What is an environmental weed?
Unfortunately, some plant species that have been introduced to the Blue Mountains, either from other regions of Australia or from overseas, have developed into environmental weeds.
Why should we be concerned about environmental weeds?
Why do some introduced plant species become environmental weeds?
Locally indigenous vegetation communities that have been disturbed, for example by clearing or infrastructure development, are especially susceptible to weed infestation.
Urban gardens are a major source of environmental weeds in Australia (Gallagher, Leishman 2014).
Plant seed can be widely distributed by wind, water, humans and other animals, particularly birds. For example, the seed of Buddleia davidii (Butterfly Bush) is widely dispersed by wind, and this plant regularly infests Blue Mountains National Park and the GBMWHA. The seed of environmental weeds like Holly, Privet and Arum lily can be distributed long distances by birds. Plant fragments may be swept down streams during heavy periods of rain, and become established as viable plants in Blue Mountains National Park. Trad (Tradescantia fluminensis) is often spread in this way.
There are plant species, such as bamboo, that spread rapidly via underground stems (rhizomes).
Also, the broken branches of certain plant species, such as willows, can establish roots and become viable plants when soil is moist.
Environmental weeds can seriously disrupt the amenity of residents and communities, as happened when Prickly pear infested eastern Australia for many decades. In the Blue Mountains, environmental weeds such as Blackberry, Holly and Privet have been infesting public parks, scenic walks and lookouts, Blue Mountains National Park, and private gardens and property for many decades.
Weeds are expensive to control. Blue Mountains City Council (BMCC), the NSW National Parks and Wildlife Service (NPWS) and other government, non-government and industry entities annually expend considerable financial resources on the control of environmental weeds.
Environmental weeds destroy agricultural and other economic assets. The CSIRO estimates that weeds cost the Australian economy approximately five billion dollars per year.
What can you do to help control environmental weeds?
Additional environmental weed control tips for gardeners
Plant selection advice for gardeners
Common environmental weeds of the Blue Mountains
Check your property for these common weeds:
Agapanthus, Arum/Calla lily, Asparagus fern, Bamboo rhizomatous species, Blackberry, Blue periwinkle, Broom species, Butterfly-bush or Buddleia tree, Cassia, Cherry laurel, Cootamundra wattle, Cotoneaster species, Crofton weed, Day lily, English ivy, Evergreen Dogwood, Ginger lily, Gorse, Himalayan honeysuckle, Holly, Jasmine (White), Japanese honeysuckle, Lantana, Madeira vine, Montbretia, Pampas grass, Small-leaved and broad-leaved Privet, Red Hot Poker, Seaside daisy, Spanish heath, Tutsan, Trad/Tradescantia fluminensis, Watsonia, Willow (Grey Sallow).
Removal of these common environmental weeds from your garden/property, or even effective management of their flowers and seeds, could greatly benefit the natural environment of the Blue Mountains, especially if you live near a stream, swamp, bushland reserve or Blue Mountains National Park.
As mentioned, for help with identifying and controlling environmental weeds, see the Environmental weeds of the Blue Mountains and Identification, illustrations and control of environmental weeds sections below.
The complete BMCC Blue Mountains noxious and environmental weeds list
Blue Mountains City Council maintains a comprehensive Blue Mountains environmental weed species list. All Blue Mountains environmental weeds are listed. The list was published in BMCC Development Control Plan 2015: Part C Environmental Management, Revision: Amendment 5 (April 2023).
A copy of this list can be found here: BMCC DCP 2015 Weeds List.pdf - please feel free to share it with friends and family.
Two major challenges associated with controlling environmental weeds are:
To assist with these two issues, here are some helpful resources.
For colour weed illustrations, management techniques and garden management advice, consult these BMCC resources: Weeds Information Booklet 2024 and https://weedsbluemountains.org.au.
Weeds Australia (https://weeds.org.au) also provides good advice and illustrations.
Do you need additional identification or management advice? Contact Blue Mountains City Council by email at council@bmcc.nsw.gov.au or phone on 47 80 5000. BMCC Bushcare Officers are available to help with identification and control advice.
The Society’s Bushcare Officer may be able to help with plant identification and advice on weed control (https://bluemountains.org.au/office-holders.shtml).
Professional arborists, bush regenerators and horticulturalists may also be able to offer advice with plant identification and management. They may charge a fee.
Always consult Blue Mountains City Council before undertaking tree management works or major landscaping on your property.
Thank you for considering the environmental weed management advice offered by the Society. Please note that Blue Mountains Conservation Society is a volunteer environmental organisation. Members of the Management Committee are volunteers and do not claim to offer professional standard advice. If in doubt about your particular matter of concern, please seek professional advice.
BMCC (n.d.) Weeds of the Blue Mountains Cherishing our bushland Blue Mountains City Council https://weedsbluemountains.org.au/
CSIRO (n.d.) Biological control of weeds https://www.csiro.au/en/research/plants/water-marine/weed-biocontrol
Duursma, D.E., Gallagher, R.V., Roger, E., Hughes, L., Downey, P.O., Leishman, M.R. (2013) Next-Generation Invaders? Hotspots for Naturalised Sleeper Weeds in Australia under Future Climates. PLOS ONE 8:12 DOI: 0.1371/journal.pone.0084222
Environment and Heritage (2024) Weeds Find out how weeds threaten biodiversity and what we are doing about it Department of Environment and Heritage NSW Government https://www2.environment.nsw.gov.au/topics/animals-and-plants/pest-animals-and-weeds/weeds
Gallagher, R., Leishman, M. (2014) Invasive plants and invaded ecosystems in Australia: implications for biodiversity Chapter 6 in Stow, A., Maclean, N., Holwell, G. (eds.) Austral Ark: The State of Wildlife in Australia and New Zealand Cambridge University Press
Groves, R.H., Boden, R., Lonsdale, W.M. (2005) Jumping the Garden Fence: Invasive garden plants in Australia and their environmental and agricultural impacts CSIRO World Wildlife Fund https://wildlife.lowecol.com.au/wp-content/uploads/sites/25/Jumping-The-Garden-Fence.pdf
Hulme, P.E., Brundu, G., Carboni, M., Dehnen-Schmutz, K., Dullinger, S., Early, R., Essl, F., González-Moreno, P., Groom, Q., Kueffer, C., Kühn, I., Maurel, N., Novoa, A., Pergl, J., Pyšek, P., Seebens, H., Tanner, R., Touza, J. van Kleunen, M., Verbrugge, L. (2018) Integrating invasive species policies across ornamental horticulture supply chains to prevent plant invasions Journal Applied Ecology 55:92–98. DOI: 10.1111/1365-2664.12953
Maher, J., Stringham, O.C., Moncayo, S., Wood, L., Lassaline, C.R., Virtue, J., Cassey, P. (2023) Weed wide web: characterising illegal online trade of invasive plants in Australia. NeoBiota 87: 45–72. https://doi.org/10.3897/neobiota.87.104472
Smith, P., Smith, J. (2010) Urban edge effects in the Blue Mountains, New South Wales: implications for design of buffers to protect significant habitats PACIFIC CONSERVATION BIOLOGY 16: 92–100. Surrey Beatty & Sons, Sydney https://bluemountains.org.au/documents/research/blue-mountains-urban-edge-effects.pdf
Strelau, M., Clements, D.R., Benner, J., Prasad R. (2018) The Biology of Canadian Weeds: 157. Hedera helix L. and Hedera hibernica (G. Kirchn.) Bean Canadian Journal of Plant Science 98: 1005–1022 (2018) dx.doi.org/10.1139/cjps-2018-0009