Hmm... I am sure that you can catch it on Route 37 just before entering Ecruteak City. and also to the east of Celadon city and another to the east of Saffron.
But another resource says that Growlithe is available in Gold, but not in Silver
i also think they are only catchable at night time
Trade
Growlith Issac Lim
You have to have Pokemon fire red for GBA. Catch it on that.Once you have beaten the elite four and finished the Sinnoh Dex (on diamond) the Pal Park will open and you can migrate it from fire red to diamond.
at the safari
Growlithe will evolve when you use a fire stone on it.
You can catch a Growlith in the Pokemon Mansion on Cinnabar Island.
In the Pokemon mansion but only in fire red
you use a firestone on it
Growlithe is found in the Pokemon Mansion on Cinnabar Island in Pokemon Firered.
You could find wild Growlithes in Route 48.
Unfortunately, you cannot catch a Growlithe in Pokemon Leaf Green. You need to trade one from Pokemon Fire Red or XD.
Fire Stone
Im afraid there is no other way except using an action replay cheat cartridge.
Trade
in heart gold you see Ho-oh first soul silver lugia first heart gold has a different starting screen with ho-oh in it soul silver has lugia in the starting screen heart gold lets you catch Kygore and latias soul silver lets you catch groudon and latios heart gold lets you catch growlith, caterpie and spinarak soul silver has vulpix, weedle and ledyba.
you cant.you have to insert Pokemon firered.
Growlith Issac Lim