Herb · Boraginaceae
Borage
Borago officinalis
Sow it just once and the blue star flowers and bees return on their own.
Full sun
Every 3–7 days
50–86°F · 10–30°C
55–75 days
Overview
Borage is the easygoing herb topped with bright blue, star-shaped flowers that bees simply can't resist. This fast-growing annual from the borage family thrives in full sun and shrugs off poor, dry ground that would stall pickier plants. Sow it once and it tends to dig in for the long haul.
Young leaves and open flowers deliver a clean, cucumber-like taste that brightens summer drinks, salads, and candied garnishes. Stiff bristly hairs cover the whole plant, so gloves more than earn their keep at harvest. Pick both leaves and flowers while they're young and tender for the best of them.
The ease borage offers comes with a habit of spreading. Leave it to flower and shed seed and it reseeds itself freely, popping up across the garden the next year, so a quick round of deadheading keeps it right where you planned.
Care
The short version: give it full sun and well-drained soil, even on the lean and dry side. Water to settle it in, then ease off once it's established, skip the heavy feeding, and deadhead the flowers to slow its eager self-seeding.
Light
Borage craves full sun to grow stocky and bloom hard, though it gets by in partial shade. Short it on light and you'll get a tall, floppy plant that leans and topples.
Water
Water often enough to hold the soil evenly moist while the plant digs in. From there it grows fairly drought-tolerant and handles lean, dry ground, so ease off and simply steer clear of waterlogging.
Soil
Plain well-drained garden soil suits it just fine, and it even tackles the poor, dry spots that defeat other herbs. A pH of 6.0 to 7.0 is the sweet spot, but borage stays unfussy about most things beyond drainage.
Temperature
It grows across a generous band, from roughly 50°F to 86°F (10°C to 30°C). Frost finishes an annual borage, so let the cold pass before you sow.
Humidity
Everyday outdoor air around 40% to 60% is all it wants. Good airflow matters far more than any humidity number, since crowded, stagnant air invites powdery mildew onto the leaves.
Feeding
Borage ranks as a light feeder that asks for almost nothing. A handful of compost or a balanced fertilizer at planting carries it on poor soils, while rich ground only pushes weak, floppy stems.
Pruning
Pinch the growing tips early for a bushier, sturdier plant, and deadhead spent flowers to keep the blooms rolling and rein in the heavy self-seeding. Trim back any leggy or flopping growth to freshen the foliage.
Repotting
Borage isn't truly a container plant. Its taproot resents being moved, so it gets direct-sown where it grows rather than potted up or repotted.
Size & spacing
Plants climb to 18 to 35 inches (45 to 90 cm) tall and fan out 12 to 24 inches (30 to 60 cm) wide. Hand each one that much room so air flows through and mildew keeps its distance.
When to plant
Borage thrives on warmth and balks at being moved, so kick off the season once frost clears out. Drop the seed straight into warm spring soil, watch the blue flowers unfurl from early summer, and pick young leaves and blooms all the way through to fall.
Northern hemisphere
Southern hemisphere
Typical months for a temperate climate: start earlier in warm zones, later where spring frosts linger.
- Sow: Generally not recommended; borage has a taproot and resents transplanting. If started indoors, sow in deep pots 3-4 weeks before last frost.
- Plant: Direct-sow after the last spring frost once soil has warmed
- Harvest: Blue star-shaped flowers appear from early summer through fall; harvest young, tender leaves and open flowers as needed
Hardiness
USDA hardiness zones: 2–11
Temperature: down to -46°C
Troubleshooting
Borage brushes off most trouble, and the handful of issues it does run into stay mild and easy to read. Keep an eye on the fresh growth and the crowded lower leaves for the earliest signs. Match what you spot below and jump in early.
Volunteer seedlings springing up across the beds
Borage scatters seed with abandon as a self-seeder, so one plant left to flower and drop its seed returns as a throng of volunteers the following year. Clip the spent flowers before the seed ripens, then hoe or tug the young seedlings while they lift out easily. Cut plants back ahead of seed drop and the spread stays well in hand.
Fix:
- Deadhead spent flowers before seed sets to limit reseeding
- Pull or hoe unwanted volunteer seedlings while young
- Harvest or cut plants before mature seed drops
Tiny soft bodies massing on fresh shoots and leaf backs
Spot soft-bodied clusters crowding the tender tips and undersides of leaves, plus a sticky honeydew film, and you've found aphids. Blast them off with a sharp jet of water and most scatter, while borage pulls in ladybugs and lacewings that polish off the rest, so a small colony seldom earns a second thought. Save insecticidal soap for the rare time numbers run away from you.
Fix:
- Spray plants with a strong jet of water to dislodge aphids
- Tolerate minor populations, as borage attracts beneficial predators such as ladybugs and lacewings
- Use insecticidal soap only if infestation is severe
Chalky white film creeping over the leaf tops
A dusty white bloom on the upper leaves means powdery mildew, a fungus that grabs hold across warm days and cool, humid nights, especially when plants jostle for room. Open up the planting so air sweeps through, snip off the worst leaves, and keep the foliage dry. Expect it mostly late in the season, and know it seldom finishes a plant off.
Fix:
- Improve air circulation by thinning crowded plants
- Remove and discard heavily affected foliage
- Avoid overhead watering
Tall, top-heavy stems tipping after a storm or gust
Fast and hollow by nature, borage turns leggy and brittle and buckles under its own weight when rich soil or shade pushes it too quickly. Pinch the tips early to coax a stockier, well-branched plant, then hand it light staking or sturdy neighbors to lean against. Plant it in full sun on lean ground and the growth stays tight enough to hold itself upright.
Fix:
- Pinch tips early to promote bushier, sturdier growth
- Provide light staking or grow among supporting companion plants
- Site in full sun and avoid over-fertilizing
Toxicity
Borage holds an unusual spot: people happily eat its flowers and young leaves, yet the plant carries pyrrolizidine alkaloids that can injure the liver in quantity. Enjoy it sparingly as a garnish, and keep horses, livestock, rabbits, and birds away from it completely, since these animals face far greater risk than a person taking the odd taste.
Toxic to
Cats · Dogs · Horses · Rabbits · Livestock · Birds
Safe for
People
Cats Mild
One or two nibbles rarely brings on worse than a mild stomach upset, yet the pyrrolizidine alkaloids in the leaves stack up in the liver over time. Stop a cat from grazing the plant again and again.
Dogs Mild
A curious dog chewing a leaf might end up with a queasy stomach and not much else, but regular helpings build a genuine liver worry as the alkaloids gather. Guide dogs clear of the foliage.
Horses Toxic
Pyrrolizidine alkaloids hit horses especially hard, scarring the liver as they accumulate. The harm builds quietly, so weight loss, a dull coat, and odd behavior can surface well after grazing. Keep borage out of pasture and hay.
Rabbits Toxic
Bristly and alkaloid-laden, these leaves are no treat for a rabbit, and the toxin burdens the liver with each feeding. Never offer borage as forage.
Livestock Toxic
Cattle, sheep, and goats that browse borage swallow pyrrolizidine alkaloids that quietly wear down the liver over weeks and months. Listlessness, weight loss, and poor thrift flag the slow harm. Keep it well away from grazing ground.
Birds Toxic
Those same liver-toxic alkaloids make borage foliage a bad bet for poultry and pet birds, so keep it off the menu.
People Edible in moderation
Young leaves and blue flowers are a familiar kitchen herb, fine to eat now and then for their cool, cucumber taste. The catch sits in the pyrrolizidine alkaloids, which can strain the liver under large or steady use, so lean on borage as a garnish rather than a daily green.
Wear gloves or long sleeves when handling or harvesting, as the stiff bristly hairs can mildly irritate skin. Consume flowers and young leaves only in moderation due to pyrrolizidine alkaloid content.
Helpline numbers
United States
ASPCA Animal Poison Control: (888) 426-4435 (fee applies)
United Kingdom
Animal PoisonLine: 01202 509000 (fee applies)
Australia
Animal Poisons Helpline: 1300 869 738
Varieties
Borage shows up in just a couple of forms, split mainly by flower color. Both grow and taste alike.
Borago officinalis (common borage)
Picture borage and this standard species is what comes to mind: bright blue, star-shaped flowers above bristly, cucumber-flavored leaves.
Borago officinalis 'Alba' (white borage)
Swap the blue blooms for crisp white ones and you have this selection, identical to the species in every other respect.
Companions
Borage earns its place beside fruiting crops by pulling in bees and other pollinators that lift their yields.
Plant near
Tomato: Borage attracts pollinators and beneficial insects and is a traditional companion planted near tomatoes
Strawberry: Borage is a classic companion for strawberries, drawing pollinators that improve fruit set
Squash: Its abundant blue flowers attract bees and other pollinators that benefit pollination of squash and other cucurbits
How to propagate
Borage practically plants itself, which leaves seed as the only method that counts and the only one you'll ever reach for.
SeedEasy
Direct-sow outdoors after the last spring frost once the soil has warmed · Seeds typically germinate in 1-2 weeks and plants establish within several weeks
Drop borage seed right into the spot where you want it growing, because its deep taproot hates being shifted. Hold off until the last spring frost passes and the soil warms, and the seeds break ground in 1 to 2 weeks before bulking up over the next few weeks. Once it takes hold, it reseeds itself for years on end.
Myths
Borage is a completely safe culinary herb you can eat in any amount.
Its leaves and stems hold pyrrolizidine alkaloids that can injure the liver under large amounts or a long run of eating. Flowers and young leaves work fine as the odd garnish, so treat borage as a flavoring, not a staple green.
Planting borage once is enough because it's only an annual.
True, it dies back each year, yet it sheds so much seed that it comes back on its own season after season. Let it set seed and one plant can colonize a whole bed and turn weedy.