salvia is pretty rare. it does however have many genetically similar "subspecies". In other words, if you find one growing by accident in a garden it is probably related but it's not actual salvia divinorium

"Salvia divinorum is a species of sage (the genus Salvia). There are approximately 1000 species of Salvia worldwide, but Salvia divinorum is the only vision-inducing species known. "


Heres a very useful guide I found.

http://www.sagewisdom.org/usersguide.html