You can't catch them wild. You can only use migrate, trade or GTS to get one. Alternatively, you could hack, but that's not exactly good.
1. you cant catch mewtwo on ruby emerald or saphire<spelling mistake> you can migrate the mewtwo you catch on leafgreen or firered to migrate to platinum
migrate
You can't actually catch him in Pokemon platinum but you can migrate him over to platinum if you have him in another game
ok so you want a treeco then fine but i can show you how to get more ok so we all know that you can't catch treeco in diamond or pearl so which is why on your Pokemon emareld Sapphire or any other game boy game where you can get treeco in have a least five other Pokemon and treeco wihc makes six pokemen then on pearl beat the elite four and unlock migrating ability and the migrate treeco oh and if you want a whole army of treeco start over your game boyonce a day catch six wild Pokemon and a treeco and migrat it remember u can only do it once a day
You have to migrate from EMRALD SAPHIRE OR RUBY on to Platinum :)
you can't catch it but you can get it from a trade or migrate, if you can.
you can't catch it you have to trade or migrate it
You cant. You have to migrate it :)
you cant just catch it in platinum you have to migrate it from emrald,saphire or ruby
migrate from fire red
you can not. you must migrate or trade
no u have do migrate from old versions.