Southern Councils Group - Logo

Alligator Weed

Alligator weed (Alternanthera philoxeroides) is declared noxious in the Illawarra District Weeds Authority control area (including Kiama, Shellharbour and Wollongong council areas).

The weed control class is 2. This means that:

"The plant must be eradicated from the land and the land must be kept free of the plant".

Description: Alligator Weed is regarded as one of the world's worst weeds. It grows as a floating aquatic or as a rooted terrestrial plant. It is a rhizomatous herb. The plant spreads from rhizomes and from stem fragments. Stems are hollow. Leases are opposite, 2 to 7 cm long and 5 to 40 mm wide, gently tapering to the tip and base. The rhizome develops with very close nodes in soil, but longer inter-nodes in water. Flowers 1.2 to 1.4 cm in diameter, are white and paper-like, on 2 to 7 stalks from the leaf axil. Rarely if ever seeds.

Problem: Very invasive. Can completely choke waterways, deoxygenating water and excluding light. Death of aquatic life can result. Can seriously restrict navigation. Occasionally planted in the belief that is the herb Mukunawanna, otherwise known as Ponankaarni. Mukunawanna is legal, tastes much better and does not have side effects as does Alligator Weed.

Control Plan: Click here

For more detailed information click here

Must be reported to the Local Control Authority. Seek their advice.