Clasped pondweed

Clasped pondweed is a perennial, entirely submerged aquatic herb with slender rhizomes and roots.

Description

• Stems are two metres long, thin, and greenish/brown.

• Leaves are 7cm long, translucent, alternate and basally wrapped around the stem.

• Flowers are small, green, and appear on spikes between November-January. They are produced on the water surface.

• Fruit is green and smooth.

• Spreads via seed, stem, and rhizome fragments.

• Habitats include flowing or still freshwater bodies, lakes, streams, ponds, and estuaries.

What you need to know

Clasped pondweed can form dense infestations, altering natural habitat structure and blocking waterways. It may hybridise with the native Potamogeton spp.

Management approach

Clasped pondweed is declared an unwanted organism by the Ministry for Primary Industries (MPI) because it is capable of causing harm to the natural environment, physical resources or human health in Aotearoa/New Zealand.

These species pose a high risk to our environment, economy, recreation, and cultural values.

Rules

Any species declared a pest, including unwanted organisms, cannot be sold or be in a place where plants are being sold. Pest plants cannot be propagated, bred, or multiplied, communicated, released, or cause to be released, or otherwise spread.

Control

Do not attempt to undertake control of clasped pondweed yourself. Report any sightings to us.