Plant 246

Borago officinalis L. (Boraginaceae)



Borago gives its name to the Boraginaceae, a family that includes the forget-me-nots (Myosotis), lungworts (Pulmonaria) and comfreys (Symphytum). The origin of the generic name is disputed but may be derived from the Latin for a shaggy coat (burra), a reference to the stiff, white hairs covering most parts of the plant.

Borage is an annual Mediterranean and southern European species that has been grown for hundreds of years in British and northern European gardens for its culinary, medicinal and attractive qualities.

The leaves have been eaten for their cucumber-like flavour, whilst the flowers are sometimes used to garnish summer drinks or are candied for decorating confectionary. The seventeenth-century polymath John Evelyn considered sprigs of borage in wine 'of known Vertue to revive the Hypochondriac, and chear the hard Student'.

The epithet officinalis indicates the plant's traditional use as a medicinal plant. Its former widespread use in early modern medicine has been revived by modern practitioners of alternative therapies. Oil extracted from borage seeds is the richest known source of gamma-linolenic acid (GLA), but the claimed therapeutic benefits of GLA for a wide range of conditions are disputed. Borage also contains very small amounts of hepatotoxic pyrrolizidine alkaloids, which may reach dangerous concentrations in other members of the Boraginaceae.

Individual borage plants are capable of producing huge floral displays. Each nodding flower is about two centimetres in diameter with five blue-white petals that are fused together and arranged in a star-like manner. At the centre of each flower is a dark 'cone' formed from five dark-coloured anthers that are held tightly together. Inside the cone is the style and stigma.

Flowers are arranged in long, curled spikes that have the appearance of a scorpion's tail. A few flowers mature at the base of each spike as the 'tail' unfolds. Consequently, borage flowers throughout the summer and even into early autumn. Early in their development, borage flowers are red, only becoming blue with age. The colour change is thought to be associated with the plant's pollination strategy.

Insects, particularly bees, pollinate borage and are attracted to a nectar reward. Pollen is released by each flower before the female style is mature, a mechanism likely to promote outcrossing. However, because each individual plant has a protracted flowering time, pollen is readily transferred within individuals. Consequently, much of the seed on single borage plants will be the product of selfing, and hence inbred.

Further reading

Jank B and Rath, J 2017. The risk of pyrrolizidine alkaloids in human food and animal feed. Trends in Plant Science 22: 191-193.

Montaner C et al. 2001. Geitonogamy: a mechanism responsible for high selfing rates in borage (Borago officinalis L.) Theoretical and Applied Genetics 102: 375-378.

Stephen Harris