Kaleah Balcomb and Shahn Forrester of Gosford High School ...

Kaleah Balcomb and Shahn Forrester
of Gosford High School
Kaleah and Shahn up close and personal
with a Castor oil plant.

Our stretch of
weeds (approx. 100m),
with the school off to
the right.
Our school is located on the corner of
Showground Rd and Racecourse Rd in
Gosford on the Central Coast, NSW. Our
chosen area is situated along the side of the
school’s sports oval (diagram below). As
students we would like to take pride in the
appearance of our school, but unfortunately
the area has been neglected, which has
resulted in an unsightly weed problem. The
thin expanse of weeds looks completely out
of place, considering the rest of our school is
relatively tidy. In the rare occasion of rain,
the small ditch becomes a drain of sorts,
though as our weeds have grown this is
slowly being choked up.
One option, after the weeds have been eradicated, is to plant native water plants in the
drain, and install seats along the stretch of grass. This would prove a nice place to sit at breaks,
being in the shade for the majority of the day, and would also be useful for when sports matches
are being conducted on the grounds.
A multitude of weeds have been found along this section of our oval. Disturbingly, the
majority of these are noxious for humans and animals, and take over areas otherwise occupied by
native species. The main weeds of concern
are Broad-leaf privet (Ligustrum lucidum),
Narrow-leaf privet (Ligustrum sinense),
Green cestrum (Cestrum parqui) and
Lantana (Lantana camara), though we have
also found Wild tobacco bush (Solanum
mauritianum), Mulberry (Morus alba), Scotch
thistle (Onopordum acanthium), and
Castor oil plant (Ricinus communis) in areas.
If left alone, these species would continue to
expand, encroaching on our oval and
becoming much more inconvenient. By
replacing these weeds with natural
alternatives, the area would be much more
pleasing to view and would not have so
much of a cluttered feel.
Investigating up
close.
A weed is a plant that has the potential to degrade land and biological diversity, thus having a
detrimental effect on economic, conservation or social values. Or simply a plant out of place.

Gosford
High
School
Buildings
Our chosen area in relation to Gosford High School.
N
Weedy Area
School Oval
Profile of the area looking North
d
r
a
i
n

Ligustrum lucidum and Ligustrum sinense
There are forty to fifty different species of privets that are native to Europe and Asia, and two of
these, commonly known as narrow-leaf privet and broad-leaf privet, have become a major
concern in Australia. Abundant sightings of both these noxious weeds occurred in our area,
therefore counting them as plants not to be ignored.
Ligustrum lucidum
Common names: Broad-leaf privet, Tree privet, Glossy privet, Privet
(large leaf), Chinese white-wax tree
Family: Oleaceae
Origin: China and Japan
Ligustrum lucidum is still regularly seen in ornamental gardens
throughout southeast Queensland. A robust, vigorous, fast growing
plant, it likes to grow in moist, nutrient rich sites such as creeks and gullies. With a maximum height
of around 10m, the evergreen has closely packed branches, and as a young plant grows
aggressively resulting in the possible displacement of native understorey.
The oval leaves have pointed tips, are 12-13cm long and 5-6cm wide. They are a glossy
dark green colour, pale and dull underneath. Their texture is leathery, and the leaves have a
smooth margin and are placed in opposite pairs around the stem. Lenticels (small brown bumps)
can also be identified on the stem.
Heavily scented terminal panicles of white flowers occur in summer (mainly January to
March) are highly allergenic, and grow to
approximately 0.5cm long. They are
Large-leaf privet in
amongst other weeds.
clustered in a conical shape of 25cm long
on branch tips. The green berries mature
in winter to a purple-black colour, and
grow to just under a centimetre in length.
Broad-leaf privet is dispersed
both by birds and water. The seed is
spread deep into the bush by fruit-eating
birds, both native and exotic, and is
washed down waterways, producing
prodigious numbers of rapidly growing
seedlings. As a result, it infests waterways
and creeklines, and shades out and
replaces native species, which leads to an
ecosystem dominated by weeds. This
species of privet is also capable of
crowding out native trees, and can slow
down or stop the germination of native
seedlings.
In our area, Ligustrum lucidum has
helped to choke the drain, and has
unseated any native species. It is well
suited to the area, as it likes the kind of
environment that we have here.

Ligustrum sinense
Common names: Narrow-leaf privet, Chinese privet, Hedge privet
Family: Oleaceae
Origin: China
Note: many features of Ligustrum sinense are similar or the same as those of
Ligustrum lucidum. If features are not specified, it is assumed that they are
the same as is mentioned above.
Ligustrum sinense grows up to 5m high, and is a shrubby tree with dense multi-stemmed
trunks. It was formerly used extensively for hedging. It is a highly invasive, hardy plant, which has
narrow oval leaves with wavy margins. The deep green leaves grow in pairs, and grow to 6cm
long and 3cm wide. Short, fine hairs can be found on the veins and stalks of young leaves, and
similar to broad-leaf privet, lenticels can be
found on the stems.
The small white flowers have four
petals, and occur in dense sprays up to 10cm
long at the end of branches, from September to
December. The seeds germinate easily, and the
oval berries grow to 0.6cm long.
Narrow-leaf privet is also spread by
birds and water, though it seeks more fertile
soils, such as rainforest edges and watercourses
affected by urban runoff. It rapidly invades
Looking down
at Ligustrum sinense.
bush margins and waste areas, and threatens
native forests. It easily transforms natural
habitats to one overrun by weeds, as it has done
at our school.
Possible control methods
Physical: Privet seedlings are best dealt with by hand. This is the simplest and cheapest solution,
which consists of grabbing the base of the weed and pulling up all the roots. Plants that have no
seeds on them can be left on the ground or composted. Stopping plants from producing flowers
and fruit by pruning heavily is an interim strategy that can also be used.
Chemical: There are three main possible chemical control methods; the cut and paint technique,
tree injection or spraying. The cut and paint technique consists of cutting the stem of the plant
horizontally as close to the ground as possible, then applying an undiluted herbicide (such as
Glyphosphate) to the stump within 20-30 seconds. Tree injection or frilling or chipping is more
suited to Broad-leaf privet, and it involves using a drill, sharp chisel or axe to make holes or cuts
at an angle of 45 ° in the trunk at 5cm intervals, then filling these holes with herbicide. Spraying
would be the last considered option, using ‘Pulse’ or another penetrant in fine weather during
spring or autumn which is privet’s active growing season. However, spraying is inconvenient as it
would disable use of the school oval for a time afterwards.
Mechanical: Mowing is generally an option to control privet but the unique geography of our
area proves this to be an awkward solution.
Fire: Burning is a possibility, though is an unlikely method considering our site is situated on school
grounds.

Lantana Camara
In Australia Lantana is a Weed of National Significance (WONS). It is
considered one of the worst weeds as it is such an invasive species that
causes significant damage that affect both environmental and economical
factors in our country. Lantana needs to be controlled as it is a serious threat
to biodiversity in several World Heritage-listed areas, including the Blue
Mountains and Frasier Island. Currently the weed is only causing damage in
the New South Wales and Queensland areas; however it has the potential to
spread to Victoria, South Australia and south-western Western Australia.
Lantana Camara
Common names: Lantana, Shrub Verbena
Family: Verbeneceae
Origin: Mexico, Caribbean, Central and South America
Lantana is still popular as an ornamental plant although this is no longer advised. The thick
shrub’s growth habit changes with different individuals. Their form varies from shrubs, to climbers
or small clumps. Lantana grows in soils that are rich in organic matter but can also survive in areas
that have well drained clay or basalt soils. It prefers areas of high rainfall though will not survive
well if the temperature has a tendency to drop below five degrees Celsius.
Lantana infests the sunny areas along the sides of roads or in pastures, mainly where the
land has been disturbed. It is best to get control of Lantana before it becomes a big issue as this
plant can grow up to 4m tall. Another reason to get quick control is because it spreads quickly and
easily, through animal droppings. Insects are attracted to the flowers and pollinate them giving
them the power to produce up to 12 000 seeds a year. Lantana also maintains its area through
one of its “qualities”; Lantana is allelopathic and can release chemicals into the surrounding soil which
prevent germination and competition from some other plant species. (Weed management Guide –
Lantana – Lantana camara.)
The teardrop shaped leaves average in about 20-100mm in length, and are arranged in
an alternating format. They are bright green and covered in a fine hair and when crushed release
a strong smell. The stem is square in shape and is woody as well as prickly to touch.
Flowers are in compact heads that have approximately 20-40 individual flowers in each.
The colours vary (red, orange, yellow, white and pink) and several different colours can appear
on the head of one flower. They are clustered in a conical shape of 25cm long on branch tips. The
green berries mature into a purple-black colour and enclose only one seed.
Lantana is one of the more abundant weeds in our area, and if it were to be left any
longer it would grow to an even more significant size. It needs to be taken care of immediately to
ensure that it does not grow to an extent that it would be extremely difficult to remove.
Possible control methods
Physical: This is only appropriate for seedlings, as removing large plants manually would be a
back-breaking procedure. Gloves should be worn as protection from spikes.
Chemical: Herbicides could prove quite costly for the removal of our entire infestation. It also
removes any plants that we wish to remain there. However there is herbicide that has been
developed that is designed specifically for Lantana it is called Lantana DP 600. The herbicide must
be sprayed over the leaves as the herbicide then spreads throughout the plant. This chemical has
been tested and would be our choice of herbicide.
Mechanical: Slashing and bulldozing is used in some cases however, the soil disturbance makes regrowth
of lantana highly likely. It also provides an increased risk of erosion and makes the area

susceptible to other types of weeds. This would not be a viable option for us given the
geographical landscape.
Biological: There have been around 30 insects introduced over the last 90 years for the sole
purpose of controlling Lantana. There are four that have worked effectively they include two
beetles, a fly and a bug. These have already been introduced to their “potential range” and it
would prove a difficult exercise for us to get a hold of extra species.
Fire: This proves an effective method after first using a mechanical control. However, a permit is
necessary and it is uncertain if this would be an appropriate method for a school yard.
Cestrum parqui
In the Hunter region Green Cestrum is a Weed of Regional Significance
(Significance Plants that have or may have a significant impact on human and
animal health, or the natural Biodiversity of the region, definition from the
Hunter and central coast Weed Forum). It was introduced, like many weeds,
as a garden/ornamental plant. However it soon became out of control,
after birds spread the seeds easily to many agricultural areas. Green
Cestrum is a highly toxic species for stock. It is no longer common in areas
for voluntary reasons and because it is a weed of significance we must do our bit to control the
spread of this weed.
Common names: Green Cestrum, Chilean Cestrum, Green Poisonberry.
Family: Solanaceae
Origin: Native in Central and South America
Green Cestrum is a perennial shrub that can grow up to 3m tall. It is spread through bird
droppings and along rivers where the seeds are easily transported. It is an invasive species that is
possibly toxic to humans.
The leaves can grow to a length of 12cm and are arranged in an alternating format. They
are dark green as well as smooth, shiny and pungent when crushed. There are multiple stems each
arising from each basal crown.
Flowers are long (approximately 2.5cm in length) and tubular in shape. The colour
changes from green to yellow once mature. During the day the smell is quite unpleasant however
by night it releases a pleasant scent. The ovular berries are purplish-black and have a diameter
of 1cm. Inside they have seeds that are either black or brown and 3-4mm in length.
Green Cestrum
The flower
The fruit/berries
Possible control methods
An integrated control method is the preferred sort. There are many controls to choose from
however not all of them are appropriate for the type of infestation we have.

Physical: This is only appropriate for seedlings as large plants would be a back-breaking
procedure and generally not a practical method. This is the least effective method
Chemical: Herbicides although expensive are the most effective method. There are several types
of herbicides available for use.
Name of Chemical Rate Comments
Glyphosate 360 g/L Undiluted Apply the chemical with a
paint brush (Scrape Stem)
Amitrole + ammonium
thiocyanate
1.1 L in 100L Water Apply by spray before
flowering during Active
Growth.
Picloram +2,4 -D 650mL per 100L of Water Apply by spray at active
growth
Bottom right: Shahn identifying green cestrum (by smell).
Below: Shahn and Kaleah making sure it really is green cestrum.

il
Wild Tobacco, Castor Oil Plant, Scotch Thistle and Mulberry
There are only one or two specimens located in our area of each of these species. They
are not a major issue, however if left unaddressed they would soon spread out of control. These
are best just pulled out by hand and disposed of carefully.
Castor Oil
Scotch thistle
Scotch Thistle
Wild Tobacco
Mulberry

Management Strategy
An integrated control method is the preferred sort. There are many controls to choose from,
however not all of them are appropriate for the type of infestation in our area.
We would aim to proceed with our management plan in the summer, ideally just before
the summer holidays, so there is a greater extent of time that students are not at school. This would
also allow time for the pesticides to dissipate without children being exposed to them.
1. Pull out seedlings of all species by hand (using gloves), making sure roots are fully
removed. Bag to prevent spread and germination.
2. Remove the rubbish of the ground which is not aesthetically pleasing at all. We would
include them under the umbrella of ‘weeds’, apart from the fact that it is not a plant.
3. Use the cut and paint technique on weeds of a more substantial size (i.e. privet, wild
tobacco bush), using undiluted Glyphosphate. This contains, (as detailed before), the
cutting of the stem as close to the ground as possible, then painting with the herbicide. If
cutting at the base is impractical, cut higher to remove the bulk of the plant, then cut again
at the base and apply herbicide, using as little as possible and ensuring there is no runoff.
4. Spray Lantana Camara leaves with Lantana DP 600.
5. Cover the area with woodchip or another groundcover to prevent erosion.
6. Restrict access to the area for a certain amount of time to allow the chemicals to drain out
of the soil.
7. After making sure there is no regrowth of the weeds, plant native shrubs in the area. This
could be done as a school activity.
8. When plants are stable, install seats along the edge of the oval where there is maximum
shade.
9. Monitor the area and remove any weeds at the first sight of germination (using the most
relevant management) so that they do not become a problem.
Possible native species we could plant alongside the oval include Grevilleas (Grevillea hookerana,
Grevillea juniperina), Bottlebrush (Callustemon pinifolius), Tea tree (Leptospermum squarrosum), and
Kangaroo Paw (genus Anigozanthos). We could also plant several species of wattle, but this would
not be our first choice due to possible allergies and hayfever of the students. Closer to, or in the
small drain, we would plant native Australian water plants such as reeds, to stabilise the
ecosystem.
This method is not the most cost effective option, but we believe it to be the most suitable
and efficient method for the area, hopefully removing the weeds permanently. In relation to the
expense, we would enquire about an environmental grant from the Council or other sources.
Once this method has been completed, it should be relatively easy to maintain the area,
needing only a regular check to ensure that there is no regrowth. If any regrowth does occur, it
can be taken care of while it is still a small plant.
Overall, once the area has been cleaned up and the seats installed, it would be an
extremely pleasant place to sit and eat lunch or recess, due to that side of the oval being in shade
for the majority of the day (due to the eucalypts). When sporting events occur, players and
spectators don’t have to stand an uncomfortably close distance to an area dominated by noxious
weeds, but can relax close to eye-pleasing natives. To dispose of the weeds in this area would be
an advantage to all.

Sketches of the area
Draft sketch of a sample section Final sketch of the same section
note: this is a sample of our weedy section. The entire length of the section is, in general, the same,
with some variation.
Key
tree
Wild tobacco bush
(Solanum mauritianum)
Small-leaf Privet (Ligustrum
sinense)
Mulberry (Morus alba)
Lantana (Lantana
camara)
Broad-leaf Privet
(Ligustrum lucium)
Green Cestrum
(Cestrum parqui)
Boundary of weeds
(where the school oval
begins)
ditch/drain

Pictures from our area (Gosford High School)
Wild Tobacco bush (Solanum mauritianum)
Castor Oil (Ricinus communis)

Lantana
(Lantana camara)

Scotch Thistle (Onopordum acanthium)
White Mulberry (Morus alba)
More Thistle

Broad-leaf Privet (Ligustrum lucidum)
Narrow-leaf Privet (Ligustrum sinense)
Green Cestrum (Cestrum parqui)

Kaleah checking out the Scotch
Thistle (Onopordum acanthium)
General Photos of our area
Shahn looking at Lantana
camara (with the Solanum
mauritianum nearby)

Again, looking down from the
school oval at Lobelia, Lantana
camara and Cestrum parqui.
Looking down into the trough.
Ligustrum sinense in the
background, with Solanum
mauritianum to the left and
Lantana camara towards the
front.
A massive jumble of weeds!

More Lantana from our area.
Kaleah, Shahn and Cestrum parqui.

Get me out of this ditch!
Kaleah pacing (to approximate the
length)
What’s this?

Gosford High School . . .
. . . and our area . . .
. . . and us!

Getting friendly with the castor oil leaves.

Bibliography
Books and Publications
• Auld,B.A. and Medd R.W., Weeds; an illustrated botanical guide to the weeds of Australia,
Inkata Press, Melbourne, 1987
• Numerous pamphlets, calendars and other quick guides to weeds.
Media
• World Book Encyclopedia Disk, IBM Corporation, 1998
An example of the websites we used follows. There are variations of these to suit the different
weeds, and we also used various weed identification sites
• www.bfns.org.au/index.php?c=3&w=22
• www.gardenguides.com/flowers/annuals/lobelia.htm
• www.holistic-online.com/Herbal-Med/_Herbs/h260.htm
• www.manly.nsw.gov.au/Page.asp?z=5&c=151&p=487
• www.newcastle.nsw.gov.au/services/environment/greening/plants.cfm?inc=wild_tobacco
• www.northwestweeds.nsw.gov.au
• www.nrm.qld.gov.au/pests/weeds/declared_plants/broad_leaf_privet.html
• www.weedsbluemountains.org.au/lantana.asp
• www.weeds.crc.org.au/main/wom_lantana_c.html
Many thanks to our teacher Mr Jackson who helped us a lot in identifying the weeds.
Photos by Shahn Forrester.
Sketches by Kaleah Balcomb.