I made this Liferoot farming guide to help out players who want to farm the herbs instead of buying them from the Auction House. This herb can be found near water ponds, rivers and it's recommmended to have herbalism skill of 150 if you don't want to get herb fragments. Below you will find a list of places where I could farm the most Liferoot.
Darrowmere Lake at Western Plaguelands is simply the best place for this herb. Just go around the outside of the lake and pick every herb you see. You will also find a lot of Stranglekelp inside the lake, pick them if you need it for leveling Alchemy.
Second best place is Eastern Plaguelands, so if there is someone already farming at Western Plaguelends, just go to Eastern.
Northern Stranglethorn is also a great place for farming Liferoot.