Dreamfoil
Dreamfoil requires a herbalist to be 270 to gather and is on of the main herbs found in Azeroth and in the earlier zones in the Outlands. Dreamfoil originated from Azeroth and seems to be a very tough plant as it can survive the harsh weather of the Outlands. Dreamfoil is widely spread in level 50 to 60 zones.
See below for efficient routes to farm Dreamfoil.