Spawn Procedural Foilage By Mask File


I use an landscape material (Brushify) with different layers (one for grass, another for stone, and so on). Every Material is a combo of texture and procedural foilage. So grass spawns on grass texture and stone meshes on stone texture. Now i want a layer just for foilage without any texture. At the moment i place different material layers with a mask image file (black/white image) on my terrain. I search for a way to spawn a complet forest or mountain path just by painting white areas in photoshop on some mask image. But i dont want to change the texture and foilage of the other layers under the new “forrest”. So my idea is to create a new layer of my landscape material with invisible texture and only foilage. Could this be a possible way or is there another way to spawn foilage with a mask image file?

Hope someone understand my question and could help me :wink:

best regards