How to Grow Borage

Borage flowers

The Spruce / Marie Iannotti

Borage is an easy, fast-growing annual herb with vivid blue flowers and the flavor and scent of cucumbers. While it is considered an herb, it's often grown as a flower in vegetable gardens where it is considered a good companion plant for tomatoes, squash, and strawberries. It’s even supposed to deter tomato hornworms and improve the flavor of tomatoes growing nearby.

It's rare that you find an herb that is as beautiful as it is delicious, but borage does the trick. Commonly planted in vegetable or herb gardens, it acts as a magnet for bees and other pollinators while adding a charming, cottage-style appeal with its petite blue buds.

Native to the Mediterranean, borage is a somewhat gangly plant, but you barely notice it because the star-shaped flowers are so vibrant. It also boasts a greenish-grey stem and leaves that are covered in a prickly fuzz which acts as a deterrent for insects.

After planting your borage in early spring, its blooms will emerge in June and July, hanging in downward facing clusters. Both the flowers and the leaves of the plant are edible, with a unique flavor similar to a cucumber. Use the leaves while they are young because as the plant matures, the stalks and leaves become covered with a prickly fuzz.

Botanical Name Borago officinalis
Common Name Borage, bee bush, star flower
Plant Type Annual herb
Size 1–3 ft. tall, 6–18 in. wide
Sun Exposure Full sun to part shade
Soil Type Dry, moist but well-drained
Soil pH 4.5–8.5 (acidic to alkaline)
Bloom Time Summer
Flower Color Blue
Hardiness Zones 2–11 (USDA)
Native Area  Europe
borage in the garden

The Spruce / Autumn Wood

borage in a landscape

The Spruce / Autumn Wood

Harvesting edible flowers of borage
Joshua McCullough / Getty Images
Honey Bee on borage flower
Caroline Brinkmann / Getty Images

How to Plant Borage

Caring for borage is rather simple, as the herb doesn't require any special treatment. Its ability to thrive in even the driest soils or drought-like weather has earned it an easy-to-care-for reputation. This fast-growing plant is normally planted from seeds; potted nursery starts are not commonly available.

Although accepting of just about any soil, borage does best in rich, moisture-retentive soil, so you may want to blend in compost to a depth of about 12 inches before planting. Plant the seeds 1/4 to 1/2 inch deep in early spring after the final frost has passed. Thin them when they are 6 to 8 inches tall to a spacing of 18 to 24 inches apart.

Borage can bloom from late spring through summer and will reach maturity in about eight weeks, at which point you can harvest the leaves and flowers as need. Keep in mind, the plants will start to decline if they are not deadheaded and are left to go to seed. Staggering your planting times will give you a longer period of bloom and provide a longer harvest time. If the flowers fade before you have a chance to deadhead them, the plants will re-seed on their own.

If you choose to start seed indoors three to four weeks before the last frost, make sure to transplant them into the garden before they become pot-bound, but not until the soil has warmed and the plants have been hardened off.

There are few pest or disease problems with borage, though powdery mildew may sometimes appear.

Borage Care

Light

Borage will grow in full sun to part shade. However, growing borage plants in full sun will give you the best chance at a plant with lots of blooms and stocky stems.

Soil

The good news: Borage can thrive in even the most dismal of soils, so there's no need to carve out a special spot in your garden for this herb. However, given the choice, the plan prefers moist but well-drained soil with a pH level between 6.0 and 7.0. Amending your soil with organic matter will also help give your plants a nutritional boost.

Water

As your borage is growing from seed and getting established in your garden, water it regularly, at least every few days. Once the plant is mature, you can cut back on your watering cadence, allowing the soil to dry out completely between waterings.

Temperature and Humidity

Borage is a particularly hardy herb, able to withstand temperatures on both ends of the spectrum. However, while it is tolerant of both heat and cool weather, it will not be able to withstand a hard frost, so care should be taken to harvest all you need from the plant before then. It has no special humidity needs.

Fertilizer

Borage plants in poor soil will benefit from periodic feeding with any fertilizer labeled for use on edible plants. Something with a high phosphorous number (the middle number on a fertilizer package) will help keep them in flower.

Borage Varieties

Most gardeners plant the pure species plant, Borago officinalis. However, there are two common cultivars, as well as a closely related species:

  • Borago officinalis ‘Variegata’ has white mottling on the green leaves. Flowers are less intense than common borage.
  • Borago officinalis ‘Alba’, also called white borage, blooms later in the season than blue varieties, with lovely white flowers. "Alba" is a sturdier plant than common borage.
  • Creeping borage (Borago pygmaea) is a sprawling species with pale blue flowers that bloom from late spring to late fall. Creeping borage is a short-lived perennial species.

Pruning

The plants will bloom for many weeks if the older flowers are trimmed off (deadheaded). If you prune back borage by one-half in midsummer, it will prompt new tender leaves for late summer harvest.

Harvesting Borage

Borage adds a bit of flavor and a great deal of color to salads, soups, dips & spreads, open-face sandwiches, beverages, and ice cubes. As with all edible flowers, use borage sparingly until you know how it affects you, especially if you have plant allergies.

Chop the leaves finely for use in cooking. The young stalks are also edible; prepare them as you would celery or similar vegetables. The cucumber-like taste of borage makes the leaves and stalks useful in salads or in soups or stews. The colorful flowers will add color to summer salads.

How to Grow Borage in Pots

Borage will grow well in a pot at least 12 inches deep filled with standard potting mix. It will likely need watering every week when grown in pots, but take care not to overwater.

Propagating Borage

Borage plants produce lots of black seeds, which can be collected to plant elsewhere the following spring. Volunteers that sprout up from self-seeding can easily be transplanted elsewhere in the garden.

Overwintering

Borage self-seeds very freely, so if you don't want lots of volunteer plants, it's best to pull the plants from the ground at the end of the season. Borage rots easily, so it makes a great addition to compost heaps.