Is it Bocking 14 Hank? Bocking 14 does not have viable seeds about a couple of feet between roots will allow it to propagate through runners. If it is a seeding one then I don't think it matters too much. Whatever you do you should be over-run with it in a couple of years. :o))

Not Bocking. Just roots I obtained from near a road. And I want to be over-run.

Marvellous plant ! The White Flower is Comfrey Officionalis, the Purple Flower Comfrey Vulgaris.

I have filled 3 compost bins with it this summer.

Diane - I've written a message to you re your assistance

I am still trying to work out how to spell Ryton-on-Dunsmoor - had to get the road map out . Must be the effects of the weather.
(The Henry Doubleday Research Station.)

Diane,
I've never heard of Ryton-on-Dunsmore, I wonder why you need to ? But if it's in Warwickshire this is correct

Yes, am having difficulty getting P.M. on screen. Henry Doubleday was the original believer in Comfrey as a plant food. He pioneered 18 different varieties and studied them all.
Go into Google and type in The Henry Doubleday Research Station, Ryton-on-Dunsmoor and you should get the information you are looking for.
I have been there on a gardeners' coach trip. The most enormous Currant Bushes I have ever seen.

Thanks Diane, I'll do that.