Onehunga weed (Solvia sessilis) is named after the suburb in Auckland where it was first found, though it actually originates from South America. It is most recognisable in the summer months by the spiny seeds commonly referred to as prickles that attach easily to bare feet. It is for this reason that most residential lawn owners wish to have it controlled. Control should preferably occur in July and August prior to the seed setting. It generally germinates in autumn growing initially as rosettes and then producing short prostrate stems. The seeds form at the base of these leaves. Onehunga weed will often invade bare patches on lawns after hot dry summers. These areas should be scarified and re-sown in autumn to avoid re- colonisation by this weed species.
- All temperate lawn: Control Onehunga weed using Triclopyr & Picloram ( Tordon Bruskiller, Triumph, Victory) or Bromoxynil & ioxynil & mecaprop. ( Image, Axall) or Clopralid (Versatil) These products are best applied from July to September prior to seed set. Beyond this period the plants will be adequately controlled however the sharp seeds or prickles will already be present and as such will still be a problem to bare feet. Do not use any products that contain Picloram or triclopyr on kikuyu or couch grass lawns. .