Grass Output - How do I make it so its only on grass texture?

Hi here are a couple pictures to help explain. First one is the landscape showing grass on the sloped “Rock” which i don’t want to happen. The second is my Landscape Material with Grass Output on where I thought it should go. I have moved it around to other nodes and pretty much get the same or worse results. I’d love some suggestions.

Desktop 5-14-2016 2-19-38 PM-602.jpg

any luck with solution bro ? :d