Dug out one of the emerging comfrey plants - this was a solid row. They are Bocking 14 and do not reproduce from seed; therefore it does not take over. In fact, in my heavy clay soil, they behave quite nicely.
The plant yielded 4 crowns (the ones with leaves) and 14 root cuttings a little bigger in diameter than a pencil. This is what it looked like on planting day.
A week later the crowns are already showing new growth, although not top growth from the roots yet. I don't have the doors on my little cattle panel hoop house, but it does keep the wind off of them.
A week later and you can't even see where I dug up the plant. Leaves on the ones in cups are still small, but the leaves on the ones in the ground are quite a bit bigger. In a few more weeks the leaves in the ones in the ground will be longer than my hand and then by summer will be almost as long as my arm.
This is what one of the crowns looked like when I went to check root growth. Totally amazed and happy -- can't believe this is less than two weeks since this bit of crown went into cups.
Potted them up. Hopefully they will grow even better root systems. I know I am giving away at least two of these plants. Do I sell the rest? Plant them in a circle around a tree? Or? So many options that last night I dug another plant from a different area and made more. Hopefully I will see top growth from my root cuttings in the next few weeks.