I have a Shaymin and I wanted to know how and if I can change it into sky forme in Black 2. I select the gracidea flower then choose Shaymin but it says "It won't have any effect" help please! ._.
Yes, it is possible.
If you bring a fateful encounter Shaymin to a woman at Striaton City's Pokemon Center, she will give you the Gracidea. If you use the Gradidea on Shaymin-Land in the daytime while Shaymin does not have the Frozen status condition, it with change to its Sky Forme. The Gracidea will have no effect otherwise.