Flower Paradise is a location in Sinnoh and is the only place where players can catch Shaymin. It is only accessible when the player gets Oak's Letter, which in turn is obtained through a Nintendo Event or Mystery Gift. It is found at the end of Route 224 near the "mirror rock". Before players get to Flower Paradise, they must answer a question Professor Oak asks them. After answering the question, the desolate area the player was on then flourishes with flowers and a pathway is opened. When the player follows that pathway, they will finally see Flower Paradise and Shaymin at the end of it. Once you have opened up the Seabreak Path, you will be able to return to Flower Paradise whenever you want.
Shaymin at the Flower Paradise