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Serrated Tussock
(Nassella trichotoma)
L A N D W A T E R L I F E
F A C T
S H E E T
Serrated Tussock is a weed of national
significance. It is a highly invasive species that can
seriously impact pasture and native grassland
communities.1,2,3
Serrated Tussock is native to South America.
Although it is thought to have been introduced to
Australia in the early 1900’s, it wasn’t officially
recorded until 1935 at Yass, NSW.4
It is estimated that Serrated Tussock infestations
now occupy 860,000 ha of NSW and costs over
$40 million per annum in lost agriculture revenue.
In NSW, its main infestations are in the Central
and Southern Tablelands and the Monaro plains.2
Why is it a weed?
Serrated Tussock is adapted to a wide range of climates and is not limited by soil type or fertility.
It will also grow readily in acidic soils. It will readily invade pastures, native grasslands and open
scrub, and will grow on all types of terrain and different aspects. It will quickly infest bare ground
and areas that have been disturbed, such as roadsides, overgrazed pastures or cultivated
situations. It will colonise steep, rocky and timbered areas.1,2,3
Serrated Tussock is also a weed that is mostly dispersed by wind and will easily spread between
paddocks and properties within a region. The species produces copious amounts of seeds
(individual plants are estimated to produce around 100 000 seeds annually). These seeds can be
carried up to 30 kilometres in the wind and remain viable in the soil after many decades. It can
also be spread by humans, animals and machinery.1,2,3
Serrated Tussock is also a drought tolerant species. The current drought conditions have resulted
in increased bare ground providing ideal habitat for Serrated Tussock regeneration.
Impacts on agriculture
Serrated Tussock is a serious threat to agriculture. It is described as potentially causing the
greatest reduction in carrying capacity than any other weed in Australia. It is estimated that heavy
infestations of Serrated Tussock can result in a 95% loss in production 3.
Serrated Tussock is unpalatable to livestock and will only be eaten if nothing else is available.
Serrated Tussock has a very low nutrient content and is insufficient to meet livestock
requirements. It has a high fibre content of 86%, crude protein levels as low as 4% and 3.3% crude
fat.3 If livestock are forced to graze pastures containing Serrated Tussock the energy used to
digest the fibrous leaves will be higher than energy acquired from digestion. This can cause
malnutrition and weight loss. If consumed in large quantities the fibrous leaves can form balls in
the rumen causing a loss of condition and eventual death.3
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2
Impacts on native vegetation
Native grasslands are one of Australia’s most threatened ecosystems,
with less than two per cent of their original distribution remaining. The
natural temperate grasslands of the NSW Southern Tablelands are
listed as an endangered ecological community under the Australian
Government Environment Protection and Biodiversity Conservation Act
1999.
The invasion of Serrated Tussock is a serious threat to the native plants
and animals in native grasslands. It competes with native plant species
for resources and significantly reduces native plant and animal species
diversity.
Serrated Tussock
negatively impacts pasture
production and native
remnant vegetation.
Photo: Greening Australia
Capital Region
Serrated Tussock is also very similar in appearance to many native
grasses and can go unnoticed for many years. Often, by the time an
infestation is recognised, many native grasses have been lost.1
Although Serrated Tussock is most problematic in native grasslands, it
can also invade other native vegetation communities, such as box gum
woodlands and dry sclerophyll forests.1,2
Description
Serrated Tussock
seedhead
showing slender flower
stalk and long awn on
each
floret
Plant:
An erect perennial tussock grass. Mature plants grow to 50cm
high with a base diameter of 25cm. Plants growing in less
fertile ground are usually smaller. They have drooping leaves
and seed heads. The seed heads change colour throughout the
year, appearing purple during flowering in late spring/summer,
golden brown during autumn, golden/bleached during winter
and green in spring.3
Leaves:
Bright green rolled leaves, 1mm wide. Feel rough when fingers
run down the leaf. An important identification feature is the
presence of a 1mm white ‘ligule’ (flap) at the junction of the
leaf and leaf sheath. This is visible when the leaf is pulled back
from the stem. When the leaf is rolled between the fingers,
the blades feel perfectly round with no flat spots or bumps.3
Flowering: Flowering stems to 95cm high.3
Seeds:
Tiny, almost round seeds enclosed in a purplish sheath. They
have a fine thread-like awn attached off centre at one end.
Seed heads droop to the ground on maturity.3
The white ligule at the junction of the leaf and leaf sheath is an
important identification feature of Serrated Tussock. Photo:
Jackie Miles and Max Campbell
SERRATED TUSSOCK
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b
a
d
c
Native grasses that are often confused
with Serrated Tussock:
a. Common Tussock Grass (Poa labillardieri)
b. Red anther Wallaby Grass (Joycea pallida)
c. Wallaby Grass (Austrodanthonia spp.)
d. Spear Grass (Austrostipa spp.)
e. Kangaroo Grass (Themeda australis)
e
Photos: Jackie Miles and Max Campbell
What can be done?
Legal responsibilities
Serrated Tussock is listed as a class 4 noxious weed under the Noxious Weeds Act 1993 in the Upper Lachlan
Shire. All land holders are responsible for controlling Serrated Tussock. The plant must be fully and
continuously suppressed and destroyed and can not be sold, propagated or knowingly distributed.
Prevention of spread
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Prevention is the most desirable control. This is best achieved by coordinated management with
neighbours and restricting contaminated machinery, stock and soil from entering your property.
All control programs should aim to reduce the amount of seed produced.
Desirable vegetation (including windbreaks) can be used as a barrier to effectively trap seed and reduce
wind dispersal.
Rabbit proof fencing can also help to catch tumbling Serrated Tussock seed heads.
Maintaining good groundcover (at least 80%) will assist to prevent establishment (Serrated Tussock is
opportunistic and will take advantage of bare ground resulting from overgrazing and drought).
Long term management relies on the establishment and maintenance of a competitive pasture that will
out compete tussock seedlings and resists reinfestation. One way to encourage the competition of native
grasses, which grow actively in summer, is to introduce a rotational grazing system where areas with
Serrated Tussock problems are not grazed as heavily over summer. The aim of this method is to reduce
seedling establishment, although it does not affect established adult tussocks.1,2,3
LANDWATERLIFE
FACT
SHEET
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4
Small infestations
Search paddocks annually for Serrated Tussock infestations.
Remove isolated or small patches of plants by spot spraying or chipping with a mattock.
Chipping should be done preferably before the Tussocks set seed. Desirable grass seeds could be distributed
over the bare patches created.
Do not chip out large patches of Serrated Tussock where a seedbank has built up because any soil
disturbance will cause germination of seeds.3
Large infestations
Large infestations on arable land can be successfully controlled with a program of cultivation, cropping and
pasture improvement. This will reduce the soil seed reserves as seeds buried below 20 mm tend not to
germinate. Seek advice on the suitability of these cultivating techniques for areas of land in a high risk
category for soil erosion.
Herbicides have also proven to be effective in controlling large infestations. Contact your council or state
weed management agency for information on the most effective herbicide that is registered for use to
control Serrated Tussock. It is important to note that some annual grasses and native grasses will be killed
by herbicides. Re-seeding will then be necessary.
Herbicide treatment alone usually results in reinfestation of Serrated Tussock from seed in the soil, so it is
important to incorporate other control methods in an integrated management strategy. Competition from
desirable pasture plants is especially important.3
Management and control in native grasslands
Serrated Tussock is a difficult weed to manage in native grasslands. To minimise damage to native vegetation,
early detection is essential and careful physical removal of isolated plants is recommended. Revegetation with
indigenous species is needed to prevent reinfestation. Larger infestations need to be contained using a
combination of available methods to minimise the spread of Serrated Tussock into native grasslands.3
Contacts
Upper Lachlan Shire Council Weed Manager 44 Spring Street (PO Box 10) Crookwell NSW 2583
ph (02) 4830 1000 fax (02) 4832 2066 website www.upperlachlan.local-e.nsw.gov.au
NSW Department of Primary Industries ph Weeds Hotline 1800 680 244 email [email protected]
website http://www.dpi.nsw.gov.au/agriculture/pests-weeds/weeds
References
1
Molonglo Catchment Group. Weed Fact Sheet Serrated Tussock (Nassella trichotoma), n.d. Available at: http://
www.molonglocatchment.com.au/
2
Osmond, R, Veebeek, M, McLaren, D.A. Michelmore, M., Wicks, B., Grech C.J. and Fullerton, P. Serrated
Tussock - National best practice manual. Victorian Government Department of Primary Industries, Melbourne,
2008. Available at: http://www.weeds.org.au/WoNS/SerratedTussock/
3
CRC for Weed Management. Systems Weeds of National Significance Weed Management Guide: Serrated Tussock
Nasella trichotoma, 2003. Available at: http://www.weeds.gov.au/publications/guidelines/wons/pubs/ntrichotoma.pdf
4
Southern Tablelands and South Coast Noxious Plants Committee (ST&SCNPC) Serrated Tussock Regional
Weed Management Plan 2003 – 2008, 2008. Available at: http://www.esc.nsw.gov.au/Weeds/
FSerratedTussockweedplan.pdf
This fact sheet was produced with the assistance of funds from the Lachlan Catchment Management Authority and was written by
Clare McInnes (Greening Australia Capital Region) on behalf of the Jerrawa Creek Landcare Group
August 2009
Jerrawa Creek Landcare Group
Bob Spiller (Secretary) PO Box 23 Gunning 2581 ph/fax: (02) 48458217 email: [email protected]