Herb · Boraginaceae
Borage
Borago officinalis
Plant it just once, and the blue star flowers and bees happily return on their own.
Full sun
Every 3–7 days
50–86°F · 10–30°C
55–75 days
Overview
Borage is a wonderfully easygoing herb, the one with the bright blue, star-shaped flowers that bees simply adore. It's a fast-growing annual in the borage family, thriving in full sun and gentle about poor, dry ground that would frustrate fussier plants. Plant it a single time and it tends to make itself at home for the long haul, which makes it a lovely choice if you're just starting out.
The young leaves and the open flowers offer a clean, cucumber-like taste that's delightful in summer drinks, in salads, and as a candied garnish. The whole plant is covered in stiff bristly hairs, so a pair of gloves makes harvest comfortable and easy. You'll get the best of both leaves and flowers by picking them young and tender.
What borage offers in ease, it can give back a little too eagerly in spread. Left to flower and drop its seed, it reseeds itself freely and pops up around the garden the next year, but a touch of deadheading keeps it exactly where you want it, and that small habit is all it takes.
Care
The short version: give it full sun and well-drained soil, even ground that runs lean and dry. Water enough to settle it in, then relax and ease off once it's established, go light on the feeding, and snip the flowers to gently slow its eager self-seeding.
Light
Borage loves full sun, which helps it grow stocky and bloom generously, though it will happily make do with partial shade. Give it too little light and you'll end up with a tall, floppy plant that leans and tips over, so a bright spot really pays off.
Water
Keep the soil evenly moist by watering often enough while the plant is getting settled. After that it becomes fairly drought-tolerant and copes nicely with lean, dry ground, so you can ease right off and simply steer clear of waterlogging.
Soil
Ordinary well-drained garden soil is all it asks, and it even shrugs off poor, dry spots that defeat other herbs. A pH of 6.0 to 7.0 suits it best, but truly, borage isn't fussy about much beyond good drainage.
Temperature
It's comfortable across a generous range, from roughly 50°F to 86°F (10°C to 30°C). Frost will end an annual borage, so just give the cold time to pass before you sow and all will be well.
Humidity
Everyday outdoor air around 40% to 60% is plenty for it. Good airflow matters more than any humidity reading, since crowded, stagnant air is what tempts powdery mildew onto the leaves.
Feeding
Borage is a gentle light feeder that needs very little from you. A little compost or a balanced fertilizer at planting is enough on poor soils, and overly rich ground tends to grow weak, floppy stems, so less really is more here.
Pruning
Pinch the growing tips early for a bushier, sturdier plant, and deadhead spent flowers to keep fresh blooms coming and gently rein in the heavy self-seeding. Trim back any leggy or flopping growth to freshen up the foliage.
Repotting
Borage isn't really suited to pots. Its taproot resents being moved, so it's best direct-sown right where it'll grow rather than potted up or repotted later on.
Size & spacing
Plants reach 18 to 35 inches (45 to 90 cm) tall and spread 12 to 24 inches (30 to 60 cm) wide. Offer each one that much elbow room so air can move freely and mildew stays away.
When to plant
Borage thrives on warmth and would rather not be moved, so its season simply begins once frost is behind you. Pop the seed straight into warm spring soil, enjoy the blue flowers opening from early summer, and gather 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 takes most trouble in stride, and the few hiccups it does run into are mild and easy to spot. Keep a friendly eye on the fresh growth and the crowded lower leaves for early hints. Match what you notice below, step in gently, and you'll have it sorted in no time.
Baby seedlings turning up all over the beds next season
Borage is an enthusiastic self-seeder, so a single plant allowed to flower and scatter its seed often returns as a happy crowd of seedlings the following year. This is easy to stay on top of: snip the faded flowers before their seed ripens, and gently hoe or tug the young volunteers while they lift out with no effort. Trimming plants back before the seed falls keeps everything comfortably under control.
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
Little soft-bodied bugs gathering on tender new growth
If you spot tiny clusters on the fresh tips and the backs of the leaves, with a bit of sticky residue around them, those are aphids, and they are nothing to lose sleep over. A firm spray of water rinses most of them away, and because borage invites in ladybugs and lacewings, helpers usually arrive to handle the rest for you. Only reach for insecticidal soap if a colony truly gets ahead of 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
A pale dusty film creeping over the leaves
When you notice a chalky white dusting on the tops of the leaves, that is powdery mildew, a common fungus that settles in on warm days paired with cool, humid nights, and it loves plants packed tightly together. You can turn this around easily: open up the planting so air can move, pluck off the most affected leaves, and aim water at the soil rather than the foliage. It mostly shows up later in the season and very seldom does any lasting harm.
Fix:
- Improve air circulation by thinning crowded plants
- Remove and discard heavily affected foliage
- Avoid overhead watering
Tall plants tipping over once rain or wind arrives
Borage shoots up quickly with hollow stems, so a plant pushed along by rich soil or too much shade can grow leggy and brittle and lean over under its own weight. Happily, this is simple to prevent: pinch the tips early so the plant builds out stocky and well branched, and offer a little staking or some sturdy neighbors for it to rest against. Give it full sun and plain, lean ground, and it will stay compact enough to hold itself up.
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 sits in a curious place: people happily eat its flowers and young leaves, while the plant itself carries pyrrolizidine alkaloids that can harm the liver in larger amounts. Enjoy it in moderation as a garnish, and keep horses, livestock, rabbits, and birds away from it completely, since those animals face far more risk than a person enjoying the occasional taste.
Toxic to
Cats · Dogs · Horses · Rabbits · Livestock · Birds
Safe for
People
Cats Mild
If a cat takes a nibble or two, you'll usually see nothing worse than a mildly upset tummy, but the pyrrolizidine alkaloids in the leaves slowly collect in the liver. The kind thing to do is gently keep a cat from grazing the plant again and again.
Dogs Mild
A curious dog who tries a leaf might feel a touch queasy and little more, yet helping themselves on a regular basis brings a genuine liver worry as the alkaloids add up. Simply guide dogs away from the foliage.
Horses Toxic
Horses are particularly sensitive to pyrrolizidine alkaloids, which scar the liver as they gather. The harm builds quietly, so weight loss, a dull coat, and odd behavior may not appear until long after grazing. Please keep borage well out of pasture and hay.
Rabbits Toxic
The prickly, alkaloid-laden leaves are no kindness to a rabbit, since the toxin burdens the liver with each meal. It is best never to offer borage as forage.
Livestock Toxic
When cattle, sheep, and goats browse borage, they take in pyrrolizidine alkaloids that quietly wear on the liver across weeks and months. Listlessness, weight loss, and poor condition hint at that slow damage. Keep it well away from grazing ground.
Birds Toxic
Those same liver-toxic alkaloids make borage foliage a poor fit for poultry and pet birds, so it is wise to keep it off their menu.
People Edible in moderation
The young leaves and pretty blue flowers are a well-loved kitchen herb, perfectly fine to enjoy now and again for their cool, cucumber flavor. The one thing to keep in mind is the pyrrolizidine alkaloids, which can tax the liver with heavy or constant use, so think of borage as a lovely 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 comes in just a couple of forms, told apart mainly by their flower color. Both grow the same way and taste the same, so you really can't go wrong.
Borago officinalis (common borage)
This is the familiar species, the one most gardeners picture, with its cheerful blue, star-shaped flowers and bristly leaves that taste gently of cucumber.
Borago officinalis 'Alba' (white borage)
This pick swaps the blue blooms for soft white ones, and in every other respect it behaves just like the common form.
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 means seed is the one method that matters and the only one you'll ever need to learn.
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
Tuck borage seed right into the spot where you'd like it to live, because its deep taproot would rather not be disturbed by moving. Hold off until the last spring frost has passed and the soil feels warm, and you'll see sprouts in 1 to 2 weeks, with plants filling out over the next few weeks. Once it has found its footing, it will happily reseed itself for years to come.
Myths
Borage is a completely safe culinary herb you can eat in any amount.
Its leaves and stems hold pyrrolizidine alkaloids that can strain the liver if you eat a lot of them or keep it up over a long period. The flowers and young leaves are lovely as a once-in-a-while garnish, so simply treat borage as a flavoring, not a staple green.
Planting borage once is enough because it's only an annual.
It does fade away each year, but it scatters so much seed that it comes back on its own season after season. If you let it set seed freely, one plant can fill a whole bed and start to feel weedy.