Sounds as if the plant has suffered from the winter, and may well now be dying back down to the base - fortunately, though, seems as though you have new growth coming from the roots. You can either wait and see if the top starts growing again, or decide to saw the trunk off and let the new growth take over.

Yes, they often grow back from their bases and will do so very quickly. That large rootball needs to supply something so the resulting regrowth is usually fast.

Thanks Bamboo, you too Fractal