Also known as:
Southern water nymph
Origin: North and South America
Regional Pest Management Plan (RPMP) status
- Unwanted organism
Submerged aquatic. Stems slender, branching and < 90 cm long. Leaves are narrow, opposite or in whorls, toothed and tapered to a blunt or pointed tip. Flowers are small, inconspicuous and borne in leaf axils.
What you need to know
To help protect our environment:
- You must not breed, distribute, release or sell southern naiad. As southern naiad is an Unwanted Organism, these restrictions apply within the Auckland region and across the whole of New Zealand.
Still or flowing freshwater bodies, lakes, stream, ponds, ditches.
Seeds dispersed by water. Vegetative spread from stem fragments. Human-mediated dispersal through movement of contaminated boats and equipment.
Impact on environment
Can form dense infestations, outcompeting native plants and clogging waterways.
Consider engaging an aquatic pest plant control operator to control large infestations. Follow up treated areas each year.
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.