Comfery part five. There are several kinds of Comfrey with true blue flowers. This is Symphytum asperum. Sometimes called Rough Comfrey or Prickly Comfrey but it's no rougher or pricklier than other forms of Comfrey.

 

NB Rough Comfrey probably provides the delicate blue wash in the flowers of Symphytum 'Hidcote' which is said to be the hybrid S. officinale x asperum x grandiflorum.