How to Plant, Grow, and Care for Borage

Borage is one of the most enjoyable and easiest annuals to grow, and a must-have for anyone interested in natural, cottage, or potager style gardening. I have been growing borage for more years than I can remember, but I have only ever sown it once! This beautiful herb with its vibrant blue flowers repays me every year with an abundance of self-seeded borage to grow for another year. They are a clear signal that spring has arrived and summer is on its way. 

This year my allotment has been redesigned and cleared to incorporate a larger cut flower garden and I have yet to see a little borage baby. So, it is very apt that I get to share my experience, knowledge, and joy that comes with growing borage as I embark on sowing borage seeds for the second time.

Borage, also known as ‘starflower’, is an upright, bushy annual herb with attractive bright blue star-shaped flowers that stands out in any garden. Bees and butterflies love borage! It can be seen buzzing with bees all summer long. Predatory insects such as hoverflies and wasps also love to feast on the nectar of the borage flower making it a great companion in the vegetable garden.

The flowers of borage have a subtle flavor of cucumber and make a perfect garnish for salads or candied decorations for cakes; but if you really want to impress your guests, try freezing flowers in ice cubes and adding them to cool summer drinks.

What is Borage?

Borage, also commonly known as bugloss and starflower, is a member of the Boraginaceae family of plants along with comfrey, forget-me-not, and alkanet. Its botanical name is Borago officinalis, the term ‘officinalis’ indicating its use as a medicinal herb. 

Native Area

Borage originates in the Mediterranean and has been used since ancient Greek and Roman times for a multitude of medicinal purposes including as an anti-inflammatory and a treatment for skin conditions such as dermatitis.

Starflower oil produced from borage seeds is high in Gamma Lineolenic Acid, also called GLA, and is a common nutritional supplement for women of all ages. As will all medicines it is best to consult with a doctor to determine if they are right for you. Caution should also be used when consuming the vegetative form of the borage plant.

Characteristics

When conditions are right, borage can become a large vigorous plant reaching 24-36 inches tall and 12-24 inches across. Its size and sprawling habit can bully neighboring species, quickly outgrowing them and flattening them with its heavy, flower-laden branches. Provide plenty of space, cane supports, and trim to keep growth in check. 

The flowers are bright purple-blue, sometimes pink, and often blue fading to pink with age.  They have five-pointed petals in a star formation with the points of the green calyx behind the flower visible between each petal. Flowers grow densely in downward-facing clusters.

The stems and leaves are mid to dark green with fine silvery-white bristly hairs, which can be an irritant to sensitive skin. Lower leaves are oval and large, reaching six inches in length, and grow abundantly from the base. Leaves on the main flowering stems are smaller and grow more sparsely. Seeds are black-brown, oblong, grooved on the sides with a little round hat on one end.

Seeds should germinate within seven to ten days in the warmth of early spring, with flowers appearing from June right through to early fall. When plants go to seed, they are finished for the year and begin to die. Borage is often referred to as invasive because of its rampant self-seeding habit. However, the seedlings are easy to identify and remove, so it rarely becomes a major problem.

Borage leaves and flowers are edible and have a cucumber flavor. Both are best used fresh, and younger leaves tend to be less hairy and more palatable. Bees that feed on borage flowers are also believed to produce some of the finest flavored honey.

Borage can be grown in large, deep containers. Locate in a sheltered location, water often, and prune container-grown borage regularly to keep them tidy.

Varieties

Here are some alternative cultivars to common borage. Borago officinalis ‘Alba’, a white-flowered variety, and Borago pygmaea, a perennial, low growing variety with small blue star-shaped flowers.

Planting

Sow borage seed directly outside in spring when all danger of frost has passed. This helps roots establish quickly providing a good ground anchor before they get too top-heavy and blow over. Borage also has a tap root that doesn’t transplant well.

For best results choose a full sun location to grow borage, although it can also tolerate partial shade. Sow borage seed in drills approximately one inch deep and rows twelve inches apart, thinning emerging seedlings to twelve inches between them. Amend the soil with organic matter before planting to enhance water retention, but this is not absolutely necessary. Borage grows well in drought conditions and poor soil. The extra organic matter and moisture retention simply help to establish strong roots and create a more stable borage. Support stems with stakes as they get taller for added wind protection.

Want to get a head start? Sow seeds indoors, one seed per cell, three to four weeks before the last frost date. Plant borage seedlings outside after all risk of frost is over and when they are still quite young.

Growing borage in greenhouses and polytunnels is an excellent way to attract pollinators to vegetable crops grown under cover. Borage can also be grown in large, heavy containers filled with well-drained soil. 

How to Grow

Borage is an easy and enjoyable herb to grow in the garden. Follow our care guide below to keep those borage blooms coming all summer long.

Light

For strong stems and abundant flowers, grow borage in full sun to partial shade with at least four to six hours of sunlight per day. The more sunlight, the more flowers, and more pollinators into the garden.

Water

Although relatively drought-tolerant, borage will benefit from regular watering to develop healthy, strong upright plants. Water deeply with soaker hoses or by hand directing water at the soil. Provide lots of space between them to improve air circulation and reduce the risk of powdery mildew when humidity is high.

Soil

Borage grows best in well-drained soils spanning the whole gamut of sandy, loam, and clay.  It will also grow well in a wide soil pH range, including mildly acidic, neutral, and mildly alkaline. It will always benefit borage to add extra organics to the soil when planting.   

Temperature

Suitable for growing in USDA zones 3-10, borage is tolerant of high and cool temperatures, but it will die back with the onset of frost. Borage will prefer a temperature range of between 60°F and 85°F to perform well (16-29°C).

Fertilizing

Regular fertilizer is not necessary to grow borage. Soil amended at the start of the growing season will provide adequate nutrients.

Maintenance

Borage can become a bit unruly with age, with sprawling stems lying on the ground and no real shape or profile. Keep mature borage trimmed to prevent them from becoming top-heavy and flopping over. Regularly deadhead to encourage more blooms and reduce self-seeding. At the end of the season, dig up and compost the entire plant, removing any seed heads first. This adds lots of rich minerals and nutrients to future compost mulches.

Propagation

Propagate borage from seed either directly outside in the garden or in module cells for planting out later. Sow seeds outside in drills approximately one inch deep and rows twelve inches apart after all risk of frost has passed. Thin emerging seedlings to twelve inches between them. 

Start seeds indoors three to four weeks before the last frost date. Sow one seed per cell filled with general compost and plant out when all risk of frost has passed, and borage are still quite young to minimize root disturbance.

Harvesting

Borage flowers, leaves, and seeds can be harvested and stored. Follow the tips below to help you enjoy borage at its freshest.

Harvest young leaves to add to salads or drinks; mature leaves tend to be tough and hairy. To harvest borage flowers, simply pull flowers as needed. Petals can be removed from the green calyx if desired but not necessary. Bright blue flowers are the freshest with the best cucumber flavor. Harvest seeds heads after flowering and store them for sowing next year and sharing with friends.

Storage

Borage leaves and flowers are best used fresh but will store for a few days in the refrigerator gently wrapped in damp kitchen paper. Flowers can be frozen in ice cube trays and added to summer drinks or crystallized and used as cake decorations. Store seeds in paper envelopes in a cool, dry location.

Common Problems

Borage is easy to grow and usually trouble-free, but just in case, here are a few things to look out for.

Growing Problems

The main growing problem with borage is its untidy and sprawling appearance as it grows bigger. Stems are easily broken once laden with buds and flowers and tend to fall or blow over. To counteract this problem, trim them regularly to keep them in shape and deadhead spent blooms. Provide the herbs with supports to keep them upright.

Pests

Aphids (Aphidoidea), in particular, feed on the sap of new growth. Treat biologically by attracting predatory insects, such as ladybug larvae (Coccinella septempunctata) and hoverflies by planting flowers that attract them into your garden. A quick spray of organic insecticidal soap will kill aphids, as will squishing them with fingers. 

Diseases

Borage can become infected with powdery mildew in hot, damp environments, developing a thick white fungal growth on leaves that inhibits photosynthesis and hinders growth. Foliage eventually turns yellow and dies. Maintain good garden hygiene, removing infected foliage to prevent the disease from spreading and reinfection in subsequent years. Provide adequate sunlight and good air circulation.

Frequently Asked Questions