Weeds mean different things to different people. However, they do share a common set of characteristics that include:
- Rapid growth;
- Production of large amounts of seed or other effective means of propagation;
- Ability to colonise quickly after disturbance;
- Ability to survive in a range of environments, often at expense of local species; and
- Impact adversely on the natural environment, economic productivity and health.
Weeds are plants growing out of their natural habitat or range from other countries or other parts of Australia (e.g. Qld Umbrella Tree is a weed in Northern New South Wales).
Noxious weeds - impact on agriculture or health and are required to be controlled by law
Environmental weeds - impact on native bushland resulting in loss of biodiversity but are not required to be cleared by law.
To view common weeds and fact sheets see 'Weed Profiles'.
Why are environmental weeds bad?
Invasion of native bushland by environmental weeds is recognised alongside land clearing, urban development and pest animals as one of the most significant causes of biodiversity decline in Australia. This is of particular concern in our region because we live in an area with extremely high biodiversity including the highest number of threatened species in the State.
Environmental weeds compete with native plants for nutrients, light and moisture and can stop native plants from regenerating. Weeds can alter fire regimes & fuel loads, change nutrient cycles, increase shade and change habitats. This can reduce habitat quality and lead to declines of native species. Weeds have an uncanny ability to dominate disturbed areas of native bushland at the expense of native species. Disturbances such as clearing, weed dumping and creation of unmanaged tracks can greatly increase the ability of weeds to invade bushland. You only have to look at areas subjected to sand mining to see how disturbance can favour a weed species. Control of environmental weeds is costly and time consuming. Stopping them before they get out of hand can save dollars and time.
Why do we have so many environmental weeds?
Our region supports amongst the highest diversity and density of environmental weeds in Australia. The high level of weed invasion is largely in response to our fertile soils and warm and moist climate, associated with the degree of land clearing and urban development (disturbances), and due to bushland remnants often being in close proximity to human habitations. Many of our serious environmental weeds have been deliberately introduced for horticultural purposes (e.g. Camphor Laurel, Lantana, Cat's Claw Creeper, Madeira Vine, Privet's, Ground Asparagus, Ochna/Mickey Mouse Plant) and have spread from where they were planted by various dispersal mechanisms.
How are weeds spread?
Weeds are able to invade bushland through dumping of garden waste; dispersal by wind or water, by birds and flying foxes spreading fruits and seeds and by attachment of seeds to animals, clothing or vehicles. Weeds dispersed by birds and flying foxes typically have black, blue, red or bright coloured or fragrant fruits, which are features that also assist the dispersal of many of our native plants. Some weeds grow vegetatively, which means they can strike by cuttings when dumped into bushland or spread by floodwaters. Weeds dispersed by wind often have small papery or fluffy seeds that can blow long distances from parent plants.
What can you do to help reduce the impact of weeds?
Here are six easy steps you can follow to help reduce the impact of environmental weeds on our native bushland.
Know which plants are weeds.
Identification posters and brochures are available at Council and on the North Coast Weeds Advisory Committee website.
You may be surprised to learn that garden plants such as Duranta, Murraya, Night Jasmine, Cocos Palm, Cherry Guava, Qld Umbrella Tree, Coral Berry, Ice-cream Bean and many others readily invade native bushland where they can cause significant environmental problems.
Glory Lily (Gloriosa superba) a garden escapee rampaging through the dune vegetation and nearby coastal gardens. This environmental weed is highly toxic and very hard to control because of its ability to grow from small fragments.
Do not plant species recognised as weeds.
Become a responsible gardener and plant local natives instead of species that are weeds. If you decide not to remove a plant that is a known environmental weed you should at least remove fruits and seeds to prevent the plants spread.
Do not dump weeds or their seeds in bushland or reserves or creek lines.
You should either compost weeds on site or place them in the bin or take them to the tip. Many plants that seem harmless in your garden can become invasive pests in bushland.
Don't plant exotic species that produce seeds or fruits that are attractive to birds and flying foxes.
Such species typically become weeds when fauna move them into bushland. Animals don't know which plants are weeds, they use colour and or smell to locate food items and weeds that share characteristics with natives are readily consumed and spread. By not planting these species you are not tempting our local fauna to feed on weed species.
Vine weeds, like the Madeira vine pictured smothering this tree are a serious threat to biodiversity.
Control weeds, and replace them with non-invasive species.
Removing weeds from gardens and bushland areas helps native species to dominate their natural habitat, and reduces the ability of weeds to spread. Less weeds means better bush. For details on control techniques see NSW Dept Primary Industries - Agriculture website or the Big Scrub Rainforest Landcare Group manual on Common Weeds of Northern NSW Rainforest.
Join a Landcare or Dunecare Group
Become actively involved in learning about and restoring our precious natural environment.
Community Support Officers (CSO's) can give you information about how to contact any groups working in your area.
If you live in the Brunswick Catchment which takes in the northern part of the Shire you can contact Georgia Beyer of Brunswick Valley Landcare on 02 6626 7128.
If you live in the Richmond Catchment which includes Wilsons Ck south to the Shire Boundary you can contact Johanna Kempf at Richmond Landcare Services on 02 6632 0012.
Wilson's Creek/Huonbrook Landcare Group Busting Weeds (Photo: S. Riley)
For Weedbuster Week 2006 residents were invited to the Council Administration foyer to check out samples of weeds found in the shire and seek advice on how best practice methods for weed control.