Collect 10 Doom Weed and deliver them back to Junior Apothecary Holland.
So you can see the predicament that I'm in, [player]. That thing is out there collecting the wrong weeds! I'll make it worth your while to gather what I need. Bring back to me enough doom weed and I'll give you a suitable reward.
It is my understanding that they like to plague the flora near the mass gravesite, to the north of the Brill graveyard. Hurry and be mindful of the gnolls in the area.