If the ground can not be pierced, you can not "plant" the pole into the ground as required by the magical item.
The item description does not clarify whether this requirement is about pulling power out of the ground, a & # 39; la "Using the natural power of the earth"or if it's just about keeping the pole upright. In the latter case, a DM would probably allow it to be easily set up with a stand or other object. In the first case probably not.
Ultimately, you have to ask your DM how they would govern in this situation. The fact that this technique can lead to a relatively powerful magic element not being able to use its signature function may be enough to create an exception or at least work around it. On the other hand, sometimes it's okay to have situations where a magical item does not work.
In my opinion, it is probably okay to have the pole set up with only a stand or other object. However, this is not necessarily the perspective of your DM.