Yikes. Anemones are spreaders, although in time the hosta will probably win out and so the anemone can't do any serious damage to the plant. Still the anemone can spread far and wide and so you should remove it and perhaps plant it elsewhere where you can contain it (like using a plastic edger) Best way is to dig up the entire plant and use a hose to flush out the earth so you can see how the roots are entertwined and untangle them.

Ianna

Thanks Ianna, I will try that.

Or, you can use a paintbrush and paint your anemone with Roundup, being careful only to touch the anemone leaves. Then there is no digging up of the hosta thereby setting it back.

Brenda