You'll need to trade for it from Pokemon Silver, or the older GBC games.
No,you can´t. You must trade from an other version.
You can't. In Soul Silver, you can catch a Vulpix but not a Growlithe. In Heart Gold, you can catch a Growlithe but not a Vulpix. I recommend trading a Vulpix (or any Pokemon, really) to someone with a Heart Gold game in exchange for a Growlithe.
You can't catch vulpix in Heart Gold, though you can catch it in Soul Silver. On the small route 37, Below Ecruteak City, you can find: ~Heart Gold = growlithe ~Soul Silver = vulpix (they both evolve using a fire stone)
In Gold, you can only get it through trade. But for Sliver players, you can find it in Routes 7, 8, 36, and 37.
you have to show certain Pokemon to Bill's grandfather to get the evolution stones. To the best of my knowledge they are (in this order); Lickitung, Oddish, Staryu, and Vulpix. now because you can only catch a Vulpix in Silver version and not gold it may be a growlithe instead.
on route 44 you will find him
Outside of Mistralton City.
you can find them in soulsilver gold silver ruby
Its silver dependent aka not available in gold.
It is an event
You have to trade with silver to get, or blue and yellow.
If you have a teddiursa get it to level 30 to evolve it into ursaing