Rotated a texture after the texture sample

how do I rotated a texture after the texture sample? I am trying to get some more variation in my grass texture, I already have the max textures and want to crate a layer to plant of the same grass texture but rotated, I have tried using anther texture sample with that texture but wont paint, so if I use the same texture sample as the grass but rotate will it work? I am struggling with the math side of it