Regarding the rock attracting attention, that's what I expect as it's the principal component of the competition. You might even consider the tree to be an accent.
Mike,
I concur with Attila, a very interesting and unique composition.
Based on your above explanation, I would consider using a different pot. To me, the pot (the color in particular) compliments the tree rather than the rock. To my eyes, this creates visual confusion.
In general, I think we have been conditioned to view a composition such as this with the tree as the focal point. As I look at your creation, my eye wants to move from the pot to the tree. However, due to the dynamic nature and color of the rock my eye is drawn away from the tree very quickly and this is were the confusion is created for me and the tree is lost.
I would select a textured, round pot with colors similar to the rock. I feel this would help the viewer to focus on the rock first and not cause as much visual confusion.
Just my thoughts.
Thanks for sharing.
Regards,
Paul