Where is Flower Paradise in Pokemon Diamond?

Answer 1

You have to get the National Dex and go through the Victory Road cave with Marley where that guy was blocking before. Visit Proffessor Oak and afterwards, he'll give you his letter. Place the letter on the rock on Route 224 and the Flower Paradise comes into place.

AnswerFlower Paradise can only be visited after you have obtained the item Oak's Letter through a Nintendo Event or cheat code. Once you have the letter, you must make your way through to Route 224, where you will find a shiny silver rock towards the end of the route. Here you should find Professor Oak. He will briefly talk to you, then ask you who you would like to show gratitude to. After you express your thanks, a mass of flowers will appear and a path to your right will open to reveal seabreak path to Flower Paradise. Shaymin will appear and walk back up the path. If you follow it, you should reach Flower Paradise.
YOU have to buy an action replay for $20.00 at target and there are cheats on gamefaqs.com go to legendary faqs at the bottom