You have to get the National Pokedex and go past the battle tower and on your way there you will find a cave with Groundon in it.
talk to everyone in the whole game to get a groundon.
You need to import it into the pal park
You can't get him.you have to catch him from palpark or trade from Pokemon soul silver
trade diamond from Pokemon diamond onto Pokemon pearl
You trade Magmar from Pokemon pearl,diamond,or platinum to ether Pokemon pearl,diamond,or platinum.
You can't Find Him on Pearl he can be traded from Heart Gold or Soul Silver but you can't catch groundon on Pokemon pearl i hope i helped. :)
You have to send migrate it from Ruby, Sapphire, or Emerald Pokemon games to the pal park.
THE POKEMON THAT ARE NOT FOUND IN DIAMOND AND PEARL ARE:MANAPHY PHIONE
diamond
You can get Palkia in Pearl, otherwise you have to transfer Palkia from Pokemon Pearl to Pokemon Diamond.
No, you can't catch Deoxys on Pokemon Diamond & Pearl unless you have cheats. You can transfer it from your GBA to Pokemon Diamond and Pearl though
some of the Pokemon are different such as diamond has dialga and pearl has palkia some of the Pokemon are different such as diamond has dialga and pearl has palkia