In Terokkar Forest there is a subzone at 22.10~ called The Barrier Hills which is only reachable with flying mount.
Everytime I go there I find 3-4 Mana Thistle and spot a few Adamantite.
The respawn isnt very long so if you got nothing to do as Miner or Herbalist go there and check once in a while.
EDIT: While writing this thread 2 of them had already respawned
----(please leave the copyright info below intact)----
This post is copyright by the user posting it and MMOwned.com - World of Warcraft Exploits,Hacks, Bots and Guides, where it was posted. You may not copy or reproduce the above on any other site without written permission from both the poster and MMOwned.com