation (GBO). Your local government and Biosecurity Queensland provide invasive plant control support services but may also enforce landowner responsibilities if necessary.

Prohibited invasive plants

Prohibited invasive plants:

• are not present in Queensland
• would seriously threaten Queensland's agriculture industries, natural environment, livestock, human health and people's livelihoods
• if found in Queensland must be reported to Biosecurity Queensland within 24 hours of the sighting.

A person reporting the prohibited plants must take all reasonable and practical steps to minimise the risk of it spreading until they receive advice from an authorised officer.

Report suspect plant sightings

To report suspect sightings of prohibited invasive plants, contact Biosecurity Queensland on 13 25 23.

Restricted invasive plants

Restricted invasive plants:

• are established in Queensland
• seriously threaten Queensland's agriculture, natural environment, livestock, human health and people's livelihoods.

Under the Biosecurity Act 2014, there are 7 categories of restricted matter (i.e. restricted matter may include matter such as plants, animal diseases, invasive fish, insects, invasive animals and weeds).

Restricted invasive plants may fall into 1, a combination or all of Categories 2 to 5 (listed below). Under each Category the restricted invasive plant has listed restrictions. The specific restriction requirements also apply to a person when dealing with restricted invasive plants unless they have a restricted matter permit.

Restricted invasive plant categories and restrictions:

• Category 2: the invasive plant must be reported within 24 hours Biosecurity Queensland on 13 25 23.
• Category 3: the invasive plant must not be distributed either by sale or gift, or released into the environment.
• Category 4: the invasive plant must not be moved.
• Category 5: the invasive plant must not be kept.

Invasive plants

Invasive plants are not prohibited or restricted invasive plants.

Everyone is obligated to take all reasonable and practical steps to minimise the risks associated with invasive plants under their control.

Also consider...

• Find out more about the national tropical weeds eradication program.
• Read the Biosecurity Act 2014.
• Learn about preventing the spread of weeds after a natural disaster.

Taking a proactive approach to control weeds (called invasive plants in the Biosecurity Act 2014) is generally much better than waiting for problems to occur. Deciding on a weed management strategy early allows you to plan your activities and allocate a budget for dealing with your weed problems.

Doing nothing may save you money in the short term, but your property may suffer from weed impacts, which may cost you in the long term. You may also face penalties for non-compliance with invasive plant control laws.

Choosing a weed management strategy

To make cost-effective business decisions on weed control, you need to gather information on:

• the size of the problem on your property and how much it is costing you
• total costs of available control methods and likely benefits of each, including time frames.

Based on this information, you can perform a simple cost-benefit analysis on various pest management strategies for your problem. This may help you decide which of the broad strategies described below is best for your business.

Planned, ongoing management

Planned, ongoing weed management strategies have high initial and ongoing costs. Yet, this approach is also likely to deliver long-term benefits with reduced weed incursions and impacts.

Local eradication

If you have a small property with a well-defined problem, you may consider local eradication strategies. This approach has high initial costs but limited ongoing costs as only monitoring will be required. If successful, local eradication can deliver long-term benefits for your property.

Crisis management

If weed incursions are high and their impacts are obvious, you may decide to implement crisis management strategies. This approach has high initial costs but no ongoing costs. You will probably see reduced invasive plant impacts in the short term, but long-term benefits are unlikely.

Although landowners are not required to develop a property pest management plan for weeds (called invasive plants in the Biosecurity Act 2014), effective planning is an extremely useful management tool.

Benefits of planning

Developing a pest management plan for weeds will help you:

• effectively control these weeds on your property
• comply with invasive plant control laws
• integrate control activities and other components of your property plan
• coordinate control activities with your neighbours
• improve efficiency by ensuring control activities are prioritised and resources are used at optimal times
• monitor how well control activities are working
• report progress to funding bodies and local governments.

Developing and implementing a property pest management plan

Plan

Generally, a property pest management plan involves both maps and written information.

Your plan should:

• give background information on property and ownership details
• include a property map to help in analysing weed risks for your property
• define the weed plant problems on your property
• assess risks and identify priorities for weed control
• set overall goals and specific targets and describe the actions that you plan to undertake to achieve them
• describe how you plan to monitor your progress and measure your success.

You should also seek input from neighbours and weed control experts on your draft plan.

Act

Implement the control activities outlined in your plan within the set time frame and budget.

Check

You need to monitor your control activities and their effect on weed infestations on your property.

Review

The information gathered from monitoring will enable you to evaluate how successful you have been in implementing control activities and meeting your targets. You can then review your plan and make necessary changes to future weed control activities.

Also consider...

• Learn more about pest management planning.

Weeds (called invasive plants in the Biosecurity Act 2014) are able to spread rapidly and have unwanted economic, environmental or social impacts.

They can be very difficult to identify and may be confused with plants that are not invasive, including native or endangered species.

Some weed plants also look very different in their juvenile and mature stages.

It's important to correctly identify the weed to ensure that control methods are effective and appropriate.

Some factors to consider when identifying weeds are:

• where and when the plant grows
• its shape and size
• its leaf form
• its fruit and flowers.

Tools to help identify weeds

Our listings of restricted, prohibited and other invasive plants are a useful reference for weed identification.

There are many more online weed-identification tools to help you identify weeds.

Identifying weeds from specimens

If you cannot identify the plant using online tools or invasive plant identification publications, you can send a sample to the Queensland Herbarium for analysis.

Alternatively, you can submit a photo of the plant using Biosecurity Queensland's identify invasive plants form.

Reporting prohibited or restricted weeds

If you think you may have found a prohibited or restricted (category 2, 3, 4 or 5) invasive plant, immediately contact us online, by phone or in person.

Take photos and note the exact location of the plant so that it can be easily found.

Also consider...

• Subscribe to our e-newsletters and alerts for the latest information on weed (invasive plant) issues in Queensland.
• Get more information and support from the National Landcare Directory.

Herbicides control weeds (called invasive plants in the Biosecurity Act 2014) either by speeding up, stopping, or changing the plant's normal growth patterns. This affects the plants by drying out the leaves or stems, or by making it drop its leaves.

Types of herbicides

The use of herbicides is sometimes the only practical and selective method of managing certain weeds. Herbicidal applications are usually cost-effective control methods in bushland areas, particularly when funding is scarce.

In many cases, weeds are only susceptible to 1 specific herbicide, and it is important to use the correct product and application rate for control of that particular plant. Common mistakes include incorrect identification of the invasive plant or using inappropriate products chosen solely on price. In most cases, plants must be actively growing to be vulnerable to herbicide treatments.

There are 5 types of herbicides:

• broad spectrum - these work on a wide variety of weeds
• selective - these work on a narrow range of weeds
• contact - these destroy plant tissue at or near the point of contact (they do not spread around the plant), and require even coverage in their application
• systemic - these move through the plant's circulation system, and can be injected into the plant
• residual - these can be applied to the soil and destroy by root uptake. They remain active in the ground for a certain length of time, and can control germinating seedlings.

Safeguards for using herbicides

The Australian Pesticides and Veterinary Medicines Authority (APVMA) controls and regulates pesticides, including herbicides. APVMA assesses chemical products for toxicology, efficacy, environmental impact, residues, breakdown times and occupational health impacts. The APVMA scheme is recognised as one of the world's most rigorous safeguards.

Herbicide label information

It is extremely important to read and adhere to the information on the herbicide label.

This includes:

• signal heading (indicating the product's hazard level)
• trade name
• claims for use
• active constituent
• net contents
• directions and limitations
• withholding period
• storage instructions
• safety directions and first aid
• dangerous goods notification
• expiry date
• mode of action (type of herbicide)
• important notes.

By law, herbicides can only be used in accordance with the claims for use on the label. Most environmental plant applications are not listed on herbicide labels. In these cases, it is necessary to obtain an off-label permit.

Off-label permits for the use of herbicides

As the majority of environmental weeds are not listed under their species names for herbicide registration, an off-label permit has been approved by APVMA to assist Biosecurity Queensland, local government and environmental groups in managing these weeds.

Herbicides have been approved for use against a large variety of environmental plants. It is a requirement that all persons using products covered by this off-label permit comply with the details and conditions listed in the permit. Find out how to apply for a permit.

Also consider...

• Read the listings of restricted, prohibited and other invasive plants, which includes information on how to control various weeds.
• Use the APVMA permit search to get the most up-to-date herbicide registration information.

There are various application methods for treating invasive plants with herbicides. It's important to choose the right method for your particular problem and the types of herbicides you are using.

Foliar spray

In foliar spraying, the herbicide is diluted with water at a specific rate, and sprayed over the foliage to point of run-off (until every leaf is wetted, but not dripping).

This method is most suited to plants where compete coverage can be achieved. Advantages include quickness and economy. Disadvantages include the potential for spray drift and off-target damage.

Foliar spraying can be done a number of ways, including:

• blanket spraying using a boom spray from a vehicle
• a hose and handgun pump powered spray unit
• a low volume pressurised handheld or backpack spray unit
• with splatter guns (larger droplets at higher concentrations).

Basal barking

This method involves mixing an oil-soluble herbicide in diesel (or other recommended product) and spraying the full circumference of the trunk or stem of the plant.

Basal bark spraying is suitable for:

• thin-barked woody plants
• undesirable trees
• saplings, regrowth, and multi-stemmed shrubs and trees.

Basal barking will usually destroy invasive plants as long as the bark is not wet or too thick for the diesel to penetrate.

Stem injection

The stem injection method involves drilling or cutting through bark into the sapwood tissue of woody plants and trees to transport the herbicide throughout the plant.

It is essential to apply the herbicide immediately (within 15 seconds of drilling or cutting), as stem injection relies on the active uptake and growth of the invasive plant to move the herbicide through its tissue.

Drill and fill method

The drill and fill method is used for trees and woody plants with stems or trunks greater than 5cm in circumference, and is also referred to as tree injection.

This method uses a battery-powered drill to drill downward-angled holes into the sapwood approximately 5cm apart. Using a backpack reservoir and syringe can deliver measured doses of herbicide solution.

Only trees and shrubs that can be safely left to die and rot should be treated this way. If the tree or shrub is to be felled, allow it to die completely before felling.

Axe cut method

The axe cut method can be used for trees and woody plants with stems or trunks greater than 5cm in circumference. It involves cutting through the bark into the sapwood tissue in the trunk, and immediately placing herbicide into the cut. The aim is to reach the tissue layer just under the bark, which will transport the herbicide throughout the plant.

Using an axe or tomahawk, horizontal cuts are made into the sapwood around the circumference of the trunk at waist height. The axe is then leaned out to make a downward angled pocket to allow herbicide to pool. It's important not to entirely ringbark the trunk, as this will decrease the uptake of herbicide.

Cut stump

The cut stump method involves cutting off the invasive plant completely at its base (no higher than 15cm from the ground) using a chainsaw, axe, brush cutter or machete. A herbicide solution is then sprayed or painted onto the exposed surface of the cut stump, with the objective of destroying the stump and the root system.

It is essential that the herbicide solution is applied as soon as the trunk or stem is cut. A delay of more than 15 seconds for water-based herbicides and 1 minute for diesel-soluble herbicides will give poor results.

Cut and swab

This method is similar to the cut stump method, but is suited to vines and multi-stemmed shrubs. Here, the invasive plant stems are cut through completely, close to the ground. Herbicide is then applied immediately to the cut surface emerging from the ground, via spray or brush application.

Stem scraper

Stem scraping is used for invasive plants and vines with aerial tubers. A sharp knife is used to scrape a very thin layer of bark from a 10cm section of stem. Herbicide is then immediately applied to the exposed, underlying green tissue.

Wick applicators

This method consists of a wick or rope soaked in herbicide from a reservoir attached to a handle, or assisted with 12-volt pump equipment. The wetted wick is used to wipe or brush herbicide over the plant.

Also consider...

• Watch the video on herbicide control methods for invasive plants.
• Read the listings of restricted, prohibited and other invasive plants, which includes information on how to control various weeds.
• Use the Australian Pesticides and Veterinary Medicines Authority permit search to get the most up-to-date herbicide registration information.

Manual control

Manual control is the use of the hands or handheld tools to deal with weeds (called invasive plants in the Biosecurity Act 2014). An advantage of manual control is that it minimises soil disturbance, and decreases the likelihood of erosion and seed germination.

Hand pulling

Hand pulling aims to remove the entire plant, including its roots, from the soil. This method is useful for small-scale infestations. It is best to hand-pull weeds after rain, when soil is moist. Sturdy gloves should be worn to avoid prickles, blisters or sap burns to the skin. It is not appropriate for all weed species, such as those with underground bulbs.

Hand tools such as broad knives and trowels can be used to remove underground parts of weeds (such as bulbs) that may reshoot. In some cases it is necessary to dig out the crown of the plant. This requires the growing part of the plant to be cut beneath the ground using a knife.

Grubbing or chipping

This method requires weeds to be dug out using a mattock or chip hoe. Depending on the plant, it may be important to expose the root system, and remove the crown.

In some cases, the mattock or chip hoe is used to cut the stem of the plant below the ground. This method is useful when the ground is hard. Gloves should be worn to avoid blisters.

Mechanical control

Mechanical control is the use of powered tools and machinery to manage weeds and is best suited to larger infestations. Care should be taken to minimise soil disturbance.

Slashing, mowing, dozing, pushing and felling

At times, controlling weeds using mechanical methods is preferred. However, care should be taken when machinery is used in the process.

Disturbing the soil with mechanical control can:

• increase the likelihood of seed germination
• damage native vegetation.

In some cases it's possible to slash weeds using a tractor slasher or ride-on mower. Often this method is used where other favourable species will outgrow the slashed weeds. Some control contractors apply steam after the weeds have been slashed.

Bulldozers and chainsaws can be used on woody and tree weeds where they are pushed or felled and finally snigged (dragged away). These methods are only suitable in certain situations, as they create high levels of soil and vegetation disturbance. Also, shoots and seedlings require follow-up attention.

Grading or scalping the top layer of soil is an effective method of removing a seed bank. As this method greatly disturbs the soil, it is best suited for areas that are to undergo complete rehabilitation.

Also consider...

• Read the listings of restricted, prohibited and other invasive plants, which includes information on how to control various weeds.
• Learn how to prevent seed spread on your property.

Biological control involves the use of insects or pathogens (diseases) that affect the health of weeds (called invasive plants in the Biosecurity Act 2014). Usually, these biocontrol agents are from the same country of origin as the weed species.

Biosecurity Queensland undertakes biological control research in Queensland. Strict measures are in place to ensure that these agents do not negatively affect native plants and animals or horticultural and agricultural crops.

Biosecurity Queensland's biological control group is presently working on 10 weeds of concern to Queensland:

• bellyache bush
• cat's claw creeper
• lantana
• madeira vine
• mother-of-millions
• parthenium weed
• prickly acacia
• siam weed
• cabomba
• opuntioid cacti.

A number of biological controls have been released at strategic infestation sites, and are spreading to other infestations of their host plant.

Biological control agents can reduce the vigour, size and competitiveness of weed infestations; however, they rarely get rid of them altogether. Biological control works best in conjunction with other control methods.

Also consider...

• Read the listings of restricted, prohibited and other invasive plants, which includes information on how to control various weeds.
• Learn more about lantana biocontrol.
• Read Reclaiming lost provinces: a century of weed biological control in Queensland.

Environmental management aims to alter the conditions required by a particular weeds (called invasive plants in the Biosecurity Act 2014), and to destroy them without using herbicides.

Fire

Some weeds are fire-sensitive (fire will either destroy or suppress them). However, the susceptibility of plants to fire varies greatly. In some cases fire is used to destroy the weed, in other cases it is used to get access to the weed.

Be aware that some weeds actually benefit from fire. Using fire at times when seeds are developing or ripening can help to prevent the release of seeds, but here the timing of the burn is critical. This approach is most effective with annual weeds that depend on each season's seed crop.

The use of fire as a control method requires detailed planning, such as installing fire breaks, and organising personnel and equipment. In all cases, permits and approvals must be obtained.

Moisture and nutrient control

Some weeds require certain moisture and nutrient levels, and by altering these levels the plant becomes disadvantaged. Some infestations occur due to water run-off, where extra nutrients from gardens, paddocks or drains are carried in the water. If this nutrient supply is cut off, weeds are less likely to thrive.

Overlaying weeds with mulch, newspaper or black plastic (solarisation) are other ways of altering the growing environment for the plant, and will usually prevent plants from germinating. Commercial weed mats are also available.

Over-planting

Over-planting with native species is a long-term control strategy. The objective is to establish a canopy that will 'shade out' and out-compete weeds. This method is usually combined with other control measures.

Also consider...

• Learn how to prevent seed spread on your property.
• Read the listings of restricted, prohibited and other invasive plants, which includes information on how to control various weeds.