Article Of The Month
Rogue Weed Alert
Ponds, pools, aquariums and water features are an attractive addition to any home, however, like any regular garden; they can harbour some potentially invasive plants.
Aquatic plants have been introduced for garden ponds and aquariums, but unfortunately, many of these plants pose a major environmental and economic threat to Australia's waterways and water resources. In New Zealand, for example, 75 per cent of all aquatic weeds were imported as ornamental pond and aquarium plants.
Problems caused by water weeds
Many of the imported plants thrive in their new environments and are impacting heavily on our health, economy, environment and recreational activities.
Adverse affects from water weeds include:
• Dangerously interfering with swimmers and boating activities
• Reducing oxygen levels in the water, making it unsuitable for many native fish species
• Preventing native birds and wildlife from using wetlands
• Replacing native plants
• Destroying the visual beauty of the environment
• Drowning livestock
• Increasing water treatments and associated costs
• Blocking irrigation channels and equipment.
How do they spread?
Many invasive aquatic plants colonise waterways after being released from aquariums or backyard ponds. For example, Australia's most widespread water weeds, water hyacinth (Eichhornia crassipes) and salvinia (Salvinia molesta), were both introduced as ornamental plants and have subsequently escaped into waterways.
Most infestations occur after plant fragments enter our waterways either deliberately or by accidental actions, such as allowing ponds to overflow during heavy rainfall events or emptying aquariums or ponds into storm water drains. Plant parts can also be washed into waterways from dams during flooding and may move from one waterway to another on boats or boat trailers.
Which plants pose a risk?
There are many aquatic plants throughout Australia that threaten aquatic habitats. At least 30 water plants species in Australia are declared under State and Territory legislation. Of these, 10 species are banned from sale nationally.
Declared aquatic weeds under the Victorian Catchment and Land Protection Act 1994 (C&LP Act).
| Common name | Scientific Name | Status |
Alligator Weed | Alternenthera philoxeroides | State prohibited weed |
Lagarosiphon | Lagarosiphon major | State prohibited weed |
Water Hyacinth | Eichhornia crassipes | State prohibited weed |
Horsetail | Equisetum spp. | State prohibited weed |
Salvinia | Salvinia molesta | State prohibited weed |
Cabomba | Cabomba caroliniana | Restricted weed |
Within Victoria under the C&LP Act, it is illegal for anyone to buy or offer to buy, sell or offer to sell, display, transport, plant or propagate any declared weed species or parts capable of growing. Prosecution and fines of more than $12,000 may apply for breaches of the C&LP Act.
Protecting the future of your industry
There are a number of simple measures that you can do to minimise the risk of introducing or spreading these aquatic weeds.
Do not try to dispose of State prohibited weeds yourself. Contact your local DPI Weed Alert Contact Officer or call the DPI Customer Service Centre on 136 186.
Do not deposit aquarium plants, water or contents near waterways or drains.
Only source your water plants from reputable dealers and traders, not from markets or website forums. The plants you buy might not only be a potential weed but may also have been grown and harvested illegally.
Learn to identify water weeds and be proactive in reporting suspect plants. To become a Weed Spotter contact your local DPI Weed Alert Contact Officer for further information or call the DPI Customer Service Centre on 136 186.
Check and remove plant material from boats, propellers, engine cooling systems and trailers before entering and leaving waterways.
Help spread the message about aquatic weeds. Tell your members, customers and clients.
More Information.
DPI is keen to work with the Aquatic Trade Industry. For further information contact the DPI Partnership Officer on (03) 5430 4394 or the National Aquatic Weeds Management Group Coordinator on (02) 6640 1618.
