Something is spreading fast along your back fence or through a garden bed, and before you decide what to do about it, you want to know whether it is one of the plants the law actually regulates. It is a fair question, because in New South Wales landholders carry a general biosecurity duty, which means dealing with certain weeds is not just good gardening but a legal responsibility. This article explains what that duty means in an ordinary suburban backyard, which weeds are treated as priority weeds across Greater Sydney, and how to deal with them in a way that does not make the problem worse.
Under the NSW Biosecurity Act, every landholder has a general biosecurity duty to prevent, eliminate or minimise biosecurity risks they know about, or ought reasonably to know about. Regional strategic weed management plans list the priority weeds for Greater Sydney, and the specific duty differs by species and by area. Your local council weeds officer is the authority to confirm exactly what applies to your property.
What a priority weed is in NSW
A priority weed is a plant that NSW has identified as a serious enough threat to the environment, agriculture or the community that landholders are expected to actively manage it. The term has largely replaced the older label “noxious weed”, and it reflects a shift in how the state handles invasive plants.
Rather than a single statewide list of banned plants, NSW works through a general biosecurity duty that applies to everyone who manages land. In plain terms, that duty means if you know, or reasonably should know, that a plant on your property poses a biosecurity risk, you are expected to take reasonable steps to deal with it. What counts as reasonable depends on the plant and where you are. To make that workable, the state is divided into regions, and each has a regional strategic weed management plan that lists the priority weeds for that area and sets out what is expected for each one. Greater Sydney has its own plan, so a weed that is a high priority in a rural region may be managed differently here, and vice versa. Some species carry specific legal requirements, such as a duty to notify or to eradicate, while others simply fall under the general duty to prevent spread. Because the lists are reviewed and updated over time, the single most reliable step is to confirm a plant’s current status with your local council weeds officer rather than relying on an old list.
Priority weeds commonly found in Sydney backyards
Most householders will never meet the rare, high-alert species. The ones that actually turn up in Sydney gardens are a smaller, familiar group, and learning to recognise them is the first real step. Here are the ones you are most likely to find.
| Weed | How to recognise it | Why it is a problem |
| Lantana | Sprawling shrub with rough leaves and clusters of small pink, orange or yellow flowers | Forms dense thickets that smother native plants and is toxic to stock and pets |
| Blackberry | Thorny, arching canes with toothed leaves and dark berries | Creates impenetrable thickets, spreads fast and is very hard to shift once established |
| Broad-leaf and small-leaf privet | Shrub or small tree with glossy leaves and clusters of small cream flowers, then black berries | Spreads readily by seed into bushland and is a well-known trigger for hay fever and asthma |
| Asparagus fern | Fine, feathery foliage with a dense, wiry root mat and red berries | Chokes out ground-level natives and forms a tuber mass that is tough to remove |
| Madeira vine | Climbing vine with fleshy, heart-shaped leaves and aerial tubers along the stems | Smothers trees and shrubs under its weight and regrows from tiny dropped tubers |
| Cat’s claw creeper | Climber with claw-like tendrils and bright yellow trumpet flowers | Blankets and pulls down established trees and is difficult to control once climbing |
| African olive | Small tree with dark green leaves, paler underneath, and small dark fruit | Forms dense canopies that shade out everything beneath and replaces native vegetation |
| Fireweed | Upright plant with narrow leaves and masses of small bright yellow daisy flowers | Spreads enormous numbers of wind-blown seeds and is toxic to livestock |
A plant turning up on this list is a good reason to act, but not a reason to panic. Several of these are common across Sydney, and the point is to recognise one for what it is and handle it properly rather than letting it run.
How to identify one with confidence
Getting the identification right matters, because misidentifying a plant wastes effort on the wrong target and can leave the real problem spreading. Before you treat anything, take the time to be sure of what you are looking at.
Work through the obvious features in order. The leaf is usually the best starting point: its shape, size, whether it is glossy or dull, and how it sits on the stem. Then the stem itself, which might be woody, thorny, climbing or fleshy, each of which narrows the field. Flowers, when present, are often the clincher, so note the colour, shape and how they cluster. Finally, the growth habit: whether the plant sprawls, climbs, forms a shrub or stands upright. The practical move is to photograph all of these clearly: a close-up of a leaf, a shot of the stem, the flowers and the whole plant in its setting, because a weeds officer can identify a plant from good photos far more reliably than from a description. When you are not certain, your local council weeds officer will confirm it, and that confirmation is worth getting before you spend a weekend removing the wrong thing.
Removing them without spreading them
With several of these weeds, how you remove them matters as much as whether you remove them, because a careless job spreads the plant instead of stopping it. The golden rule is to avoid leaving behind anything the plant can regrow from.
- Remove the roots, do not just cut the top. Many of these weeds, privet and blackberry among them, resprout from roots or crowns left in the ground, so cutting at surface level just delays the problem.
- Treat fragment-spreaders with extra care. Madeira vine regrows from tiny aerial tubers and asparagus fern from its root mass, so dropped pieces start new plants, which means gathering every fragment.
- Bag it, do not compost it. Declared weed material should go into sealed bags rather than a home compost or a loose pile, where seeds and tubers survive and spread.
- Handle safely. Lantana is toxic and blackberry is thorny, so gloves, covered arms and care are sensible with most of this group.
One more point worth knowing: disposal of declared weed material is not the same as ordinary green waste. Because seeds and tubers can survive and spread, this material often cannot simply go in the green bin, and your council can tell you the correct disposal route. Getting the removal and the disposal right is the difference between solving the problem and seeding it somewhere new.
What this means for your obligations
In practical terms, your general biosecurity duty comes down to a few reasonable things rather than anything dramatic. You are expected to act on what you know about, take sensible steps to keep it from spreading, and not let a problem on your land become a problem on someone else’s.
That means dealing with a priority weed once you have identified it, rather than ignoring it, and doing so in a way that stops it spreading to a neighbour’s yard or nearby bushland, which is where the real environmental damage happens. It is also worth keeping a simple record of what you found and what you did about it, because that shows you have taken your duty seriously if it ever matters. For a small patch you have correctly identified, this is often a job you can handle yourself with care. For a heavy infestation, a fragment-spreading climber, or anything you are unsure about, professional weed removal across Sydney takes it on in a way that deals with the roots and the disposal properly, so it does not quietly come back or spread while you are tackling it. Either way, the duty is about reasonable action, not perfection.
Stopping them coming back
Removing a priority weed once is rarely the end of it, because the seed bank in the soil and any missed fragments will try again. The follow-up is what actually wins the battle, and it runs across the whole growing season.
The key is timing. Check the cleared area regularly through spring and summer when growth is strongest, and deal with new seedlings while they are small and easy, rather than waiting for them to establish. Denying bare ground to weeds is the other half of it. A healthy cover of desirable plants or a good depth of mulch, generally several centimetres, shades the soil and makes it far harder for weed seeds to get going. Keep an eye on the spots where the weed came from first, since that is where it is most likely to return. A cleared bed that is mulched, planted and checked through the season stays clear, while one that is cleared and then forgotten is usually back to square one within a year.
Common questions about priority weeds in Sydney
Am I legally required to remove weeds on my property in NSW?
You have a general biosecurity duty to manage biosecurity risks you know about or reasonably should, which includes priority weeds. The exact requirement depends on the species and your region, so confirm what applies to your property with your local council weeds officer.
What is the general biosecurity duty?
It is the obligation under the NSW Biosecurity Act for anyone dealing with land to prevent, eliminate or minimise biosecurity risks as far as is reasonably practicable. For weeds, it means taking reasonable steps to manage priority species and stop them spreading.
Is privet a declared weed in Sydney?
Privet is widely treated as a priority weed across Greater Sydney, both the broad-leaf and small-leaf forms, because it spreads into bushland and affects health. Confirm its current status and the required action for your area with your local council weeds officer.
Can I put declared weeds in my green bin?
Often not, because seeds and tubers can survive and spread through the green waste system. Declared weed material frequently needs separate disposal, so check the correct method with your council rather than assuming the green bin is suitable.
Who do I contact about a weed I cannot identify?
Your local council weeds officer is the right contact. They can identify a plant from clear photos, confirm its legal status in your area, and tell you what action, if any, is required of you as a landholder.
What happens if a weed spreads to a neighbouring property?
Allowing a priority weed to spread can breach your general biosecurity duty, and councils can take action in serious cases. The practical priority is to control it before it reaches a neighbour or bushland, which is exactly what the duty is designed to prevent.
Dealing with it the right way
The sensible order is simple: identify the plant first, confirm its status with your council weeds officer, remove it in a way that does not spread seeds or fragments, then follow up through the growing season so it does not return. Treated that way, a priority weed is a manageable job rather than a looming legal worry. If you have something spreading and you would like it identified and dealt with properly, A1 Gardening and Landscaping Sydney offers a free on-site assessment, so you know what you are dealing with and how to put it right.
