Heartblossom can be found, well I guess you could say at the heart of Azeroth in Deepholm. Which is located in the middle of the map. To get there all you need is to be level 82 and a small questline consisting of 2 quests will unlock. After completing those quests you will be in Deepholm. Once you are in Deepholm, make sure you have the inventory space for this because you will need it!
I highly recommend at least one Hyjal Expedition Bag, preferably two. If all you have is one that is okay! Make sure you have inventory for around 40-50 stacks. While that is not guaranteed amount of inventory you will use. It’s always nice because you never know when you kill a mob or pick up a chest and there is a nice piece of loot to be yours.
Using this route I was able to pick up 29 stacks of Heartblossom alone. 10 stacks of Cinderbloom. Along with a total of 223 Volatile Life. Making this one of the best herb farms in Cataclysm content. While the herbs don’t sell for much more than 2.50 gold per unit or 50 gold per stack on the Heartblossom. 2.38 gold per unit or around 45 gold per stack on Cinderbloom. The Volatile life is going for less than 2 gold per unit. Making it around 300-350 gold per stack.
This means you will be making slightly less gold per hour on the low prices. However, it is still one of the better farms to do if you have either alchemy or Inscription. There are shuffles I will be writing about in about a week going over these shuffles If I feel they are worth the gold to do.