Time to get sick on candy again, folks! That seems to be a running theme with WoW holidays.
Noblegarden will run this year from Monday, April 1 until Monday, April 8. As always, check your server's in-game calendar for the exact start and stop times. If you've never done Noblegarden before, or only done its pre-2009 version, be aware that Noble Gardener (the holiday's meta) is part of the year-long What A Long, Strange Trip It's Been achievement.
Last year, the Swift Springstrider was added to holiday vendors at the fairly steep cost of 500 Noblegarden chocolate. This year, we haven't seen anything new datamined, but Noblegarden did hit the patch 5.2 PTR in mid-February, so you never know.