You have to save at the Troufy garden then talk to Mister Blacklot and if he dosen't say theres a Ditto in his garden turn off the game and talk to him again I hope this helps!!!
You go to mr.backlot (the guy in the mansion under heart home city) and SAVE YOUR GAME before talking to him if he says ditto is in his garden the butler will put it there but he might say things like *there really are cute MIME JR* in my trophy garden just reset and talk to him until he says the envious things press yes on both yes or no questions remember reset if he says there are no DITTO in his garden (hope this helped)
Go to mr backlot talk save before you talk to him then he will say what pokemon is in the garden
example: Evee,ditto etc (hope it helped) 5% for a ditto
example: Evee,ditto etc (hope it helped) 5% for a ditto
Ask Mr.Backlot ONCE a day until he says he has Ditto in his trophy garden.Or go in the trophy garden and use da POKE RADAR
Go to da grass in route 39
In the trophy garden when you get national pokedex.
Poke radar in the tall grass on rote 218
I migrated mine from fire red