Emergent, aquatic perennial herb. Stems are creeping or floating, with upright flowering stems. Leaves are < 8 x 3 cm and alternate. Flowers are yellow, < 2 cm in diameter and borne in November – February. Fruit capsule is woody and < 2.7 cm long.
To help protect our environment:
Still and slow-moving water body margins, wetlands, damp ground, pasture.
Seeds dispersed by water movement. Vegetative spread from stem and rhizome fragments, dispersed by water movement. Human-mediated dispersal through contaminated equipment.
Forms dense mats, displacing other vegetation, clogging waterways, impeding water flow and reducing dissolved oxygen levels. May negatively impact native fauna through habitat alteration.
Consider engaging an aquatic pest plant control operator. Contact Auckland Council for control options.
CAUTION: When using any herbicide or pesticide please read the label thoroughly to ensure that all instructions and safety requirements are followed.