Borage
Also known as
Starflower, Common borage, Burrage
Keep this plant’s care guide close at hand.
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Borago officinalis is a fast-growing, self-seeding annual herb native to the Mediterranean, prized for its vivid blue, star-shaped flowers and cucumber-scented foliage. Plants reach 60–100 cm tall with hollow, succulent stems and rough, bristly leaves that deter herbivory and reduce water loss. Borage attracts bees and other pollinators prolifically, making it a valued companion plant in vegetable gardens. The edible flowers are used fresh as a garnish or frozen in ice cubes, and young leaves can be used sparingly for a mild cucumber flavor. It thrives in well-drained soils, tolerating poor fertility and brief drought once established, though consistent moisture supports lush growth and longer bloom. It grows best in full sun but benefits from afternoon shade in hot climates. While culinary use is common, the plant contains pyrrolizidine alkaloids, so frequent or heavy consumption should be avoided. In containers, provide a deep pot to accommodate its taproot and prevent lodging by spacing adequately or staking in windy sites.
Taxonomy
Properties & Requirements
How to care for Borage
Water
Keep soil evenly moist during establishment, watering deeply to encourage a robust taproot. Once established, allow the top 2–3 cm of soil to dry before watering again; borage tolerates short dry spells but not waterlogged conditions. In containers, water when the top 2–4 cm are dry, ensuring thorough drainage and emptying saucers. Aim for roughly 2.5 cm (1 inch) of water per week outdoors, adjusting for rainfall, heat, and soil type.
Light
Provide full sun (6–8+ hours daily) for the heaviest flowering and compact growth. In regions with intense summer heat, light afternoon shade helps reduce stress and leaf scorch. Indoors or on balconies, place in the brightest location available (south- or west-facing), supplementing with grow lights if necessary. Avoid deep shade, which leads to lanky, flop-prone stems and sparse blooms.
Nutrients
Borage is not a heavy feeder. Mix in compost or a balanced organic amendment at planting to support early growth. Avoid high-nitrogen fertilizers, which promote leafy growth at the expense of flowers. In poor soils, a light application of balanced fertilizer (e.g., 5-5-5) once early in the season, and a compost side-dress midseason, is usually sufficient. Overfeeding can reduce flavor and lodging resistance.
Temperature
Best growth occurs between 15–24°C (60–75°F). Borage tolerates cool weather and light frosts once established but is damaged by hard freezes. In hot climates (>29–32°C / 85–90°F), provide consistent moisture and consider afternoon shade to prevent wilting and premature bolting. It is typically grown as a cool-season or shoulder-season annual, reseeding itself readily where winters are mild.
