Borage (Borago officinalis) is one of the friendliest plants you can put in a garden. It grows fast from seed, asks for very little, covers itself in star-shaped blue flowers, and keeps the bees busy from late spring to autumn. The young leaves taste faintly of cucumber, and the flowers make a pretty garnish.
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This guide walks through the whole growing process, from choosing a spot and sowing the seed to thinning, care, harvesting, saving seed, and dealing with the few problems borage gets. It's the main guide in my borage series, and it links to the more detailed posts on each topic.
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Borage at a Glance
- Type: Fast-growing annual herb, also called starflower
- Height: About 2 to 3 feet (60 to 90 cm)
- Sun: Full sun, tolerates light shade
- Soil: Well-drained, ordinary soil; no need to enrich it
- Sowing: Directly in the garden after the last frost
- Germination: About one to two weeks in warm soil
- Spacing: 12 to 18 inches (30 to 45 cm) between plants
- Flowers: Blue (or white in the 'Bianca' type) from late spring through summer
- Self-seeds: Yes, readily
Why Grow Borage?
Borage earns its space in the garden in several ways:
- It's a bee magnet. The flowers are a reliable nectar source for honeybees, bumblebees, and other pollinators, which also helps nearby vegetables and fruit set well.
- It's easy. It grows in ordinary soil, copes with short dry spells once established, and rarely needs fertilizer.
- It's edible. The flowers are a traditional garnish for salads and drinks, and young leaves have a mild cucumber flavor. Before you eat the leaves, read the safety note near the end of this guide.
- It comes back by itself. Borage self-seeds, so one planting can give you new plants year after year.
Where to Plant Borage
Choose a spot with full sun, meaning at least six hours of direct light. Borage tolerates light shade, but plants grown in shade get leggy and flower less. Because the plant gets big and spreads its leaves wide, give it room away from small, delicate neighbors.
The soil can be ordinary garden soil, as long as it drains well. Borage doesn't want rich soil: too much fertilizer or compost produces big leaves at the expense of flowers. Loosen the soil to about 8 inches (20 cm) and remove weeds before sowing, because borage has a long taproot that appreciates a loose bed.
When to Plant Borage
Borage is an annual that likes warm weather, so sow it after your last frost, once the soil has warmed. Seeds germinate best in warm soil, roughly 60 to 77°F (15 to 25°C). Established seedlings may shrug off a light frost, but a hard freeze can kill young plants, so don't rush.
If your spring is short or cold, you can start seeds indoors three to four weeks before the last frost. My guide on how to start borage indoors explains how, and my guide to transplanting borage seedlings shows how to move them without harming the taproot. For most gardeners, sowing directly into the garden is simpler and works just as well.
How to Sow Borage Seeds
- Prepare the bed. Loosen the soil, remove weeds, and rake the surface level.
- Sow the seeds about half an inch (1 cm) deep, dropping one every few inches, and cover them lightly with soil.
- Water gently, using a fine spray so you don't wash the seeds away.
- Keep the soil lightly moist until seedlings appear, usually within one to two weeks.
- Thin the seedlings as described below, so the strongest plants have room to grow.
Fresh seed from a reliable seller sprouts best, and it's worth checking the packing date. For tips on choosing seed, comparing blue and white varieties, and storing it, see my guide to borage seeds.
Thinning Borage Seedlings
Borage seeds usually sprout well, so the seedlings come up crowded. When they are about 2 inches (5 cm) tall, thin them so that there is one plant every 12 to 18 inches (30 to 45 cm). It feels harsh, but a mature borage plant is large, and crowded plants compete for water, sun, and nutrients and are more prone to mildew.
Snip the weaker seedlings off at soil level with scissors instead of pulling them. Pulling disturbs the roots of the neighbor you want to keep, and borage dislikes root disturbance.
After thinning, spread a light layer of mulch around the plants. It holds moisture in the soil and keeps young plants from wilting in warm spells. Borage seedlings need very little else.
Borage Plant Care
Borage really is low maintenance. Here's what it needs:
Watering
Water young plants regularly until they are established, giving them a good soak instead of a light sprinkle. Once mature, borage tolerates short dry spells, but it flowers best with steady moisture. Water at the base of the plant, in the morning, so the leaves dry quickly.
Feeding
Borage rarely needs fertilizer. Rich soil or heavy feeding makes lush leaves and fewer flowers, so skip it unless growth looks pale and slow.
Pinching and pruning
Pinch out the tips of young plants if you want them bushier and shorter, since pinching encourages side branches. A pinched plant has more stems and, in turn, more flowers.
Supporting tall plants
Borage stems are hollow and brittle, and tall plants can flop or snap in strong wind or heavy rain. A stake or a sheltered spot helps, and so does pinching early.
Deadheading and succession sowing
Borage blooms for many weeks, and removing faded flowers keeps it flowering longer. If you want fresh leaves and blooms all season, sow a few more seeds every four weeks through early summer. This staggered sowing is also recommended by the University of Illinois Extension.
Growing Borage in Containers
Borage can grow in pots, but it needs a deep container, at least 12 to 16 inches (30 to 40 cm), because of its taproot. Use a good potting mix, make sure there are drainage holes, and keep one or two plants per large pot. The compact white 'Bianca' type is a good fit for pots. Water whenever the top inch of soil is dry. For more detail, see my guide to growing borage in containers.
Harvesting Borage
You can start picking once the plant is growing strongly and flowering. The stems and leaves are covered in coarse, silvery hairs that get prickly as the plant matures, and they can irritate the skin of some people, so wear gloves when you handle it.
Harvesting the leaves
Pick the youngest leaves, which are softer and less hairy. Snip them off with clean scissors or snips, and never strip more than about a third of the plant at one time.
Harvesting the flowers
Snip each flower stalk just below a cluster of blossoms, and pick them fresh, since they wilt quickly. Regular picking encourages more blooms. For ideas and tips, see my guide to harvesting borage flowers.
A well-grown plant keeps producing side shoots with more buds and flowers, and the more you harvest and deadhead, the longer the plant keeps blooming.
How to Collect and Store Borage Seeds
Borage seeds drop soon after they ripen, so timing matters. To collect them:
- Let some flowers fade and form seed heads instead of picking everything.
- Watch the seed heads. When they dry out and turn brown, and the seeds are dark and hard, they are ripe.
- Collect them quickly. Gardeners often slip a small paper bag loosely over a ripe seed head, or hold a tray underneath, so the seeds fall into it.
- Spread the seeds out in a dry place for a week or two to finish drying.
- Store them in a labeled paper envelope in a cool, dry, dark place.
Stored this way, the seeds stay usable for a few years. If you'd rather not have borage everywhere next year, pick the flowers before the seeds ripen. If you grow blue and white types together, saved seed may produce plants of both colors.
Companion Planting with Borage
Borage is a classic companion plant because it draws pollinators and beneficial insects into the garden. It's often grown near tomatoes, squash, cucumbers, zucchini, and strawberries, all of which need pollination or benefit from a lively garden. For an example of borage in a vegetable bed, see my guide to growing Black Zebra tomatoes.
You'll often read that borage repels tomato hornworms and cabbage worms, or that it improves the flavor of strawberries and squash. Many gardeners report this, but scientific evidence for those specific effects is limited, so treat them as folklore. The solid benefit is pollinators.
Borage Pests and Diseases
Borage is generally healthy, but a few problems can appear:
Powdery mildew
This is the most common problem. It shows up as white, powdery patches on the leaves, especially in warm, humid weather. To prevent it, thin plants so air can move between them, water at the base in the morning, and remove badly affected leaves. Full sun also helps.
Aphids and slugs
Occasionally, aphids gather on soft growth, and slugs or snails nibble young seedlings. A strong jet of water usually deals with aphids, and protecting seedlings (or sowing a little extra) helps with slugs.
Plants that flop
Tall, brittle plants flop in wind and rain. Stake them, pinch young plants to keep them compact, and avoid overfeeding.
What to Do at the End of the Season
Borage grows quickly, blooms for months, and eventually flops and fades. It's easy to pull. Healthy plants can go straight on the compost pile, or you can lay them on a garden path to break down slowly and add organic matter to the soil. Compost only healthy, disease-free plants, and remove seed heads first if you don't want volunteers.
A Note About Eating Borage
The flowers are the traditional garnish, and young leaves have been eaten in small amounts. However, borage naturally contains pyrrolizidine alkaloids (PAs), which can harm the liver in large amounts or with long-term use. Avoid eating large quantities regularly. Pregnant or breastfeeding people, people with liver disease, and young children should avoid borage unless a healthcare professional says otherwise. My complete guide to borage leaves covers the details.
Growing Borage FAQs
Is borage easy to grow?
Yes. It's one of the easiest herbs to grow from seed, needing only sun, ordinary soil, and a little water.
When should I plant borage?
Sow it outdoors after the last frost, once the soil is warm. You can sow again every four weeks through early summer for continuous leaves and flowers.
How long does borage take to sprout?
Usually one to two weeks in warm soil. It can take longer if the soil is cool.
How far apart should I space borage plants?
Thin seedlings to 12 to 18 inches (30 to 45 cm) apart, because the plants grow large.
Does borage need full sun?
It prefers full sun but tolerates light shade. Shaded plants tend to be leggy and flower less.
Does borage come back every year?
Borage is an annual, but it self-seeds readily, so new plants usually appear where the old ones dropped seed.
How do I stop borage from self-seeding?
Pick or deadhead the flowers before the seeds ripen, and pull up unwanted seedlings while they're small.
Can I grow borage in a pot?
Yes, in a deep container with drainage holes, at least 12 to 16 inches (30 to 40 cm) deep. The compact white type suits pots well.
When do I harvest borage?
Pick young leaves any time the plant is growing strongly, and harvest flowers as they open. Regular picking encourages more blooms.
Are borage leaves and flowers safe to eat?
The flowers are a traditional garnish, and young leaves have been eaten in small amounts. Because borage contains pyrrolizidine alkaloids, avoid eating large amounts regularly, and read the safety note above.
Gardening Supplies I Recommend
Explore these useful supplies for growing and caring for borage.
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A large bag of the classic blue-flowered borage, enough for several sowings through early summer or to share with friends.
A white-flowered borage, handy if you want a softer color or a compact plant for pots. Look for 'Bianca' on the listing.
Clean, sharp snips make quick work of harvesting young leaves and flowers, thinning seedlings, and deadheading.
Borage stems and mature leaves are covered in coarse hairs that some people find scratchy, so gloves make harvesting more comfortable.
Final Thoughts
Borage rewards a little effort with a lot of flowers. Sow it in full sun after the last frost, thin it so it has room, harvest often, and let a few flowers go to seed. After that, the plant largely looks after itself, and the bees will thank you all summer.
Watch: The Benefits of Borage
More Borage Guides
- The Complete Guide to Borage Leaves
- Borage Seeds
- How to Start Borage Indoors
- How to Transplant Borage Seedlings
- How to Grow Borage in Containers
- Harvesting Borage Flowers
- Amazing Benefits of Borage Plant
Have a question or a tip about growing borage? Leave it in the comments below. If you found this guide helpful, feel free to share it with a gardening friend.
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