’ Where exposed, a GEC ( grounding electrode conductor) or its enclosure shall be securely fastened to the surface on which it is carried. A 4 AWG or larger GEC shall be protected where exposed to physical damage.’ NEC 250.64(B)
That ‘stake’ is also referred to as the grounding electrode.
Unless the rod is longer than 8’ the top should be flush or beneath the surface. The conductor should have straps to hold it to the surface of the building.