Borage - Care Sheet

Borago officinalis
Updated 2025-10-16 18:41 UTC

Overview

Borage (*Borago officinalis*) is a charming annual herb native to the Mediterranean region, prized for its bright blue star-shaped flowers and edible, cucumber-flavored leaves. It grows to about 50–90 cm (1.5–3 ft) tall with rough, hairy foliage and is a favorite in cottage gardens, vegetable patches, and pollinator-friendly spaces. Borage is easy to grow, attracts beneficial insects like bees and butterflies, and self-seeds readily, often returning year after year without replanting.

Quick Facts

Scientific nameBorago officinalis
Common nameBorage, Starflower
DifficultyBeginner
Pet-safe?Yes (generally safe; avoid large quantities due to pyrrolizidine alkaloids)
LightFull sun to partial shade
WaterModerate; allow soil to dry between watering
HumidityAverage garden humidity
Temperature18–29°C (65–85°F); hardy in USDA zones 3–10
SoilWell-draining, average garden soil
FertilizerLight feeding with balanced fertilizer
RepottingNot typically required; self-seeds outdoors
PropagationBy seed, sown in spring

Light

Borage thrives best in **full sun** but tolerates partial shade, especially in hotter climates. A minimum of 6 hours of direct sunlight daily will promote vigorous growth and abundant flowering. In shadier spots, expect leggier plants with fewer flowers.

Water

Water borage moderately, allowing the soil to dry out between waterings. It tolerates some drought once established but performs best with consistent moisture. Avoid waterlogging or soggy soil, which can cause root problems.

Humidity

Borage does well in typical outdoor humidity levels and does not require special humidity conditions. It is hardy in a range of garden environments, from dry to moderately humid.

Temperature

Ideal growing temperatures range from **18 to 29°C (65 to 85°F)**. Borage is hardy in USDA zones 3 to 10, tolerating mild frost but growing most vigorously in warm weather. It is an annual, so it completes its life cycle in one growing season.

Soil & Potting

Borage prefers **well-draining, average garden soil** with moderate fertility. It tolerates poor soil but will grow best in soil with good organic matter content. While it can be grown in containers, borage usually thrives better when planted directly in the garden where it can self-seed freely.

Feeding

Borage is not a heavy feeder. Apply a **balanced, all-purpose fertilizer sparingly** during the growing season to support healthy foliage and flowers. Over-fertilizing can lead to excessive leaf growth at the expense of flowers.

Repotting

Repotting is generally unnecessary for borage grown outdoors, as it is an annual herb that self-seeds readily. If grown in containers, repot young plants into larger pots as needed during early growth to avoid root crowding.

Propagation

Borage is easily propagated by **seed**, which should be sown outdoors in spring after the last frost. Seeds germinate quickly in warm soil and seedlings establish rapidly. The plant self-seeds prolifically, often returning year after year without replanting.

Common Problems

Powdery Mildew

This fungal disease can appear as white powder on leaves during humid conditions. Improve air circulation, avoid overhead watering, and remove affected leaves to control.

Root Rot

Caused by waterlogged soil, root rot leads to wilting and yellowing leaves. Ensure well-draining soil and moderate watering to prevent.

Leaf Spot

Dark spots on leaves may indicate fungal infection. Remove infected foliage and avoid wetting leaves during watering.

Pests (Aphids, Slugs)

Aphids and slugs can damage young plants. Use organic insecticidal soap for aphids and handpick or use barriers for slugs.

Toxicity & Pet Safety

Borage is **generally safe for pets** in small amounts. However, it contains small quantities of pyrrolizidine alkaloids, which can be harmful in large doses. Avoid feeding large amounts to pets, and monitor for any adverse reactions.

Seasonal Care

Sow borage seeds in spring once the soil warms. It grows actively through summer, flowering from early summer until the first frost. Deadhead spent flowers to encourage continuous blooming and prevent excessive self-seeding if desired. In cooler climates, borage will die back after frost; collect seeds for next season or allow natural reseeding.

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