Herb · Boraginaceae
Borage
Borago officinalis
Plant it a single spring and the bristly stems and starry blue blooms return by themselves, humming with bees.
Full sun
Every 3–7 days
50–86°F · 10–30°C
55–75 days
Overview
Borage is the easygoing herb crowned with bright blue, five-petaled stars that bees swarm without pause. A fast annual in the borage family, it sits happiest in full sun and shrugs off the poor, dry ground that would stall a fussier plant. Tuck the seed in once and it tends to root in for the long haul.
Pinch a young leaf or an open flower and you taste a clean, cool cucumber flavor that finds its way into summer drinks, salads, and candied garnishes. Every stem, leaf, and bud bristles with stiff hairs, rough enough under the fingers that gloves earn their keep at harvest. Pick both leaves and flowers while they are young and tender.
What borage hands you in ease it claws back in spread. Allowed to bloom out and shed, it reseeds itself freely and breaks ground all across the bed the next year, so a little deadheading keeps it standing where you put it.
Care
The short version: give it full sun and well-drained ground, even on the lean, dry side. Water to settle the roots, then ease off once it stands on its own, hold back on heavy feeding, and snip the flowers to slow its eager self-seeding.
Light
Borage craves full sun to grow thick and bloom hard, though it gets by in partial shade. Starve it of light and you get a tall, soft plant that leans and topples.
Water
Keep the soil evenly moist with regular watering while the roots take hold. Once settled, it turns fairly drought-tolerant and copes with lean, dry ground, so ease off and just keep it from sitting waterlogged.
Soil
Plain well-drained garden soil suits it, and it even works the poor, dry spots that defeat other herbs. A pH of 6.0 to 7.0 is the sweet spot, though borage cares little about much past good drainage.
Temperature
It grows across a broad span, from roughly 50°F to 86°F (10°C to 30°C). Frost ends an annual borage outright, so let the cold pass before you sow.
Humidity
Ordinary outdoor air around 40% to 60% is all it wants. Moving air matters more than any humidity figure, since still, crowded conditions invite powdery mildew across the leaves.
Feeding
Borage is a light feeder that asks for almost nothing. A little compost or a balanced fertilizer at planting carries it on poor soils, and rich ground only throws up weak, floppy stems.
Pruning
Pinch the growing tips early for a fuller, stiffer plant, and deadhead spent flowers to keep fresh blooms coming and to curb the heavy self-seeding. Cut back any leggy or sprawling growth to refresh the foliage.
Repotting
Borage is no container plant. Its taproot resents being moved, so sow it straight where it grows instead of potting it up or shifting it later.
Size & spacing
Plants stand 18 to 35 inches (45 to 90 cm) tall and spread 12 to 24 inches (30 to 60 cm) wide. Allow each one that much room so air can pass through and mildew stays off.
When to plant
Borage runs on warmth and hates being shifted, so the season opens when the frost lifts. Press the seed straight into warm spring soil, watch the blue stars unfurl from early summer, and pick young leaves and blooms right 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 few things that do reach it stay mild and easy to spot. Check the soft new growth and the crowded lower leaves for the earliest signs. Match what you find below and act early.
Self-sown seedlings carpeting the beds the following season
Borage scatters seed like few other herbs, so a single plant allowed to bloom out and shed turns into a thicket of volunteers the following year. Snip the faded flowers off before the seed ripens and firms, and lift or hoe the small seedlings while their roots are still shallow and loose. Cutting plants down before the seed falls keeps the spread reined in.
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 plump insects massed along tender tips and beneath the leaves
Look closely at the soft tips and the backs of the leaves and you'll find tiny pear-shaped aphids packed together, their feeding leaving a tacky honeydew sheen on the foliage. A sharp blast of water sweeps most of them off the stems, and the ladybugs and lacewings that borage pulls in pick off the rest, so a small cluster seldom calls for action. Save insecticidal soap for the rare colony that runs wild.
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
Pale floury film settling over the tops of the leaves
A pale, floury dust settling over the top of the leaves is powdery mildew, a fungus that grabs hold on warm afternoons and damp, cool nights, worst where plants press up against each other. Pull a few plants to open gaps so air slips through, snip away the most coated leaves, and keep the spray off the foliage. It tends to surface late in the season and almost never finishes the plant off.
Fix:
- Improve air circulation by thinning crowded plants
- Remove and discard heavily affected foliage
- Avoid overhead watering
Tall hollow stems buckling and sprawling once wind or rain hits
The stems of borage are fast-grown and hollow, so a plant pushed by rich soil or shade stretches leggy and brittle and buckles under its own crown of leaves and flowers. Pinch the tips while young and the plant branches into something stockier and thicker through the base. A light stake or a few sturdy neighbors give it something to lean on, and full sun on lean ground keeps the growth tight enough to stand alone.
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 odd place: people eat its flowers and young leaves, yet the plant carries pyrrolizidine alkaloids that can wear on the liver in quantity. Enjoy it sparingly as a garnish, and keep horses, livestock, rabbits, and birds off it completely, since these animals face far more harm than a person taking the occasional taste.
Toxic to
Cats · Dogs · Horses · Rabbits · Livestock · Birds
Safe for
People
Cats Mild
One or two nibbles seldom amounts to more than a mild stomach upset, yet the pyrrolizidine alkaloids in the bristly leaves settle in the liver over time. Stop a cat from coming back to graze the plant again and again.
Dogs Mild
A dog that bites off a leaf out of curiosity may end up briefly queasy and nothing worse, but repeat helpings build a genuine liver risk as the alkaloids stack up. Steer dogs clear of the foliage.
Horses Toxic
Horses are hit hardest by pyrrolizidine alkaloids, which scar the liver as the dose accumulates. The harm sets in quietly, so weight loss, a dull coat, and odd behavior may show up long after the grazing happened. Keep borage out of pasture and out of hay.
Rabbits Toxic
The stiff, bristly, alkaloid-loaded leaves are no treat for a rabbit, and the toxin burdens the liver with each mouthful. Never offer borage as forage.
Livestock Toxic
Cattle, sheep, and goats that browse borage swallow pyrrolizidine alkaloids that wear on the liver across weeks and months. Sluggishness, weight loss, and poor condition signal the slow damage. 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 feed entirely.
People Edible in moderation
The tender young leaves and the blue star flowers are a long-loved kitchen herb, fine to eat here and there for their cool, cucumber flavor. The snag is the pyrrolizidine alkaloids, which can tax the liver with heavy or steady use, so use borage to garnish a dish rather than as an everyday 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, set apart almost entirely by flower color. Both grow and taste the same.
Borago officinalis (common borage)
The plain species is the one most gardeners picture: bright blue, star-shaped flowers above leaves coated in stiff bristles and tasting of cool cucumber.
Borago officinalis 'Alba' (white borage)
This form swaps the blue stars for clean white ones, while everything else about the plant stays identical.
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 sows itself, which leaves seed as the only method that counts and the only one you will 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
Press borage seed right into the bed where you intend it to grow, because the long taproot hates being lifted and moved. Hold off until the last spring frost has passed and the soil has warmed, then the seedlings break ground in 1 to 2 weeks and bulk up across the next several weeks. Once it has rooted in, it reseeds itself for years on end.
Myths
Every part of borage counts as harmless kitchen fare, safe to enjoy in unlimited quantity.
The bristly leaves and hollow stems hold pyrrolizidine alkaloids that can wear on the liver when eaten in quantity or over a long run. The flowers and tender young leaves do fine as an occasional garnish, but treat borage as a flavoring, not a staple green.
Because borage lives just one year, a single sowing is all the attention it will ever call for.
The plant does collapse and die back each year, but it sheds so much seed that it comes back on its own season after season. Leave it to ripen and drop seed and one plant can fill an entire bed and turn weedy.