To get your Flax Plant, open up the Valentine's Day Countdown screen by clicking on the cupid heart with an arrow along the right side of your game screen. Then, click on the "Ask/Share" button beneath the Flax Plant. This will post a message to your wall asking your friends to click and send you a plant, and when they click they will get a plant for themselves. Sharing is definitely caring, after all! There are two more items available in the 12 day countdown, and if you collect them all you will unlock a special prize as well.
Have you been collecting all the items in the Valentine's Collection or are you skipping out on this one?