For simply playing Bubble Safari, you'll receive a single Unwither for use on your farms. If you play Bubble Safari until you've reached the second area of the game, you'll receive three more Unwither Boosts, for a running total of four. Finally, if you reach the fourth area (or Region) of the game, you'll receive a set of six more Unwither Boosts, bringing the grand total to 10 Unwither potions in all.
Completing all three stages of this promotion will likely take quite a bit of time, so keep playing Bubble Safari whenever your energy has recharged to have the best chance of reaching Region 4 (and earning all of these Unwithers) before the cross-promotion ends.
Have you already reached Region 4 of Bubble Safari, or will you need to spend quite a bit of time playing to finish off this three-part promotion? Sound off in the comments.