General description

Submerged perennial aquatic. Stems are slender, brittle, branched and prickly. Leaves are triangularly toothed, prickly, < 45 mm long and opposite or in whorls of three. Flowers are tiny, green and borne in leaf axils. Achenes are plump and olive green/reddish.

What you need to know

To help protect our environment:

  • You must not breed, distribute, release or sell sawtooth. As sawtooth is an Unwanted Organism, these restrictions apply within the Auckland region and across the whole of New Zealand.

Saline and freshwater bodies, ponds, lakes, reservoirs, slow-moving streams

Seeds dispersed by waterfowl. Vegetative spread from fragments. Human-mediated dispersal through movement of contaminated ballast water.

Forms dense mats, outcompeting and displacing other vegetation. Clogs and impedes access to waterways.

Site Management

Consider an aquatic pest plant control operator.

Recommended approaches

Physical control

Method: Rake up and pull out between November and January

Plant parts requiring disposal: All parts

Disposal options: Leave onsite to rot down away from the water


Biocontrol is currently not available for this species.

Community agrichemical control recommendations

Certified Handler/Experienced agrichemical user
Follow up in summer after pulling out plants with a foliar spray of 100 ml glyphosate green per 10 L of water

CAUTION: When using any herbicide or pesticide please read the label thoroughly to ensure that all instructions and safety requirements are followed.

Search tags

RPMP status

Unwanted Organism
Sawtooth - Main species image