Borago is a small genus of five herbaceous species in the family Boraginaceae (order Boraginales), native to the southwestern Mediterranean region. The genus is best known through its single widely cultivated member, Borago officinalis (common borage), which has become naturalized across much of the temperate world.
Plants in this genus are annual or perennial herbs with alternate, bristly-hairy leaves. The inflorescences are branched scorpioid cymes — a coiled arrangement in which successive flowers open along a spiral, reminiscent of a scorpion's tail. The five-petalled corollas are actinomorphic (star-shaped) and typically a vivid blue, rarely white. Stamens protrude through short, notched throat scales and bear mucronate anthers with long pointed appendages. Fruits are obovate nutlets 7–10 mm long, equipped with a thick ring-shaped collar at the base; seeds are dispersed by ants.
The genus is divided into two subgenera. Subgenus Borago groups the erect species with wheel-shaped flowers, including B. officinalis, B. trabutii (endemic to the High Atlas of Morocco), and B. longifolia (endemic to northern Algeria and Tunisia). Subgenus Buglossites comprises the prostrate species with brighter, bell-shaped flowers: B. pygmaea, occasionally grown in gardens, native to Corsica, Sardinia, and the island of Capraia; and B. morisiana, restricted to the island of San Pietro in southwestern Sardinia. Phylogenetically, Borago is monophyletic and closely related to the sister genus Symphytum (comfreys).
Borago officinalis has a long history of human use. Its large hairy leaves carry a mild cucumber flavour and are eaten raw in salads or cooked as a vegetable. The star-shaped blue flowers are used as a garnish, added to wine and cold drinks, and have been a source of GLA-rich seed oil. The plant is a valuable bee forage plant and is widely grown as a companion plant in gardens.
Etymology
The name Borago is of uncertain origin; it is thought to derive from the Latin borra (rough hair or cloth), alluding to the stiff bristly hairs covering the plant, though an Arabic origin via abu araq (father of sweat, a reference to its diaphoretic use) has also been proposed.
Distribution
The genus is native to the southwestern Mediterranean, with four of its five species endemic to a restricted arc spanning northwest Africa (Morocco, Algeria, Tunisia), Corsica, Sardinia, and the Tuscan Archipelago. Only Borago officinalis has escaped this range; cultivated for centuries, it is now naturalized across the temperate world including Europe, the Americas (Argentina, Canada, Chile, Mexico, Paraguay, United States), and beyond. It is probably of North African origin, sharing its native range with the other members of the genus.
Ecology
Species of Borago grow in cultivated ground, disturbed rocky habitats, and scrubby areas typical of the Mediterranean basin. The flowers are highly attractive to bees and other pollinators; the star-shaped blue corollas and exposed anthers are well adapted for pollinator access. Seeds bear a lipid-rich elaiosome and are dispersed by ants (myrmecochory). The stiff bristly hairs covering the foliage are thought to deter generalist herbivores.
Cultivation
Borago officinalis is a fast-growing, largely self-seeding annual that thrives in full sun and well-drained, moderately fertile soils. It is grown as a culinary herb (flowers and leaves), a companion plant said to benefit tomatoes and strawberries, and commercially as an oilseed crop for its gamma-linolenic acid (GLA)-rich seed oil. Borago pygmaea is a prostrate perennial occasionally grown as an ornamental ground cover. Plants tolerate dry conditions once established and self-seed freely, often naturalizing in gardens.
Cultural Uses
Borage has been valued since antiquity. Ancient and medieval herbalists attributed mood-lifting and courage-giving properties to the plant — a tradition recorded since Roman times — and it was added to wine for this purpose. The cucumber-flavoured leaves and edible blue flowers have long been used in salads, cold drinks (notably Pimm's), and as crystallized cake decorations. Medicinally, borage leaf tea has been used as a diaphoretic and expectorant, while the seed oil is a commercial source of GLA used in dietary supplements.
