This stand of Comfrey forms a hedgerow of sorts. Probably our native Symphytum x officinale or so-called Russian Comfrey which is the hybrid of S. officinale and S. asperum.

 Russian Comfrey is said to be sterile and non-invasive which I don't think is true because it can certainly be prolific. Russian Comfrey aka Symphytum x uplandicum must be pretty variable because the twenty one 'Bocking' strains were derived from it. I suspect it continues to merge and mutate. 

 Only Bocking 4 and 14 are propagated these days. Possibly the distinctions are meaningless by now. Anyway, the bees don't mind...