Noriel has an idea for making the woods near the river less attractive for the Rohirrim trespassers from Stangard.
'If you are looking to discourage our southern neighbours from wandering so far north, ${PLAYER}, I have an idea for you.
'There is a weed that grows along the river-banks of the Anduin, and its leaves smell quite terrible when crushed. We Elves do not disturb these plants. If you find any, however, it might benefit our cause to befoul the air with their odour. Do you not agree?'
Reek-weeds grow along the river-banks of the Anduin to the north of Thinglad.
You should crush reek-weed leaves along the river-banks to help dissuade the fishermen from setting up camp there.
Noriel can be found in the watch-post Haldirith in northern Thinglad.
You should return to Noriel and tell her that many horrid smells have been unleashed upon the forest.