If you only have a few ragweed plants, try pulling them up, taking care to remove all of the rhizome and root system. If the weed has already spread across your entire lawn, pulling it up by hand ...
Onehunga weed has finely divided leaves, which may get confused with several other weeds found in the lawn. One of these is yarrow, but yarrow is a perennial weed that has a creeping rhizome system ...