Borage

An annual herb with star-shaped blue flowers and cucumber-flavored leaves that is an exceptional pollinator attractor. Sow seeds directly in the garden as borage develops a deep taproot and does not transplant well once established. The edible flowers make a stunning garnish for salads, cocktails, and desserts, and can be frozen in ice cubes for summer drinks. Borage self-seeds prolifically, so a single planting often provides years of volunteer plants with minimal additional effort.

Sow borage seeds directly outdoors 2-3 weeks before the last expected frost, as the taproot makes transplanting difficult. Plant seeds half an inch deep in moist soil, spacing 12 inches apart. Seeds germinate rapidly in 5-10 days at soil temperatures above 50°F. For succession harvests, make additional sowings every 3-4 weeks through early summer. If starting indoors is necessary, use deep biodegradable pots to minimize root disturbance and transplant before seedlings become rootbound.

Sow borage seeds directly in the garden 2-3 weeks before the last frost date, as the plants develop a deep taproot and do not transplant well. Plant seeds half an inch deep and 12 inches apart in rows or broadcast in patches. Seeds germinate quickly in 5-10 days when soil temperatures reach 50°F or above. Thin seedlings to 18-24 inches apart, as mature plants can become quite large, reaching 2-3 feet tall and wide.

Borage is remarkably easy to grow and thrives in average, well-drained soil with full sun to light shade. It tolerates poor soil and mild drought once established but produces the lushest growth with moderate watering. Avoid rich, heavily fertilized soil, which causes weak, floppy stems that require staking. The bristly, hairy foliage is deer-resistant and rarely troubled by pests.

Borage is a prolific self-seeder, and a single planting will produce volunteer seedlings for years. To prevent unwanted spread, deadhead spent flowers before seeds drop. The plant is an annual that completes its life cycle in one season, but successive sowings every 3-4 weeks from spring through early summer extend the harvest of fresh leaves and flowers well into autumn.

Borage is one of the best companion plants in the garden, attracting a wide array of pollinators and beneficial predatory insects with its abundant nectar-rich flowers. It is a legendary companion for tomatoes and strawberries, reportedly improving their flavor and vigor while deterring tomato hornworms. Plant near squash and cucumbers to boost pollination. Borage also accumulates minerals from deep soil through its taproot, making it a useful addition to compost when plants are pulled at season's end.

Borage thrives in average, well-drained garden soil and actually produces more flavorful leaves and abundant flowers in soil that is not too rich. A pH of 6.0-7.0 is ideal. Avoid heavy clay soils where the taproot may rot; amend clay with sand and compost for drainage. Little to no supplemental fertilization is needed. A light side-dressing of compost at planting is sufficient for the entire season. Over-fertilizing produces rank, leggy growth with fewer flowers and less concentrated flavor in the leaves.

Ideal Temperature

Hardiness Zone Compatibility

Harvest young borage leaves when they are small and tender, before the bristly hairs become coarse. Pick individual flowers as they open for the freshest flavor and most vivid color. Use scissors to cut flower stems cleanly. Borage flowers are best used immediately after picking, as they wilt quickly. For leaf harvests, select the youngest leaves at the top of the plant; older leaves develop rough, hairy textures. Continuous flower picking encourages the plant to produce more blooms over a longer period.

Storage & Preservation

Borage is best used fresh, as both leaves and flowers lose their delicate cucumber flavor when dried. Freeze individual flowers in ice cube trays filled with water to create decorative ice cubes for summer drinks. Fresh leaves can be blanched briefly and frozen for later use in soups and stews. Borage flowers can be candied by brushing with egg white, coating in fine sugar, and drying on parchment paper for an elegant dessert garnish. Borage seed oil, pressed from mature seeds, is rich in gamma-linolenic acid and can be stored in dark bottles in the refrigerator.

Troubleshooting Common Problems

The biggest challenge with borage is managing its enthusiastic self-seeding; deadhead flowers before seeds drop if you want to control spread. Mature plants can become top-heavy and flop over in windy conditions or after heavy rain. Provide a supportive companion plant nearby or install a low peony ring for support. The bristly hairs on leaves can irritate sensitive skin, so wear gloves when harvesting. In excessively rich soil, plants grow lush but produce fewer flowers and more susceptible to powdery mildew.

Growing Tips

1. Always direct-sow borage seeds rather than starting them indoors. Borage develops a deep, fragile taproot that resents disturbance — transplanted seedlings often fail to thrive or bolt prematurely. Sow seeds 1-2 cm deep directly where you want the plants to grow.
2. Give borage plenty of space. Mature plants reach 60-90 cm tall and 45-60 cm wide, and overcrowded plants become floppy and prone to mildew. Space plants at least 30-45 cm apart, and consider placing them at the back or edges of beds where their size will not shade smaller herbs.
3. Plant borage alongside tomatoes, strawberries, and squash for companion planting benefits. Borage attracts pollinators that improve fruit set, and its flowers draw beneficial insects like parasitic wasps that prey on common garden pests including tomato hornworms and aphids.
4. Harvest young leaves when they are under 10 cm long for the best flavor and texture. Older leaves become tough, excessively hairy, and slightly bitter. The youngest leaves at the growing tips have the mildest cucumber flavor and the softest hairs.
5. Pick borage flowers in the morning after dew has dried for the freshest blooms. Gently grasp the blue star and pull it backward to separate it from the hairy calyx. Use flowers immediately in salads and drinks, or freeze them in ice cube trays for later use.
6. Allow some flowers to go to seed if you want borage to return next year. Borage self-sows generously, and volunteer seedlings are often more vigorous than intentionally planted ones. Simply thin unwanted volunteers in spring and transplant the rest at the seedling stage if needed.
7. Stake or support tall borage plants in windy locations or rich soil where they tend to grow lanky. A simple ring of twine around a few bamboo stakes prevents the heavy, water-filled stems from flopping over after rain or during strong winds.
8. Grow borage in containers using pots at least 30 cm deep to accommodate the taproot. Use well-draining potting mix and water regularly, as container-grown borage dries out faster than garden plants. Dwarf varieties are particularly well suited to container culture.
9. Make successive sowings every 3-4 weeks from spring through midsummer to ensure a continuous supply of tender young leaves. Older plants become coarse and focus energy on flowering, so fresh plantings maintain the best leaf quality throughout the season.
10. In hot summer climates, grow borage as a cool-season crop in spring and fall rather than midsummer. Plants bolt quickly and produce fewer flowers in sustained heat above 30°C. A fall sowing in zones 8-10 can provide fresh borage through winter.