Sawtooth

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.

Habitats

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

Dispersal

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

Impact on environment

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

Control

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 on site to rot down away from the water.

Biocontrol

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.