It is only during the last 70-80 years that it has "escaped" from gardens to become well naturalised, although is rarely found far from houses. (Such recently established plants are termed neophytes as distinct from archaeophytes such as the Greater Celandine - see blog for 2 May, 2013 - which are plants established in Britain prior to the 16th century.) In Druce's flora, published in 1930, it was described as "rare" but now it is very widespread.
|Green Alkanet, Pentaglottis sempervirens|
Byfield, 10 May, 2013
It is a complicated story but... True Alkanet is Alkanna tinctoria, which, like Green Alkanet is a member of the Borage Family. As the word 'tinctoria' indicates it was - and is - used as a dye plant. It provides purple dyes and has also apparently been used as an alternative source of henna. The true Henna is Lawsonia inermis but the word 'alkanet' is derived from the Arabic al-henna - the henna. Green Alkanet apparently yields a red dye.
Whatever the plant may be used for elsewhere, I suspect it won't be gathered around Byfield for dyeing; here we will simply enjoy its brilliant azure flowers over the next few weeks.