Weed Identification
Common Waterweeds and Their Impact
These invasive plants rapidly multiply, forming dense mats that cover waterways, affecting water quality, flow, and wildlife habitats. They pose threats such as increased water loss, mosquito breeding grounds, and oxygen depletion. Mechanical removal is emphasized as the preferred method to curb reinfestation for these declared noxious weeds, each with its distinct characteristics and ecological impact.
WATER LETTUCE
Description
The entire plant resembles a small, floating, open head of lettuce. It rapidly forms dense mats covering the entire waterway.
Issues
Water Lettuce increases water loss, is a breeding zone for mosquitoes and degrades water quality.Control
Mechanical removal is best to eliminate reinfestation.Status
DECLARED NOXIOUS WEED
SALVINIA
Description
Is a free-floating aquatic ferns. They have small spongy leaves in two ranks along a common stem, and a root system that resembles wet hair. Plants can double in volume in 2 - 3 days.
Issues
Salvinia can affect the water quality, water flow, wildlife, irrigation areas.
Control
Mechanical removal is preferred to stop reinfestation.
Status
DECLARED NOXIOUS WEED
WATER HYACINTH
Description
Is a floating water weed with dark green rounded leaves up to 5cm across and a fibrous system, flowers are light purple with a darker blue/purple and yellow centre. An infestation can rapidly double in size every week.
Issues
Not only does it destroy native habitats, but it depletes the oxygen in the water, increases water loss and is a breeding ground for mosquitoes.
Control
Preferred removal is mechanical, to totally rid your waterways.
Solution
DECLARED NOXIOUS WEED
PARROTS FEATHER
Description
Stem spreading and erect, hairless 5m long to 5mm wide, blue/green in colour. It is quite an aggressive growing plant that will spread very rapidly.
Issue
Parrots feather chokes the waterways, damages waterways, reduces water quality.
Control
Mechanical removal of the roots is necessary.
Status
DECLARED NOXIOUS WEED
DUCKWEED
Description
Is the smallest of aquatic waterweed, it is only about 5mm in size and is a free-floating weed, growing in clusters and looks like a green carpet over the water. It is extremely fast growing.
Issues
Duckweed multiplies rapidly. It may spread from pond to pond on the feathers of waterfowl. When duckweed completely covers a pond, it will block light from reaching other plants that live within the pond which in some cases leads to fish kills.
Control
Mechanical removal is required.
Status
NON NOXIOUS WEED
AZOLLA
Description
Is a common floating fern 10-30mm in diameter with roots hanging down 40mm below the water's surface., it is green in shaded areas and reddish in direct sunlight.
Issues
In the right conditions it can double within 7days.
Control
If left the Azolla can block pump inlets and filters, entering into drinking tanks.
Status
Mechanical removal is preferred.
Status
NON NOXIOUS WEED
ALLIGATOR WEED
Description
Have hollow stems, dark green leaves which have a distinct midrib,leaves that have no leaf stalk and white paper-like ball-shaped flowers. The plant grows out from the banks to form floating rafts of dense interwoven stems.
Issues
Alligator Weed restricts water flow, damages irrigation equipment, reduces water quality, habitat for mosquitoes, reduces bird and fish activity.
Control
Mechanical removing from the root system is your only bet to stop reinfestation.
Status
DECLARED NOXIOUS WEED
WATER PRIMROSE
Description
Water primrose is an invasive aquatic species that forms extensive mats, impairing water flow and shoreline activity. It can dominate shoreline vegetation if introduced to lakes, rivers, ponds or streams. It is very difficult to control once established. It is similar to the Alligator weed, however it has yellow flowers.
Issues
Water PRimrose reduces plant and animal diversity as other species are displaced. Poorer drainage flows as mats slow water and accumulate sediment.
Control
Mechanical removal is best to eliminate reinfestation.
Status
NON NOXIOUS WEED
BULLRUSH
Description
Is an erect weed-like perennial growing up to 4m tall. Leaves growing in bunches from below water level, reaching 60cm-3m long. Flowering stems grow erect from the middle of the leaf cluster.
Issues
Bullrush interfere with the water flow, reduce water quality and provides breeding places for vermin and mosquitoes.
Control
Mechancial removal is best, as it needs to be removed from the roots.
Status
NON NOXIOUS WEED
SINGAPORE DAISY
Description
Is a vigorous ground cover it produces yellow, orange/yellow coloured daisies. It is an aggressive growing plant that will spread rapidly.
Issues
This plant will overtake anything and everything if not brought under control.
Control
Mechanical removing from the roots is the only way to control it.