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PAMPAS GRASS
Pampas grass (Cortaderia selloana) is a t a l l
coarse grass with an attractive flower head. I t
is a native of South America. Two other r e l a t e d
species, pink pampas (Cortaderia jubata) a n d
toetoe (Cortaderia richardii) are found in New
Zealand and Tasmania
where they a r e
important weeds.
Pampas grass forms a large tussock one m e t r e
or more in diameter and over two metres h i g h .
It has attractive plumed seed heads carried o n
stems which can reach four metres in height.
Female plants have large fluffy plumes w h i c h
are preferred by gardeners to the smaller more
compact plumes of bisexual plants. The p l u m e
may vary in colour from white to pink o r
violet. Pampas grass flowers and sets seed i n
autumn, March and April being the p e a k
months.
serious weed of forests, parks and bushland i n
New Zealand and parts of Tasmania and New
South Wales.
flowering plumes are removed before t h e
pollen and seeds develop and are d i s p e r s e d
by the wind.
There is the possibility that pampas g r a s s
would be a big nuisance to asthma and h a y
fever sufferers as the plant produces a h u g e
volume of pollen. As the leaf edges are f i n e l y
serrated, they can easily cut the skin leaving
irritating welts and cuts.
2 . Provided the plumes are cut off well b e f o r e
seed maturity, there is no risk of s e e d
dispersal, so that plumes can be kept a s
decoration or disposed of in household
rubbish.
If cutting is done late in t h e
season, the stems should be handled v e r y
gently to prevent seed being shaken out. I f
there is a possibility of viable seed in t h e
plumes, place them in a large p l a s t i c
garbage bag, secure tightly and leave to r o t
before dumping at the tip.
Pampas grass is a long lived perennial. It i s
mainly spread by splitting the clump. However
there are two sexual forms of the p l a n t :
hermaphrodite
(bisexual) and female. The
female plant does not usually form v i a b l e
seeds on its own, but when fertilized by p o l l e n
from a bisexual plant, it produces 100,000 o r
more viable seeds from each flower h e a d .
Bisexual plants rarely produce seeds. Seeds
can spread by wind for distances of up t o
25km.
Until recently it was thought that only female
plants existed in W.A. However, b i s e x u a l
plants have since been found widely s p r e a d
throughout the SW of the state. As a r e s u l t
pampas grass has the potential to become a
serious weed in wetlands and disturbed a r e a s .
Pampas grass competes with native vegetation,
reduces conservation and aesthetic values,
reduces recreational access on tracks a n d
increases the fire hazard.
SUGGESTIONS
CONTROL
FOR
A DEVELOPING WEED
Pampas grass is frequently grown as a g a r d e n
ornamental plant but has sometimes e s c a p e d
from cultivation and invaded disturbed a r e a s
of urban bushland. In summer the dense t u f t s
of dead leaves become a fire hazard. It is a
THE
EASY
continued
OPTION
(Requires
vigilance)
1 . Early removal of plumes will prevent p o l l e n
formation. If there is no pollen to shed, n o
seeds will form.
It is vital that t h e
3 . Repeat each flowering season.
It can b e
expected that picking will become more
difficult each year as the size of the c l u m p
increases.
THE PERMANENT SOLUTION:REMOVAL & DESTRUCTION
1 . Grubbing
out
can
be b a c k - b r e a k i n g ,
especially with larger clumps, but i s
positively effective. Be sure to wear heavy
long-cuffed
gloves,
long
sleeves
and
trousers. Plants must be left upside down
with roots exposed to die. Because p a m p a s
grass can grow from old up-rooted p l a n t s ,
do not dump live pampas grass r o o t
material as this may help it to spread.
2 . Larger clumps may best be destroyed b y
using the chemical glyphosate, which i s
sold under various names.
Ask at y o u r
local garden centre or hardware store a b o u t
products
containing
glyphosate.
See
separate information sheet for chemical
dosage and treatment advice.
3 . The following
preparation
method
is
recommended in order to make t r e a t m e n t
easier and to avoid spray drift.
The Wildflower Society
throughout the state.
has
branches
Our Aim:( a ) Using a brush-cutter, reduce clump t o
a 1-1.5m high stump.
Avoid c u t t i n g
plants too short as this reduces t h e
leaf surface available for h e r b i c i d e
uptake.
( b ) Clear away debris so that cut leaves a r e
exposed and treat immediately.
( c ) Alternatively, cut clump can be l e f t
and treated later when regrowth h a s
reached about 20cm high.
( d ) Apply chemical by one of the methods
described in the separate i n f o r m a t i o n
sheet.
( e ) If spraying, keep nozzle low and do n o t
spray on a windy day. Avoid s p r a y i n g
adjoining, desirable plants.
( f ) Do not treat if rain is expected w i t h i n
2 - 3 hours.
(g) Remember, wear protective c l o t h i n g
and read and heed the m a n u f a c t u r e r ' s
warnings on the label.
4 . Follow-up treatment may be necessary a f t e r
original knock-down of plant.
Make s u r e
plant is dead before dumping at the tip.
To foster an appreciation and a w a r e n e s s
of the delicate
balance
of n a t u r e
through *
*
*
*
PAMPAS GRASS
ERADICATION
The study of wildflowers.
The cultivation of wildflowers i n
home gardens and public areas.
Conservation of wildflowers.
The support of legislation to p r o t e c t
wildflowers.
The Wildflower Society is a member o f
the Association of Societies for G r o w i n g
Australian Plants. (ASGAP).
The
Gordon
Reid
Foundation
for
Conservation is conducted as a L o t t e r i e s
Commission Initiative.
FOR
FURTHER
ADVICE
OR
ASSISTANCE re the control of p a m p a s
grass, contact the 'Pampas Busters' a t
Murdoch
Branch
of the W i l d f l o w e r
Society of W.A. (Inc.) on 9457-2896.
This project is dedicated to
Yve B-Wignall.
A Community Service funded by
the Gordon Reid Foundation for
Conservation
and conducted by the
Murdoch Branch of the
Wildflower Society of W.A. (Inc.)
March 1994)
THE
METHODS
OF
CHEMICAL
TREATMENT
FOR
CONTROLLING
PAMPAS GRASS ARE AS FOLLOWS:
DIRECT APPLICATION
Use the following to make up a c o n c e n t r a t e d
solution to paint or wipe on to the leaf surface.
Product*
Dilution
Zero
Neat chemical
Roundup 360 1L product to 2L water
Roundup CT
800ml product to 2L water
Paint or wipe herbicide solution on to e x p o s e d
leaf ends and along as many attached leaves a s
possible.
KNAPSACK
Add one of the following formulations of
glyphosate to 10 litres of water in a knapsack.
Product*
Zero
Roundup 360
Roundup CT
Active
Ingredient
Amount
in
10L Water
100
360
450
720 ml
200 ml
160 ml
g/litre
g/litre
g/litre
To assist wetting and penetration of h e r b i c i d e
into the plant, add the wetting agent "Pulse" a t
the rate of 20ml per 10 litres.
Spray the plant sufficiently to thoroughly wet
the live foliage, but avoid applying so m u c h
herbicide that it runs off the plant.
Do not use high pressures for spraying.
A
pressure of 200 kPa or 2 bar is suitable. T h i s
can be monitored by adding a pressure gauge
to the sprayer, or regulated by fitting a s p r a y
management valve (S.M.V.) which is set for t h a t
pressure (these are available from L a t h l a i n
Holdings, Jandakot).
SMALL
HAND-PUMPED
BOTTLE
SPRAYER
An alternative to wiping is to use a s m a l l
sprayer as used for window cleaning.
The
concentrations for this are:Product*
PAMPAS GRASS
ERADICATION
Dilution
Zero
100ml product to 200ml water
Roundup 360 100ml product to 500ml water
Roundup CT
80ml product to 500ml water
Apply 10 - 20ml to each plant, covering a s
much foliage as possible.
Use 20ml for b i g
plants over 2m in circumference.
----------
*Products named are examples only - o t h e r
products are available that have the same
strength of active ingredient.
Herbicide
information
supplied
by
the
Agriculture Protection Board.
For f u r t h e r
details on pampas grass control see the A.P.B.
Infonote No.7/92, available from the A.P.B.,
Baron-Hay Court, South Perth.
FOR
FURTHER
ADVICE
OR
ASSISTANCE re the control of p a m p a s
grass, contact the 'Pampas Busters' a t
Murdoch
Branch
of the W i l d f l o w e r
Society of W.A. (Inc.) on 9457-2896.
This project is dedicated to
Yve B-Wignall.
A Community Service funded by
the Gordon Reid Foundation for
Conservation
and conducted by the
Murdoch Branch of the
Wildflower Society of W.A. (Inc.)
March 1994)