It may appear in the Burned Tower or you can find it in the Safari Zone at night.
He's in the old abandoned tower, where HO-OH was last seen
No, it is not wild
you cant catch persian in heartgold.... i think
Gastly are found in sprout tower.
No, you cannot catch Regirock, Regice, Registeel or Regigigas in Pokémon HeartGold, they are not available in the game as wild Pokémon.
Bellsprout tower at night time.
You can't catch a Mew in the wild. You'll need to trade for it or use the Action Replay.
You can't get a wild Gengar, you have to catch a wild Ghastly, or Huanter and evolve it. For more help visit Pokemon.Marriland.com (DISCLAIMER: I DO NOT OWN POKEMON.MARRILAND.COM OR ANY POKEMON TRADEMARKED BY NINTENDO!)
You could find wild Growlithes in Route 48.
You cannot capture your opponents. You cannot capture your opponent's Pokemon, either. You can only catch wild Pokemon.
After you go to burned tower it will appear in the wild randomly. how you catch it is up to you (personally I would use a master ball)
There are no wild bulbasaurs unless you go to the Pal Park and catch a migrated one. You can do this on Diamond, Pearl, Platinum, Heartgold, and soulsilver