Emergent, perennial <80cm high. Fleshy rhizomes usually submerged below surface. Leaves either emergent (ovate, tapering to point on triangular winged stem) or submerged (strap shaped), held above surface by rigid stems. White - pink flowers (Nov-Mar) in clusters of 3-flowered whorls; flowers always below leaf height.
Static or slow moving freshwater <45cm: drains, streams, pond margins.
Locally spread by creeping roots. Seeds carried by water, wildlife, machinery. Rhizome fragments spread by machinery.
Extensive infestations block waterways impeding drainage, disrupting recreational activities. Out-competes native species
Regular follow up required.
1. Report it immediately to the Auckland Council Biosecurity team, which will arrange for its control at their expense.
2. Dig out plants removing all plant material.
3. Spray emergent plants before they flower and seed (200ml glyphosate/10L, use glyphosate formulation approved for use over water).
4. Palatable to grass carp, refer to DOC.
Caution: when using any herbicide or pesticide PLEASE READ THE LABEL THOROUGHLY to ensure that all instructions and safety requirements are followed.