Herb · Boraginaceae
Borage
Borago officinalis
Plant it just once and the blue star flowers and bees keep showing up on their own.
Full sun
Every 3–7 days
50–86°F · 10–30°C
55–75 days
Overview
Borage is that laid-back herb with the bright blue, star-shaped flowers that bees simply can't resist. It's a fast-growing annual in the borage family, loves full sun, and shrugs off the poor, dry ground that would stop fussier plants in their tracks. Plant it once and it usually settles in for the long run.
The young leaves and the open flowers have a clean, cucumber-like taste that's lovely in summer drinks, salads, and as a candied garnish. The catch? The whole plant is covered in stiff bristly hairs, so gloves are well worth it at harvest. Either way, pick both the leaves and flowers while they're young and tender.
What borage hands you in easygoing growth, it can take back in spread. Let it flower and drop seed and it'll reseed itself with ease, popping up across the garden the next year, so a bit of deadheading keeps it right where you want it.
Care
The short version: give it full sun and well-drained soil, even if that ground is on the lean and dry side. Water it in to get it going, then ease right off once it's settled, skip the heavy feeding, and deadhead the flowers to slow down all that eager self-seeding.
Light
Borage really wants full sun so it grows stocky and flowers like mad, though it'll get by in partial shade. Give it too little light and you'll end up with a tall, floppy plant that leans over and falls.
Water
Water it often enough to keep the soil evenly moist while it's getting established. Once it's settled it becomes fairly drought-tolerant and handles lean, dry ground just fine, so ease off and simply steer clear of waterlogging.
Soil
Ordinary well-drained garden soil does the trick, and it'll even cope with poor, dry spots that leave other herbs struggling. A pH of 6.0 to 7.0 is the sweet spot, but borage isn't really fussy about anything past good drainage.
Temperature
It happily grows across a wide range, roughly 50°F to 86°F (10°C to 30°C). Frost finishes off an annual borage, so just wait for the cold to clear before you sow.
Humidity
Plain old outdoor air around 40% to 60% is all it needs. Honestly, good airflow matters more than any humidity number, since crowded, stagnant air is what brings powdery mildew to the leaves.
Feeding
Borage is a light feeder that asks for next to nothing. A little compost or a balanced fertilizer at planting time has it covered on poor soils, and rich ground only gives you weak, floppy stems.
Pruning
Pinch the growing tips early for a bushier, sturdier plant, and deadhead spent flowers to keep the blooms coming while reining in all that self-seeding. Trim back any leggy or flopping growth to freshen up the foliage.
Repotting
Borage isn't really cut out for pots. Its taproot hates being moved, so it's sown straight where it'll grow instead of being potted up or repotted.
Size & spacing
Plants get to about 18 to 35 inches (45 to 90 cm) tall and spread 12 to 24 inches (30 to 60 cm) wide. Give each one that much elbow room so air can move through and mildew stays away.
When to plant
Borage loves warmth and hates being moved, so its season kicks off the moment frost is done. Drop the seed straight into warm spring soil, enjoy the blue flowers opening from early summer, and keep picking young leaves and blooms all the way 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 problems, and the handful it does run into are mild and pretty easy to spot. Keep an eye on the fresh growth and the crowded lower leaves for the earliest signs. Find what matches below and jump in early.
Surprise seedlings sprouting all over the garden
Borage is a serious self-seeder, so one plant left to bloom and scatter seed turns into a whole crowd of volunteers the next spring. Snip off the spent flowers before the seed ripens, and pull or hoe the little seedlings while they still lift out easily. Cutting the plants back before the seed falls is the simplest way to keep the spread 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 piling up on fresh growth and the backs of leaves
See those clusters? They're aphids, and they like to crowd the soft new tips and hide under the leaves, dropping sticky honeydew as they go. A firm blast of water shakes most of them loose, and borage happens to bring in ladybugs and lacewings that mop up the rest, so a small batch isn't really a big deal. Save the insecticidal soap for when things actually get out of control.
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
Powdery white film creeping over the leaves
That chalky white dust on the top of the leaves is powdery mildew, a fungus that likes warm days paired with cool, humid nights, and it really thrives where plants sit too close together. Open things up so the air can flow, pull off the worst of the leaves, and try to keep water off the foliage. It mostly shows up late in the season and won't usually take the plant down.
Fix:
- Improve air circulation by thinning crowded plants
- Remove and discard heavily affected foliage
- Avoid overhead watering
Top-heavy plants tipping over once the rain or wind hits
Borage shoots up fast and hollow, so a plant pushed along by rich soil or shade goes leggy and brittle and ends up collapsing under its own weight. Pinch those tips early and you'll get a shorter, branchier plant, and a little staking or some sturdy neighbors give it something to lean on. Pop it in full sun on lean ground and the growth stays 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 lands in a curious spot: folks happily eat its flowers and young leaves, yet the plant carries pyrrolizidine alkaloids that can hurt the liver in larger amounts. Enjoy it in moderation as a garnish, and keep horses, livestock, rabbits, and birds away from it completely, because they're at far greater risk than a person grabbing the odd taste.
Toxic to
Cats · Dogs · Horses · Rabbits · Livestock · Birds
Safe for
People
Cats Mild
One or two nibbles usually means nothing worse than a mild upset stomach, but the pyrrolizidine alkaloids in the leaves slowly stack up in the liver. So it's best to stop a cat from snacking on it again and again.
Dogs Mild
A nosy dog that chews on a leaf might get a bit queasy and not much else, though regular servings turn into a real liver worry as the alkaloids build up. Keep dogs clear of the foliage.
Horses Toxic
Horses take pyrrolizidine alkaloids especially hard, since the toxin scars the liver as it accumulates. It works in quietly, so weight loss, a dull coat, and odd behavior may not show up until well after the grazing. Keep borage out of pasture and hay.
Rabbits Toxic
Those prickly, alkaloid-packed leaves are no snack for a rabbit, and the toxin hits the liver with every single feeding. Just don't put borage out as forage.
Livestock Toxic
Cattle, sheep, and goats that nibble borage end up taking in pyrrolizidine alkaloids that quietly wear on the liver across weeks and months. Sluggishness, dropping weight, and poor condition are the signs of that slow damage. Keep it well away from grazing ground.
Birds Toxic
Those same liver-toxic alkaloids make borage foliage a bad pick for poultry and pet birds, so just leave it off the menu.
People Edible in moderation
The young leaves and blue flowers are a well-known kitchen herb, perfectly fine to enjoy now and then for their cool, cucumber flavor. The thing to watch is the pyrrolizidine alkaloids, which can put stress on the liver with heavy or steady use, so think of borage as a garnish rather than 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
There really are only a couple of forms of borage, and flower color is mostly what tells them apart. Both grow and taste the same.
Borago officinalis (common borage)
This is the everyday species, the one with the bright blue, star-shaped flowers and prickly, cucumber-flavored leaves that pops into your head when someone says borage.
Borago officinalis 'Alba' (white borage)
This one swaps the blue blooms for crisp white ones, and apart from that it's exactly the same plant.
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 pretty much plants itself, so seed is the only method that counts and honestly the only one you'll ever need.
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
Pop borage seed right into the spot where you want it to grow, because that deep taproot really doesn't like being moved. Hold off until after the last spring frost and the soil has warmed up, then the seeds sprout in 1 to 2 weeks and bulk up over the next few. Once it's comfortable, it'll keep sowing itself for years.
Myths
Borage is a completely safe culinary herb you can eat in any amount.
The leaves and stems hold pyrrolizidine alkaloids that can hurt the liver if you eat a lot of them or keep at it over a long time. An occasional garnish of flowers and young leaves is fine, but think of borage as a flavoring rather than a staple green.
Planting borage once is enough because it's only an annual.
Sure, it dies back every year, but it scatters so much seed that it shows up again on its own, season after season. Leave it to set seed and one plant can fill a whole bed and start acting weedy.