Alligator Flag - Thalia geniculata

Grows in ponds, roadside ditches, swamps and the edges of lakes, dams and other water courses. Plants are not salt tolerant.... more

Alligator Weed - Alternanthera philoxeroides

Amongst the worst aquatic weed threats in Australia. Adapted to growing on damp land, occasionally flooded land, in shallow water (rooted in the substrate), attached to the bank (in deep water) or free floating. Will survive for a few days ... more

Cabomba - Cabomba caroliniana

Probably introduced as an aquarium plant. Widely sold for aquaria. Now amongst the worst aquatic weed threats throughout Australia. Grows in still or slowly flowing water in depths ranging from a few cm to 5 m or more. Dense infestations in... more

Caulerpa - Caulerpa taxifolia

The aquarium strain is apparently male. Native Caulerpa taxifolia reproduces sexually and cannot readily be distinguished from the aquarium strain. The aquarium strain is a major weed in the Mediterranean and an emerging problem in C... more

Celery Leaf Buttercup - Ranunculus sceleratus subsp. sceleratus

Found in shallow pools and intermittently flowing drainage channels where it sometimes impedes flow. Plants are often associated with high nutrient levels. Rosettes appear in autumn. It is generally regarded as the most toxic of the butterc... more

Dense Waterweed - Egeria densa

Prefers slow moving waters and often does not persist in streams that flow vigorously. Mostly in nutrient rich water. Occasionally a problem obstructing water flow; interferes with recreational uses such as swimming, boating and fishing and... more

Elodea - Elodea canadensis

Dense infestations reduce water flow; interfere with recreational uses such as swimming, boating and fishing and outcompete native plants.... more

Eurasian Watermilfoil - Myriophyllum spicatum

Dies back to root crowns in winter and reshoots in spring. Tolerates a broad temperature range, pHs from 5.4–11 and brackish conditions (tolerates salinities up to 15 parts per thousand). In the USA and Canada it forms dense canopies that s... more

Glush Weed - Hygrophila costata

Sold as an aquarium plant. Now a significant water weed in northern coastal New South Wales and south eastern Queensland where it displaces most other species in shallow water and neighbouring damp soil.... more

Hydrocotyle - Hydrocotyle ranunculoides

Dense growth may extend over static or slowly-flowing water. Overwinters in leafy form. First recorded in 1983 near Perth. At one time clogging a eutrophic tributary of the Canning River, Perth. Has potential to spread in nutrient enriched ... more