Q.Holly Bush
I have a holly bush that is very large, and in December I noticed that it was coming up out of the ground at the roots on the back side and falling forward. I straightened it up and put more soil around it and tied it with rope secured to the deck, which is behind it. Recently, I untied it and sure enough it fell over again. I am trimming it down and will try to replant it. Any further suggestions or ideas as to why this happened? I appreciate your thoughts.

The first thing that came to mind was frost heave. Here is an article that discusses frost heave and how to protect your plants from it: