My white Japanese anemone is grown in a heavy clay soil in North Norfolk and grows like a weed, embracing all other plants within several yards. For the past 3 years I thought I had dug the whole lot up only for it to return, with even more determination the following year. Unfortunately, I believe, a lot of it,s roots are now entwined within the roots of a slow growing conifer which I don,t want to disturb. I dread to think what it would do if I mulched or fed it!!