I’m grateful to Jevgenia Milne for connecting us with the following great information about this really useful plant.
A member of the borage family like other comferys and alkanets it produces copious green manure and has edible flowers which are good bee fodder (and yes it’s quite invasive). We knew it was eaten in Turkey but had been struggling to find out how. This link gives detailed information. Plants readily available from the nursery!
I have cultivated Oriental Borrage (Trachystemon orientalis) plants for about 7 years, I found it growing in a garden I maintained in Hackney London. It is easy to propergate by root cuttings, and very easy to grow or dig out. It also flowers twice a year, sometimes the flowers give a show in early spring before the leaves are fully formed, the leaves become quite largeand a bit scruffy, and after cutting back will soon regrow, I am pleased to learn it is edible, I have used it in many planting designs as it grows well in dry shade.
Thank you for all this information in the link.