Thank you for your hints,
@Hetty. They are much appreciated. I will find a spot to anchor it to the ground. The pot sits near an expansion joint on the driveway. I think it will anchor there perfectly!
A dormant tree is not this much trouble!
The soil sits about 6"- 7" below the rim of the pot. I will wait til next year, lift the plant, trim the roots and add more soil below it. This is the tree from my dear friend who has passed away. I cherish it. If DH had run over this one, he wouldn't be here to tell about it!