The White Aster crop is now available to plant, but only for a single week. To be specific, this four-hour crop is only available to plant until July 13. You'll be able to plant a single square for 30 coins, and will gain 2 XP for each square you plant. After four hours, you can come back to your farm to harvest them for 100 coins per square. While this short-growth time makes the crop a bit questionable in terms of overnight planting, you'll at least be able to plant and harvest the Asters multiple times throughout the day to earn those highly sought after Mastery Points.
The first star of Mastery for White Asters is only 300 harvests, so with some dedication, you should be able to completely master this one in time, before it leaves the store.
Will you try to master White Asters before the crop expires in a week? Had you completely forgotten about Zynga's promise to eventually release the crop? Let us know in the comments.