Knott's Berry Farm started the program, best I can tell. Now called Knott's Berry Bloom, the event has been expanded and will feature a vast selection of special events, plus plenty of pretty decorations.
Ghost Town will have a new Boysenberry Festival, complete with a full sized replication of Walter & Cordelia Knott’s original roadside Boysenberry Stand where guests may purchase boysenberry plants. How cool! There's also plenty of other live entertainment, special events, and activities planned - Knott's Berry Bloom has expanded significantly for 2014.
Joining the fun this year is Carowinds, which will offer Carowinds In Bloom from April 11th through April 20th. Special events include cooking demonstrations from Johnson and Whales University, live bluegrass music, a kids flower planting zone hosted by the Home Depot and the Topiary Tasting Garden where adult can sip a beverage from one of the State's many local breweries.
Plenty of smaller activities will entertain guests as well, such as visits from the Easter Bunny AND Easter Beagle, an Easter basket creation station, coloring wall and more.
We first mentioned Kings Dominion's Spring Bloom festival a week ago, but they have also since added a large line-up of live entertainment to the celebration. This version seems the least developed so far, at least as far as the offerings are concerned. Kings Dominion seems to be focusing on entertainment and food this year, with plans for expanding in the future.
Shame that other Cedar Fair parks don't open early enough (aside from California's Great America, which oddly is not having a similar celebration) since I think these festivals are a great idea!