Priority weeds and Common weeds

Effective weed control is not only achieved by controlling the growth and reproduction of weeds within an existing population, but also by ensuring that weed seed reserves in the soil are depleted and by maintaining a strong, resilient pasture that minimises further weed germination.

Some weeds spread by reproductive means, while others spread by vegetative means. Others have evolved to reproduce by a combination of both, so it’s important to understand the target weed and ensure that individual plants are either controlled before seeding and/or all vegetative plant parts are removed, including the roots, stems, branches, stolons, tubers or other plant parts which may allow the plant to propagate vegetatively.

For effective weed control, an integrated management program needs to be implemented where a coordinated range of suitable chemical and non-chemical control methods are used. The following methods may be used depending on the suitability for control of the target weeds:

• Herbicide application.
• Grass Competition.
• Biological control.
• Slashing.
• Ploughing.
• Digging or Grubbing out (for small infestations).
• Use of farm animals such as sheep and goats for grazing management.

Some of these methods, however, may be more effective than others depending on the target weed. Used on the wrong weed, some of these methods may spread further.

It is important to ensure when implementing a weed management program that your chosen methods comply with your weed control obligations under the Biosecurity Act 2015. Ongoing control is required to control new germination’s and, in the case of some woody weeds, regrowth. This can be achieved by regularly checking your property for new growth, bearing in mind different weeds germinate and grow at different times of the year. Prior to control, care needs to be taken in correctly identifying weed species.

To achieve long term control, it is necessary to maintain a strong, competitive pasture to compete with new weed germination. If your existing pasture is badly deteriorated you should seek agronomic advice, as your best option may be to establish a new pasture.

If you are using herbicides, caution needs to be exercised. The product label and safety directions must be followed. The herbicide should be applied using correctly calibrated equipment under suitable environmental conditions to avoid damage to non-target plants.

The Local Land Services or your local agronomist can provide advice on correct selection, mixing and application of herbicides.

The NSW Department of Primary Industries also provide valuable advice on controlling weeds and pasture management on their website NSW WeedWise

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Azolla - Azolla pinnata and Azolla filicoides

Many dams have been noticeably covered with a reddish mat of plants recently following rainfall runoff filling dams loaded with nutrients, such as topsoil, stock manure and fertiliser.  

Azolla is a native, free-floating fern that is common in many still or slow-moving waterways. It is commonly used as an ornamental plant in garden ponds. There are two main types of Azolla that tend to be red in sunlight or green if shaded. Neither type is considered to be very problematic. 

Although Azolla creates a large, tangled mat that can quickly cover a dam’s surface and, from a distance, can appear to be algae, it is not harmful or toxic.   

Azolla is not harmful to stock that eat it or drink the water it is growing in. It is not harmful in domestic or garden water. In fact, many South-East Asian countries grow Azolla as stock feed for ducks and fish farms. Excessive growth on dams may cause mechanical problems such as blocked pump inlets, impeded water flow in drains or channels, or very dense growth may restrict stock access to watering points, particularly for young animals.

For more information and advice on identification and control, please visit the Local Land Services, Yass Valley Council Biosecurity Weeds Officer or your local agronomist.

Paterson's Curse - Echium Plantagineum

Paterson’s Curse is an erect low growing annual herbaceous plant. Paterson’s Curse germinates in autumn, forming rosettes. As the plant grows, the stems lengthen and branch, in early Spring small purple flowers develop.
Peterson’s Curse is poisonous to stock with prolonged grazing leading to liver damage. Paterson’s curse is particularly toxic to horses, potentially causing death in as little as a few weeks. In addition to being toxic to animals, Paterson’s curse has the ability to become rapidly established and smother germinating pasture as the rosettes spread and thicken.

For more information and advice on identification and control contact the Local Land Services, Yass Valley Council Biosecurity Weeds Officer or your local agronomist.

Capeweed - Arctotheca calendula

Capeweed is a low growing annual winter weed. It has deeply lobed green leaves and distinctive yellow daisy-like flowers. Capeweed is a prolific seeding plant and dominates paddocks throughout competing and smothering beneficial grasses and plants at the seedling stage.
Capeweed can be poisonous to stock if digested in high quantities. Chemical control is very effective on capeweed when applied pre-flowering.

For more information and advice on identification and control,  please visit the Local Land Services, Yass Valley Council Biosecurity Weeds Officer or your local agronomist.

Erodium - Erodium Cicutarium

Erodium, also known as Crows Foot or Common Stork Bill, is an annual herbaceous weed of pasture and crops. Seedlings develop a clustered rosette similar to that of Capeweed, before developing reddish stems and growing more upright. Erodium can out compete beneficial grasses and plants at the seedling stage due to the thick leaf cover of the rosette and the ability to grow up and over seedling grasses and smother them out. 

Although Erodium is palatable, in higher quantities it can be toxic causing photosensitivity in sheep. The spiked seeds can also injure stock, particularly when caught in the eyes and between the toes.

Hormone herbicides provide good control of young plants. Older plants are harder to control and relatively tolerant to glyphosate.

For more information and advice on identification and control, please contact the Local Land Services, Yass Valley Council Biosecurity Weeds Officer or your local agronomist.

Thistles 

Thistles are vigorous competitors. The dense, flattened rosette leaves smother desirable pasture species seedlings in spring reducing their early growth. Dense stands of mature thistles create barriers that hinder livestock movement. Thistles are prolific seeders and can spread quickly if not controlled. Although susceptible to herbicide control as rosettes, once established thistles are difficult and expensive to control. Dense thistle populations can reduce property values.

For more information and advice on identification and control, please contact the Local Land Services, Yass Valley Council Biosecurity Weeds Officer or your local agronomist.

African Lovegrass - Eragrostis curvula
African Lovegrass is a highly invasive grass species that is continuing to encroach on areas of the Yass Valley Council.

YVC Biosecurity Weeds Officers recently participated in a webinar hosted by NSW DPI and Local Land Services on managing African Lovegrass.

A recording of the webinar is below. Also below is a link to the NSW DPI Factsheet on African Lovegrass.

For identification and tips on the control and management of African Lovegrass, please contact YVC Biosecurity Weeds Officers on 02 – 6226 1477

Managing African Lovegrass Webinar

Managing African Lovegrass Factsheet