An apparatus for forming a hole in ground (10) includes a mounting plate (60) mounted to a loader (80). A probe (11) is coupled with the mounting plate (60) through a hydraulic motor (120) having an output shaft (122). The probe (11) is driven into the ground along the vertical axis by movement of the mounting plate (60) by the loader (80), and an upper portion of the probe (11) is simultaneously wobbled about two axes that are perpendicular to each other and to the vertical axis while the output shaft (122) is rotating. The probe (11) is then moved out of the ground to leave a hole (100) in the ground. To provide a rolling action against the sides of the hole (100), the upper end of the probe (11) is moved about an annular path around the vertical axis while the probe (11) is rotating.