Erect perennial herb <1m tall. Square stems arising from creeping rhizomes. Mint-like leaves dark green, opposite, deeply toothed and prominently veined. Tiny white flowers (Dec-Mar) clustered in leaf axils.
Spreads locally with creeping rhizomes, water dispersed seed.
Can dominate the margins of still water bodies. Can invade native vegetation e.g. raupo
Replant area with native species to prevent re-establishment. Follow up for rhizome regrowth.
1. Weed wipe during active growth (50ml glyphosate/1L).
2. Spray terrestrial sites (100ml glyphosate + 20ml penetrant/10L).
3. Spray aquatic sites (100ml 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.