This Classic WoW Herbalism Leveling Guide will show you the fastest way to level your Herbalism profession from 1 to 300.
Herbalism goes well with Alchemy because you can use the herbs you pick and craft potions or elixirs. Make sure to check out my Classic WoW Alchemy leveling guide if you want to level Alchemy. But keep in mind, this Herbalism guide is made to level your profession as fast as possible, so sometimes the herbs you will farm might not be the best for Alchemy.
I recommend trying Zygor's 1-60 Leveling Guide if you are still leveling your character or just starting a new alt. It will help you to reach level 60 a lot faster.
Table of contents:
Classic WoW Herbalism Trainers
You can learn Classic Herbalism from any of these NPCs below. Click on the links to see the trainer's exact location.
You can also walk up to a guard in any city and ask where the Herbalism trainer is. Then the trainer will be marked with a red flag on your map.
Horde trainers:
Jandi in Orgrimmar.- Martha Alliestar in Undercity.
- Komin Winterhoof in Thunder Bluff
- Faruza in Tirisfal Glades.
- Mishiki in Durotar.
- Angrun in Stranglethorn Vale.
- Aranae Venomblood in Hillsbrad Foothills.
Alliance trainers:
Reyna Stonebranch in Ironforge.- Tannysa in Stormwind City.
- Firodren Mooncaller in Darnassus.
- Herbalist Pomeroy in Elwyn Forest.
- Malorne Bladeleaf in Teldrassil.
- Kali Healtouch in Loch Modan.
- Cylania Rootstalker in Ashenvale.
- Telurinon Moonshadow in Wetlands.
- Brant Jasperbloom in Dustwallow Marsh.
- Alma Jainrose in Redridge Mountains.
Classic Herbalism Leveling
Every starter zone is filled with herbs. It doesn't really matter which one you choose.
Herbs in these zones: 
Peacebloom, 
Silverleaf, 
Earthroot
1 - 70
70 - 115
Learn Herbalism Journeyman from your trainer.
Herbs in these zones: 
Mageroyal, 
Briarthorn, 
Stranglekelp
Stranglekelp requires herbalism 85, so you can't pick them right away.
This zone is so big that you can use more than one route here.
115 - 170
Don't forget to visit your trainer when you reach 150!
Herbs in these zones: 
Bruiseweed, 
Wild Steelbloom, Stranglekelp, 
Kingsblood, 
Liferoot
Kingsblood requires herbalism 125, and Liferoot requires herbalism 150, so you can't pick them right away.
You should only go to the red zone/lines after you passed 150.
170 - 205
Herbs in these zones: Kingsblood, Liferoot, 
Fadeleaf, 
Goldthorn, 
Khadgar's Whisker
Khadgar's Whisker requires herbalism 185, so you can't pick them right away.
Stranglethorn Vale
Arathi Highlands
205 - 230
Visit your trainer and learn Herbalism Artisan.
Herbs in these zones: 
Purple Lotus, 
Firebloom
Tanaris
Searing Gorge
230 - 270
Herbs in Hinterlands:
Sungrass, Purple Lotus, 
Ghost Mushroom, 
Golden Sansam
I marked a cave with red X, there are a bunch of Ghost Mushrooms in the cave, but you can only pick them with herbalism skill 245.
Hinterlands
270 - 300
Herbs in Felwood: Sungrass, 
Gromsblood, Golden Sansam, 
Dreamfoil, 
Mountain Silversage, 
Plaguebloom
Felwood
I hope you liked this Classic WoW Herbalism leveling guide, congratulations on reaching 300!