Particles they fly over the mesh I have an uneven shape and on it I would like to "plant" the grass, but it comes out so that one grass flew in the air and the other grows well.

I would like to get the effect of growing from mesh grass.
I think it is because your using a group. If you make each different grass blade an individual object and gave each of them a different particle system, you may avoid grass that floats in the air.