Perennial Weed
Grasses
Bush For Life
Fact Sheet
By Leanne Lawrence
Tussock Forming (Caespitose)
and Rhizomatous
D
isturbance to native habitats
due to vegetation clearance,
introduced animals, human
activities and the introduction
of many species of weeds, has
contributed to the successful
establishment of many weed
grass species within native plant
communities. Once small
populations establish on the
edge of native remnants, any
further disturbance such as fire,
movement of soil or vegetation
clearance creates a niche for
weed grasses to fill, leading to
displacement of native species.
Native understorey diversity
is an important component
in vegetation community
structure, sustaining much
of the microflora which in
turn contributes greatly
to ecosystem function,
leading to vegetation which
is better able to withstand
disturbance (eg. fire).
Impacts ...
Perennial weed grasses
• Have the potential to
invade all native habitats.
• Out compete native plants
for moisture and nutrients.
• Will displace native
species.
Inter tussock
spaces
Inter tussock spaces are
an important structural
feature of native
grasslands. It is in these
spaces that native lillies,
orchids and herbaceous
species find their niche.
Many perennial weed
grasses form dense mats
that close inter tussock
spaces, displacing
native species and
threatening native
ground cover diversity.
• Alter vegetation
community structure.
• Reduce inter tussock
spaces.
Ehrharta calycina (perennial veldt grass) infestation reducing the diversity of
native understorey species.
Life history...
Perennial weed grasses
• Reproduce by seed and in
some species, form underground
lateral rhizomes.
Rhizome
• Growth stages are determined
by their photosynthetic
pathway (energy intake) and are
categorised into summer (C4) or
winter (C3) growing species.
• It is during these active growth
stages that control treatments
are most effective.
Ehrharta calycina with shallow roots
and rhizome.
• Seed dispersal vectors include
birds, animals, invertebrates,
wind, water and humans.
Pentaschistis pallida with inflorescences. One of many grasses with prolific
seed production.
Perennial Weed Grasses
Management of Perennial weed grasses
• Minimum disturbance management strategies are effective in
controlling perennial weed grasses in native habitats (Table 1).
• Treating ‘outliers’ or isolated weeds in areas of higher native
diversity or ‘good bush’ and working towards the denser weed
infestation, over time will facilitate native plant regeneration.
• Knowledge of individual species’ life history is important when
implementing management strategies to ensure successful
control of specific weed grasses (Table 2).
Methods
• Minimum disturbance techniques are specialist
strategies implemented by bushcarers to reduce
off target damage to native plants and minimise
disturbance to surrounding soils.
Table 1
Method
Technique
Grass Type
Hand weed*
While hand weeding, soil is held on
either side of plant with one hand while a
screwdriver or weeding tool can be used to
help lever the grass out of the ground. Tamp
soil back down.
Small individuals with shallow roots/
rhizomes. Grasses in close proximity to
natives.
Cut & swab or wipe foliage#
Leaf is swabbed with a sponge applicator
bottle or weed brush containing herbicide.
Or tussock is cut between 2-10cm above
ground and wiped.
Smaller, leafy tussocks. Small populations.
Spot spray#
Using a spray unit with herbicide, tussocks
are individually sprayed ensuring spray does
not drift on to adjacent native plants. Where
appropriate, grass specific herbicides can
be effective.
Grasses with deep root systems (may
include lateral roots and rhizomes). Larger
populations.
Slash & spray#
Tussocks are cut with hedge shears or
brushcutter and after significant regrowth
occurs (usually about one month) herbicide
is applied with a spray unit.
Larger tussocks with deep roots/rhizomes.
Tussocks with significant thatch ie. previous
season’s dieback.
#All herbicide control methods should be carried out during the active leaf growth stage of individual grass species and before flower stem
emerges. This facilitates efficient uptake of herbicide.
* Hand pulling grasses is ideally done before flowering and seed set. If this is not possible, all flower and/or seed heads should be bagged and
removed from the site.
Identification
Bushcare principles
Many perennial weed grasses look similar
to native species; therefore correct
identification can be difficult particularly
before flowering. If positive identification
cannot be made, seek advice from your
Bush For Life Regional Coordinator if you
are a volunteer working on a Bush For Life
site, or alternatively, the relevant Natural
Resources Management Board in your
region.
• Always begin weed
control strategies
in areas of highest
native plant diversity
and work outwards
towards weed
infestations.
• Remove weeds with
minimum disturbance
to surrounding soils.
• Do not over clear;
this can open areas for
other weeds to invade,
limiting the opportunity
for native plants to
regenerate.
Herbicide Use
Secatuers
Supported by
Sponge applicator for
swabbing
Use of herbicide should always be
carried out following the manufacturer’s
instructions. Read the label and material
safety data sheet provided by the
manufacturer for the correct rates and use.
Perennial Weed Grasses
COMMON PERENNIAL TUSSOCK WEED GRASSES
SPECIES
Ammophila
arenaria Marram
grass
HABITAT
Beaches and sand
dunes
ACTIVE
Summer/Autumn
Seed, lateral and
vertical rhizomes
Spot spray
NOTE
Removing whole
plants may reduce
the stabilisation
of sand dunes.
Grassland/woodlands,
riparian zones
Ehrharta calycina
Perennial Veldt grass
Low nutrient,
open, disturbed soils
Winter/Spring
Will invade all
disturbed habitats, does
very well in shaded
well-drained soils
Winter/Spring
Will establish in
all native habitats.
Can dominate open
disturbed areas quickly.
Summer/Autumn
Seed
Slash and spot
spray regrowth.
Do not overclear
as E.curvula thrives
in disturbed soils.
Festuca arundiacea
Fescue
Disturbed soils, moist
areas, creeks and springs
Winter/Spring
Seed
Slash and spot
spray regrowth.
Prolific seeder
Phalaris aquatica
Phalaris
Grassland/woodlands,
riparian zones
Winter/Spring
Slash and spot
spray regrowth.
Larger plants
will retain previous
season’s growth,
increasing fuel loads.
Holcus lanatus
Yorkshire fog
Disturbed,
moist areas.
Winter/Spring
Seed
Spot spray, cut and
swab small plants
Can form a prolific,
persistent seed bank.
P Hyparrhenia
hirta
Coolatie grass/
Tambookie grass�.
Roadsides,
grasslands/woodlands
Summer/Autumn
Seed, tillers
Slash and spot spray
regrowth. Hand cut small
plants, removing tillers.
Potential to invade is
high due to tolerance of
a wide range of habitats
and prolific seeding.
Paspalum
dilatatum
Paspalum
Moist, fertile soils,
grasslands/woodlands,
riparian habitats
Winter/Spring
Seed, short
rhizomes
Hand weed/cut small
plants. Hand cut and
swab, Slash and spot
spray regrowth.
Plants can reflower
in a short period if seed
heads are removed.
Follow up is necessary.
P Pennisetum
macrourum
African feather grass
Sandy soils,
grasslands/woodlands
Summer/Autumn
Seed, lateral
rhizomes Hand weed/cut small
plants. Slash and spot
spray regrowth.
Mature plants can
develop extensive
fibrous roots and
rhizomes.
Pennisetum
setaceum
Fountain grass
Sandy soils,
grasslands/woodlands
Summer/Autumn
Seed
Hand weed/cut small
plants. Slash and spot
spray regrowth.
Seeds will persist
in soil for >6years.
Still used in gardens
as a landscape plant.
Pennisetum
villosum Feather grass
Sandy soils,
grasslands/woodlands
Summer/Autumn
Seed
Hand weed/cut small
plants. Slash and spot
spray regrowth.
Common on
roadsides and footpaths.
Grows to about 50cm.
Pentaschistis
pallida Pussy tail grass
Grassy woodlands,
disturbed soils
Winter/Spring
Seed
Hand weed isolated plants.
Cut and swab, spot spray.
Ensure positive
identification,
can be confused
with some native
Austrodanthonia spp
Piptatherum
miliaceum Rice millet
Disturbed soils,
roadsides, sandy soils
and creeklines
Winter/Spring
Seed
Slash and spot
spray regrowth
Flowers mainly
in spring but can
produce flowers
during all seasons.
Sorghum halepense
Johnson grass
Moist soils,
disturbed soils
Summer/Autumn
Seed, rhizomes
Spray during early
growth period (summer).
Follow up with spot spray.
Seeds will persist
for >5years in soil.
P Eragrostis
curvula African
love grass
Seed
CONTROL
Dactylis glomerata
Cocksfoot
Ehrharta erecta
Panic
Variable due to warm and
cool season cultivars
REPRODUCTION
Slash and spot spray. Hand
cut and swab smaller plants.
Important to
identify the relevant
growing period prior
to treatment.
Seed and short,
shallow rhizomes
Spot spray, hand weed. Cut
around root zone with knife.
Seeds will germinate
on bare disturbed soil.
Do not overclear.
Seed and short,
shallow rhizomes
Spot spray, hand weed.
Seed and
deep rhizomes
Soil stored seed
will germinate after
death of adults. New
plants can flower and
seed within 10 weeks
of germination.
Note: Nassella neesiana (Chilean needle grass) and Nassella leucotricha (Texas needle grass) have
not been included in this table. Both are Proclaimed plants and require specialist control strategies for
management. Contact the Adelaide and Mount Lofty Ranges Natural Resources Management Board for
further information.
P = Proclaimed weed
References and Further Reading
Gibbs, J. & Gibbs, R. 2001 Grass Identification Manual. Native Grasses Resources Group Inc. South Australia.
Jessop, J. Dashorst, G.R.M. James, F.M. 2006 Grasses of South Australia. Wakefield Press, South Australia.
Blood, K. 2001 Environmental Weeds a Field Guide for SE Australia. CH Jerram & Associates, Victoria.
Bradley, J. 2002 Bringing Back the Bush: the Bradley method of bush regeneration. Reed New Holland, Australia.
Brown, K. & Brooks, K. 2002 Bushland Weeds: A practical guide to their management. Environmental Weeds Action Network Inc.,
Australia.
Muyt, A. 2002 Bush Invaders of South-East Australia. R.G. & F.G. Richardson, Victoria.
Robertson, M. 2005 Stop Bushland Weeds. The Nature Conservation Society of South Australia Inc.
Weeds CRC www.weeds.crc.org.au/index_noflash.html