Grass is covering roads on my map

Hello everyone,

I've been following various tutorials today about how to create a map and I've gotten rather quite far with it but I'm stuck.

The problem is that when I used the ground cover tool the grass goes all over the roads and up the rock faces.
https://i.imgur.com/qVuB9EJ.jpg
I followed a video showing that you can add a layer (i.e the grass texture) to make the grass not be placed on anything else, however, this didn't work.

Any help will be greatly appreciated.
Chuck
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Mods please disregard as I've worked it out. It was incompetence