The Olemba root is a fairly common root found in the Terokkar Forest. Search near the Olemba trees that comprise the bulk of Terokkar's forests for upturned roots.
The marshberry only grows in Zangarmarsh. It can only be found at the Ango'rosh Stronghold, located in the northwestern region of the marsh. Beware the ogres that fervently guard the precious berries.
The Telaari frond is perhaps the most easily attainable of the herbs on this list. South of Garadar in the Talaari basin, you will find the fronds. They grow near the water.
The last herb on the list is unique to the Blade's Edge mountains. You will find Blade's Edge north of Zangarmarsh. Dragonspine grows upon the ends of the jagged rock formations that guard the canyons of Blade's Edge. You will know what I speak of when you first see Blade's Edge. The rock formations look like row upon row of sharp and pointed teeth.