Onehunga weed is a prickly interloper which makes walking on the lawn in bare feet very painful. It is an annual weed and the prickles are part of its seed setting cycle.
It is a very low growing with leaves that are 15-50mm long and finely divided, with a feathered overall appearance.
You can spray for Onehunga weed earlier in the season before the plants flower and set prickles (latest date to spray is approximately labour weekend).
If you have a lush, healthy lawn, it will find it harder to invade the lawn with established grasses.To control it you can hand weed as it has a relatively shallow root system. If it is throughout the lawn, then it can be sprayed with the full rate of a recommended herbicide.