What does it look like?
Eel grass is a submerged, bottom-rooted freshwater plant, found in streams, drains, wetlands, lake margins, ponds and aquariums. It produces long, thick, strap-like leaves that are up to 3 metres long. Leaves are light green to brown, slimy to the touch and don't emerge above the surface of the water.
Both male and female plants exist. Male flowers consist of large pollen-filled sacs produced at the base of mature plants. Female flowers are small and green and produced on the end of a very long, spirally coiled stalk that can extend to the water’s surface. There is no evidence of viable seed production occurring in New Zealand, but it spreads by rhizomes or broken off root fragments.
Why is it a problem?
Eel grass forms dense beds that can grow to a depth of 9 metres, out-competing and displacing native plants. In New Zealand, it’s generally spread through intentional planting. It can block waterways, leading to sediment build-up and flooding, and may affect recreational activities, impede navigation and obstruct water out-takes.
Control methods
For control advice, please contact us on 06 835 9200.
Related links
Management Programme
National Pest Plant Accord (NPPA)
The NPPA is designed to prevent the sale, distribution and propagation of a set list of pest plants (the Accord list) within New Zealand. If allowed to spread further, these pest plants could seriously damage the New Zealand economy and environment.
More informationUnwanted Organism
An unwanted organism is any organism that's capable of causing harm to natural or physical resources (like forests and waterways) or human health. A number of introduced pests in New Zealand are classed as unwanted.
Taxonomies
FamilyHydrocharitaceae
TypePlants
GroupSubmerged
HabitatFreshwater
Management ProgrammeNational Pest Plant Accord (NPPA)Unwanted Organism
