Non-Chemical Control

Non chemical control methods can be an effective part of an integrated weed management plan for serrated tussock. The methods listed should not be used as the sole method for serrated tussock control. The best outcomes, use in conjunction with other types of control methods.

Non-chemical control techniques comprise manual removal, mulching, and the use of fire. 

Chipping removes and kills plant with low soil disturbance, but can be labour intensive. - Source: Natasha Baldyga 

Manual removal (chipping)

Chipping, also referred to as hoeing, is the physical removal of the entire serrated tussock plant from the ground using a hoe or mattock. In the bare ground left by chipping, scatter pasture seed and fertiliser to increase ground cover and promote competition.

Once removed from the ground, shake soil from the roots or leave in a position with the roots exposed to dry out. Otherwise the plant may re-root and grow. If chipped while in flower, bag the whole plant, remove from the paddock and burn.

Ease of chipping will depend upon soil type. Serrated tussock is more easily removed from soft or sandy soils compared to heavy or clay soils. Manual removal can be used all year around, but preferably before serrated tussock flowers.

Manual removal of serrated tussock is suitable for:

• All land-use situations with scattered or light infestation levels.
• Follow up treatments to remove regrowth.

Advantages to manual removal

• Completely removes and kills plant.
• Low soil disturbance.
• Control without using chemicals.
• Can be carried out while doing daily property activities such as checking fences or water. Always carry a mattock (and seed for revegetation) on the bike or in the vehicle.

Disadvantages to manual removal

• Uprooted plants may survive if moist soil is left around their roots.
• Is labour intensive.

Mulching can be used to smother small serrated tussock infestations. - Source: Len Menzel 

Mulching

Mulching is the physical application of material, such as straw, wood chippings, plastic sheeting or carpet, over the ground to prevent weed growth. This method will stop all smothered vegetation from growing, including all beneficial vegetation. To be effective, re-vegetate desirable species into the mulch layer. Mulching can be undertaken all year around.

For best results using mulch:

• chip serrated tussock plants or spot spray with glyphosate.
• apply a mulch layer at least 10 cm thick to smother all existing vegetation.
• plant seedlings or tube stock of desirable species into the mulch or weed mat to provide competition with emerging weeds. Use a crow bar to create a hole for tube stock to be planted through the weed mat or mulch.
• regularly monitor for emerging serrated tussock plants, and other weeds.
• follow up any regrowth by spot spraying with glyphosate or manually remove.
• maintain the depth of mulch levels, as over time they will settle and decompose (Snell et al 2007).

Mulching is suitable for:

• Light or isolated infestations in urban areas. For example, parks, reserves, roadsides and backyards.
• Organic farming situations.
• Small area, high density infestations in environmental areas where vegetation rehabilitation is required. For example, creek banks or conservation native grasslands.
• Light infestations in difficult to manage terrain. For example, rocky, steep or treed country, or along fence lines.

Advantages to mulching

• Does not require chemical application.
• Does not disturb the soil.

Disadvantages to mulching

• Is not suitable for large scale infestations.
• Is non-selective.
• Can be expensive.
• Labour intensive.

Fire does not kill adult serrated tussock plants, therefore vigorous follow up control is essential. - Source: Charles Grech  

Fire

A hot serrated tussock fire will not kill adult plants, though it will remove biomass and destroy about 25 per cent of the serrated tussock seed bank. Mostly surface seed is destroyed as buried seed is unaffected by fire. Only use fire in combination with other control methods.

Burnt serrated tussock plants may regrow and fire stimulates the mass germination of serrated tussock seeds. Therefore, always carry out a vigorous follow up control program to remove serrated tussock seedlings, using an appropriate herbicide control technique suited to preserving the desirable background pasture species.

Do not use glyphosate following fire until enough green leaf material is available for chemical uptake. Avoid using fire for at least one to two years following the application of flupropanate as it removes the herbicide residual from the soil.

Serrated tussock will produce a hot fire year round, which may have harmful effects on desirable vegetation. Always use fire with caution and seek advice when required.

Fire is suitable for:

• Conservation native grasslands, where ecological biomass reductions are periodically required to maintain the health and rejuvenation of native species. Selective grazing by native and feral animals may increase serrated tussock populations in such situations, so burning may be one of few management options available.
• Degraded pasture situations where the removal of dry matter prior to ploughing is required.
• Urban areas such as large parks and reserves, only in collaboration with the local fire authority.

Fire is best used in late autumn to late winter—this may reduce seed-set and the summer fire hazard. If using fire, only burn once every two to three years.

Advantages to fire

• Rejuvenates native grasslands to maintain diversity and healthy growth.
• May reduce the serrated tussock seed bank.
• May postpone serrated tussock from seeding for the current season.

Disadvantages to fire

• Serrated tussock can regrow vigorously following fire and may produce more seed in the following flowering season.
• The seed bank of desirable native species may be too low to successfully compete with serrated tussock following a fire.
• Adult serrated tussock populations are a fire risk and should only be burnt with extreme care and caution—a hot burn conducted at the wrong time may generate a wind storm of seed heads, creating a dangerous fire risk.
• May leave large bare patches of ground.

Always contact the local fire authority, check current fire restrictions and if required, obtain permits.

Victoria
Country Fire Authority
03 9262 8444
www.cfa.vic.gov.au

More detailed information on non-chemical control can be found in the National Serrated Tussock Best Practice Manual.