Perennial herb, floating and emergent leaves and flowers. Long, creeping stems, clusters of 5-7 shiny green oval leaves. Leaf has an inflated mid vein on underside. Yellow poppy-like flowers (Nov-Apr) with 3 petals.
Still or slow-flowing water <2m deep. Grows in warm and cool climates. Prefers nutrient rich conditions.
No seed set in NZ. Spread by plantlets or stem fragments. Dispersed by water boats, fishing gear, machinery.
Mats quickly cover waterways, impeding drainage, disrupting recreational activities, choking hydro turbines. Out-competes native species.
Regular follow up required. Clean all boats, trailers, fishing gear etc.
1. Report it immediately to the Auckland Council Biosecurity team, who will arrange for its control at their expense.
2. Line pond with black polythene or weed mat. Lining can be removed 3-6 months.
3. Spray (200ml glyphosate/10L, use glyphosate formulation approved for use over water).
Caution: when using any herbicide or pesticide PLEASE READ THE LABEL THOROUGHLY to ensure that all instructions and safety requirements are followed.