Weed-control at home
Council has avoided giving specific recommendations about the type of herbicide to be used for each weed, as new herbicides are constantly being developed.
Herbicides are meant to be used only on the plants for which their use is registered. For some environmental weeds, there may not yet be a herbicide registered for use. However, there may be an off-label permit which covers these species.
The publication below provides details of appropriate herbicides, application rates, and alternative control methods for many different weed species:
If you cannot find the weed you are looking for in this publication, please phone us on 4474 1000 to speak with Council’s Invasive Species staff or email a picture to Council.
Weed growth and spreading
Weeds thrive on disturbance. As well as taking action to remove weeds, you need to look at what has contributed to the infestation, and treat the causes as well as the symptom (the weeds).
If reliance is placed on simply spraying weeds whenever they appear, you are embarking on an expensive spiral of increasing disturbance and increasing infestation. Healthy, vigorous native vegetation or pasture is relatively weed-resistant.
Timing is crucial in weed control. Remove weeds before they produce seed. If you are too late, collect the seed and burn it, bury it deeply, or place it in plastic bags in the sun to rot. The rotting process requires moisture so make sure you include some moist, green material.
Plastic bags are easily broken, so DON'T take weeds carrying light wind-blown seed to landfill, whether in bags or not.
Removing a weed may simply result in it being replaced by another rapidly growing coloniser of empty space, most likely another weed. Look at the whole picture and decide what you want to achieve before starting a weed control program.
Take action against weeds
You can be proactive and take action against weeds now, by doing the following:
- Learn to recognise weeds and take early action to remove them from your property. Monitor areas where you have imported materials, or created disturbance, and be ready to control weeds as soon as they appear.
- Get unfamiliar plants identified by an expert if you suspect they may be weeds.
- Council staff will be able to identify plants for you. Phone us on 02 4474 1000.
- NSW Agriculture, National Parks and Wildlife Service or South Coast Rural Lands Protection Board staff may be able to help.
- If you are taking a plant to be identified immediately, put it in a plastic bag and blow into the bag to increase the humidity before sealing it tightly.
- If there will be a delay of more than one day before you can get the plant to someone for identification, store it in the refrigerator.
- If the delay is more than a couple of days, you may need to press the plant to dry it. Place the plant specimen between several layers of newspaper under a heavy book or similar object so that it dries flat. It is very difficult to identify a plant from a curled and shrivelled specimen.
- Join or form a Bushcare, Dunecare or Landcare group and become active in rehabilitating weedy areas. Phone us to find out about groups that already exist in Eurobodalla Shire. You can also visit our Landcare web page.
- Talk to your friends and neighbours about environmental weeds. Discuss any weeds or potentially weedy garden plants they may have on their properties. Many people are willing to remove weeds once they are identified.
In the garden
Below is a list of things you can do to help prevent weeds growing in your garden:
- Don't dump garden waste - burn it, compost it, or take it to the tip in stout plastic bags. However, remember that plastic bags are easily broken. Do not take plant material carrying light wind-dispersed seed to the tip, unless it has been in a plastic bag long enough to have rotted first.
- Don't dump unwanted water plants into water bodies or into the drains. Don't buy aquarium plants with weed potential.
- Remove any weeds from your garden and replace them with plants that will not spread.
- Avoid planting any species whose seeds are packaged in edible berries which are not native to your local area, regardless of where you live, as birds can spread them over long distances. If you live close to the bush or other native vegetation, also avoid the weedier bulbs, and anything with fine wind-blown seed.
- Talk to your nursery about the weed potential of plants before you buy them.
- Do not extend your garden into adjacent vacant land.
- Eliminate nutrient-laden runoff from your garden.
- Don't use fertilisers unnecessarily.
- Collect animal faeces and compost them.
On the farm or rural block
Below is a list of things you can do to help prevent weeds growing on your farm or rural block:
- Avoid unnecessary soil disturbance.
- Avoid overgrazing as this creates ideal conditions for weed invasion.
- Monitor areas which have had machinery from outside the property, over them, for new weed arrivals.
- Clean off mowing and slashing equipment before moving between areas.
- Avoid driving over your property as much as possible, as it compacts the soil and may deposit weed seed.
- If you feed stock on imported food, do so in a restricted area so that it can be monitored for weeds.
- Quarantine new livestock for several days so weed seeds can pass through them in a confined area that can be treated later.
- Don't shift stock straight from weedy areas into areas of remnant native vegetation - give them a week in a 'clean' paddock first.
- Get to know the timing of flowering and seed production of the weeds on your block; time your slashing, mowing or grazing to reduce seed set, and the distribution of seed once it has been produced.
- Be vigilant and act early - don't wait until a few plants turn into a major infestation.
Weed control methods
There are various weed control methods you can use to help eradicate and control weeds on your property:
This is the cheapest method of weed control for small infestations, but it is time consuming. Young plants are often easy to pull out if soil is moist. If soil is dry or plants are big, you are likely to leave enough material still in the ground for the plant to grow again. Some plants will recover unless every bit of the root system is removed, and these are better sprayed.
Digging is better avoided if it will cause a lot of soil disturbance in an otherwise relatively undisturbed site, as this will only encourage the germination of more weed seed in the soil. A sharp knife is a useful tool in hand weeding, as it can be used to cut the roots below the crown on smaller weeds such as grasses and herbaceous plants. Try to minimise the amount of soil disturbance when removing weeds this way.
Slashing or mowing can be used to delay the production of seed if more permanent control can't be undertaken until later. However, it is not a permanent method of control itself, and if plants have already seeded, it can result in spreading that seed even further.
If repeated frequently enough, it can exhaust the underground food reserves of some plants, and eventually get rid of them. Bracken is an example of this.
Goats and other grazing animals can be used similarly to prevent seeding. Any stock applied at the right time and in adequate numbers can minimise seeding of annual grasses.
Goats are particularly useful on some woody weeds, notably Blackberry and Briar Rose. However, they need to be stocked in fair numbers to have much effect; they need good fencing and can be hard on any bush in the paddock.
Sheep may be useful in controlling fireweed, but they need to be present in large numbers at the crucial times of year.
Solarisation involves heating weeds to lethal temperatures under clear (or coloured) plastic. It can be useful for low-growing and semi-aquatic weeds, but will work best when they are growing in full sun. It may or may not kill any seed stored in the soil.
This method is best used for small infestations.
Plastic may need to be left in place for months, and should be well weighted down.
Fire can play a part in controlling weeds, though it can also pave the way for weed infestation by creating bare ground. Timing is important.
Burning in autumn could encourage weeds by leaving the ground bare all winter. Burning in spring is less likely to have this effect.
The burning of native grasses which are not being grazed, has been shown to be necessary for their health. Without regular burning, grasses such as Kangaroo Grass (which forms much of the native pasture in the region) can lose vigour, and become much more susceptible to weed invasion.
Lack of burning in the bush around towns may allow exotic plants which would not survive fire, to become dominant. Fire can also be used to stimulate mass germination of hard-seeded species such as Broom, which can then be sprayed.
Herbicides are very useful in the battle against weeds, but need to be used carefully. The use of non-selective herbicides (which kill every plant they contact) creates bare ground, which only encourages further weed invasion. It is always best, if there is the option, to spray with the appropriate selective herbicide to minimise damage to non-target plants.
Remember, herbicides are poisons, and precautions should be taken to avoid getting them on your skin or breathing-in the vapour. Wear overalls, rubber gloves and a face mask when working with herbicides. If spraying, stay upwind of the target plants, and do not spray in windy conditions. Always read the instructions on the label before use. Be aware that there are restrictions on using herbicides near waterways.
Herbicides are meant to be used only on the plants for which their use is registered. Check the label. For many non-agricultural weeds not listed on product labels, there may be an off-label permit which covers them. If in doubt, contact Agriculture NSW, the National Registration Authority, Council's Weeds Officers, or the product manufacturers.
Note that under the Pesticides Act 1999 it is an offence to use a herbicide in a manner that could cause injury to a person, damage to another's property or harm to a non-target plant.
When to use herbicides
- Only if no other effective and efficient method is available, and only after you have read the label.
- Apply herbicide when the plant is actively growing. This may be in winter for some species (such as the Bridal Creeper).
- Do not use herbicides when the plants are drought stressed, in extremely hot or cold conditions, or when plants are diseased.
- Don't spray when it is windy or if it looks like rain is approaching.
- For many plants, the best time to treat is between flowering and fruit set.
- Spray deciduous plants in late spring through to early autumn when in full leaf. If leaf colour has begun to turn, it is too late.
Methods of herbicide application
Spraying should not be done in windy conditions. If plants are tall, it may be easier and safer to slash them first and spray when there is vigorous regrowth. If old grass tussocks do not contain many actively growing leaves, they may also be better slashed first to promote new growth, which will take-up the chemical more readily. Avoid spraying non-target plants, especially when spraying vines whose foliage may be entangled with that of the supporting plant. To minimise damage to other plants, use a selective herbicide if possible. Mix it to the right concentration for the target species (found on the label) and spray to thoroughly wet foliage, but no more. If the plant you are treating has waxy leaves, you may need to add a penetrant to improve take-up of the herbicide. Adding dye makes it much easier to see where you have sprayed.
Weed wipers can be used to apply herbicides to foliage in a more controlled manner. There are a range of possibilities here, from wiping herbicide onto individual plants with a sponge in a gloved hand (useful for bulb foliage), to hand-held wick wipers, to larger wipers towed behind a tractor or quad bike. This method can be useful for removing taller weeds without affecting the pasture beneath them. Generally, wiping with two passes at 90º to each other is needed to ensure sufficient coverage. Check whether the chemical you plan to use is registered for this method of application.
Cut and paint
The cut and paint method is suitable for woody weeds. The plant is cut-off close to ground level with a horizontal cut, and an undiluted herbicide (usually glyphosate) is applied immediately to the cut surface. If you are too slow, air is sucked into the sap vessels, preventing take-up of the herbicide. In some plants, such as willows, it may be necessary to apply the herbicide to both the stump and the cut end of the rest of the tree. This ensures that the top part of the plant dies, rather than taking the root again if it is left lying on moist soil. For a larger stump, only the outer edge (just inside the bark) needs to be treated, not the whole surface. Wear rubber gloves and avoid moving around with an open container of herbicide. This method and the two below are best done as a two-person job.
Scrape and paint
The scrape and paint method is used for large vines and scrambling plants with a woody stem. Scrape 20cm to 100cm of the stem with a knife to expose the sapwood just below the bark. Within 20 seconds, apply undiluted herbicide to the scraped section. Don't scrape right around the stem - do only one-third of the diameter. Stems over 1cm in diameter can be scraped on two sides. If killing vines with herbicide, leave them to die in place - pulling them down can damage the plants they are growing over.
Stem injection is used on woody weeds which die in place when treated. There are purpose-built stem injection devices, but the job can also be done with a hammer and chisel or a cordless drill. You need to make an angled cut or hole down into the sapwood, just below the bark, and apply undiluted herbicide into the cut immediately. Don't drill too deeply, or you will get into the heartwood, which does not take up the herbicide.
Basal bark treatment
This treatment is used on young woody weeds and root suckers. Diluted herbicide (check label for rates) is painted or sprayed onto the bark at the base from ground level to 30cm high.
Identifying weed species after the bushfires
Rapid weed regrowth since the recent bushfires has had landholders asking questions about the type of weed species that have suddenly appeared, and where they start with weed control.
This short video will show you which species are weeds, which species might look like weeds but are not, and which ones you should spend your time controlling.