Last year I had some that had migrated into my perennial beds from the nearby woods, and I read that they are difficult to dig out once really established. So, I went after them not long after they bloomed and transplanted them to another woody area that I'm hoping they'll colonize. The roots were kind of like Solomon's Seal-- very thick horizontal tubers, and they were all connected by rhizomes. It was not too bad digging them out, but I can see how you would miss a lot of them if you waited until fall and the stalks were no longer visible. I would try moving them in spring, and just keep them watered 1x per week in the location where you move them (unless you get good natural rainfall). That's what I did last year, and my transplanted ones are doing fine this spring! Good luck.

I've had three or four plants come up for many years down in the orchard. I always thought they spread. Well....this Spring I got my wish but perhaps I won't be as thrilled from now on as I expected to be. Even tho I really enjoy them.