Does it depend on what type of bush you are trying to pull out. We tried with this one bush and I have no idea what type it was but it would not budge, this even after we dug it out a good bit.
You tried pulling a bush out of the ground with a truck? I would think that would work. We have many tractors here so we would have used that. Of course we would have dug up the ground first (to get the roots chopped up).
That is what we thought too, before and after we dug about 3 feet down to help the truck out. That bush must have been really old with insane roots, it took a tree guy to come out with a large machine to finally take care of the darn thing!