I had a very healthy red bistort in a large pot which I have had for a number of years, it has moved house with us 2 years ago and this year it has looked unbelievable. A couple of days ago, however, we moved the pot to a different position in the garden and it now looks as though it is dying. It's very droopy and the leaves are turning yellow. I think some of the fine roots had started taking root in the ground through the bottom of the pot so by tearing these up, would this have caused its sudden deterioration? Will it grow back again next year?