Borage

Seed to garden

Sow borage seeds straight into the garden where you want plants, since it does not like being transplanted. Plant after your last frost in most gardens, or in the cool season where summers are hot, covering the seeds about half an inch deep. They come up in one to two weeks. Space plants 12 to 24 inches apart because borage gets big, and it will drop seed and come back on its own.Direct-sow borage where it will grow; it has a taproot and does not transplant well, so starting it indoors is not recommended. Sow after the last spring frost in cool and temperate regions, or in fall and the cool season in hot ones, covering the seed about 1/2 in (it germinates fine in darkness or light, but should be covered). It comes up in 1 to 2 weeks. Thin or space plants to 12 to 24 in, since borage grows large and sprawling, and it self-sows readily for future seasons.

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   Sow outside
   Oct 1 - Nov 30, Feb 1 - Mar 31

Care guide

The numbers that matter, at a glance.

Yes, 3 gallons and up

Borage can grow in a container, but it gets big with a deep taproot, so use a large, deep pot (5 gallons or more) with drainage holes and a well-draining mix in a sunny spot. It is happier in the ground, where it has room to sprawl and reseed.Borage is growable in containers but is better suited to the open ground: it develops a taproot, grows large and sprawling, and self-sows, none of which suit a small pot. If you do container-grow it, use a large, deep pot (5 gallons or more) with excellent drainage, full sun, and a free-draining mix, and expect to stake or let it spill. Keep the mix from staying wet, since borage rots in saturated soil.

Pot size

3 gallons and up; 5 gallons is comfortable

Mature size

2 to 3 feet tall, 12 to 16 inches wide

Drainage

Drainage holes are a must.

Watering

Pots dry out faster than the ground, so check them, but let the top inch dry before watering, because borage does not like soggy roots. Try not to wet the leaves.Containers dry faster than beds, so check them, but never keep the mix constantly wet, which rots the roots. Water at the base to keep foliage dry against powdery mildew.

Depth and shape

At least 10 inches deep.

Self-watering pot

No. Self-watering containers are a poor fit for borage, which prefers to dry between waterings and rots in constantly moist soil; if used, keep the reservoir low so the root zone is not kept saturated.

Mix

General-purpose, free-draining potting mix. Prioritize a free-draining mix in a large, deep container to accommodate the taproot; blend in perlite or coarse sand if the base mix stays wet. Keep fertility modest, since borage grows lush and floppy with excess feeding and rots in constantly wet mix.

Feeding

Frequent watering leaches nutrients, so a light feeding every few weeks during bloom is ample; keep nitrogen modest so the plant does not grow soft and floppy.

Soil pH for borage

Borage is not picky about soil pH (how acidic or alkaline the soil is). A normal garden range of about 6.0 to 7.0 is ideal, and it tolerates soil well outside that, so you usually do not need to change anything.Borage performs best across roughly 6.0 to 7.0 and is broadly adaptable to soil chemistry; extension descriptions record it growing in acid, neutral, and alkaline soils alike (tolerating roughly 5.5 to 8.0). pH adjustment is rarely warranted, so focus on drainage and modest fertility instead.

Watering

Feeding

Borage barely needs feeding and even grows in poor soil. Mix a little compost or balanced fertilizer into the ground at planting and that is usually all it needs. Too much fertilizer, especially the high-nitrogen kind, just gives you a giant floppy plant with fewer flowers.Borage is a light feeder that thrives even in poor soil, so it needs little supplemental fertilizer. A modest amount of compost or a balanced feed worked in at planting is plenty. Excess nitrogen produces soft, oversized, floppy plants that flower less and are more prone to powdery mildew, so favor a balanced or slightly low-nitrogen feed and skip routine feeding once plants are established.

The three numbers on fertilizer (N-P-K) are nitrogen, phosphorus, and potassium. For borage, a balanced one like 10-10-10 is fine, used sparingly; avoid a high first-number (nitrogen) lawn feed, which gives leaves instead of flowers.A balanced ratio such as 10-10-10 worked in lightly at planting suits borage; some growers give a monthly half-strength balanced feed, but a high-nitrogen lawn-type feed only pushes floppy foliage over flowers.

Deadheading borage

Deadheading means snipping off flowers once they fade. Doing it regularly keeps borage blooming for weeks instead of going to seed, and it also cuts down on how much borage reseeds itself. Snip spent flowers off before they drop seed if you want fewer volunteers, or leave a few at the end of the season so it comes back on its own. Picking flowers to eat or for a vase does the same thing.Deadhead or cut borage's spent flowers regularly to prolong bloom; it flowers for many weeks when older flowers are removed and slows once it is allowed to set seed. Deadheading also curbs its prolific self-sowing, so remove spent flowers before seed drops if you want fewer volunteers, and leave a few late heads if you want it to return on its own. Cutting stems for the vase or for edible flowers does the same job.

Companion planting

Borage is one of the classic companion plants, and its superpower is bees. It flowers for a long time and is a magnet for honey bees, bumble bees, and native bees, so planting it among vegetables draws in pollinators and helpful insects. Gardeners traditionally set it near tomatoes, squash, and strawberries: near squash, melons, and cucumbers it helps pollination; near tomatoes and strawberries it is a long-standing companion said to help them along and bring in the beneficial bugs that eat pests like hornworms. Those pest-fighting claims are garden tradition rather than proven fact, so enjoy borage mainly as a pollinator plant. Just give it lots of room, since it gets big and sprawly, and keep it a bit apart from squash so both get airflow, because they can share powdery mildew. Borage's best-grounded companion value is as a premier insectary and pollinator plant: its long succession of nectar-rich blue flowers strongly attracts honey bees, bumble bees, and native bees, along with beneficial predators, which is well documented by extension. Interplanted around squash, melons, and cucumbers it is credited with improving pollination, and it is a long-standing traditional companion for tomatoes and strawberries (West Virginia University lists it among strawberry companions), with grower lore that it improves their vigor, flavor, and pest resistance and draws in predators of tomato hornworm. Those neighbor-benefit and pest-repellent effects are traditional practice rather than trialed results, so they are framed as tradition. There is no biologically antagonistic companion to avoid; site borage for full sun and airflow, give it generous room because it sprawls, and keep it from crowding squash since the two share powdery-mildew susceptibility.

Recommended varieties

The plain blue borage is the classic choice and the best one for bees, and it reseeds itself easily. If you want something different, 'Alba' has white flowers instead of blue, and variegated types like 'Bill Archer' have pretty cream-and-green leaves. They are all the same easy plant with edible flowers and cucumber-tasting leaves, and they all come back from their own dropped seed.For most gardens the ordinary blue species is the one to grow: it is the strongest bee draw, self-sows freely, and gives the classic edible sky-blue stars. 'Alba' is a white-flowered form of the same easygoing plant, useful in white or cottage plantings, and the variegated selections ('Bill Archer', 'Variegata') are grown more for their cream-splashed foliage than for a different flower. All are the same species, are edible-flowered and cucumber-leaved, and come readily from saved or self-sown seed; the simple, open single flowers of every form serve pollinators well.

Vase life

Borage is a plant for the garden, the bees, and fresh use, not for storing like vegetables. Pick young leaves before they get too fuzzy and prickly, and pick open flowers on a dry day. Snap off the fuzzy green part behind each flower before eating it. The leaves taste like cucumber in salads and drinks, and the blue flowers make a pretty garnish or can be frozen in ice cubes. Only eat borage that has not been sprayed, and eat it only in small amounts: borage leaves contain natural compounds called pyrrolizidine alkaloids that can harm the liver if eaten in large or frequent amounts, so keep borage to a garnish or an occasional few leaves. Wear gloves when you pick it because the stems are prickly.Borage is grown for bloom, a top pollinator draw, and edible leaves and flowers, so the refrigerate and freeze fields do not apply as they would for produce. Harvest young, tender leaves before they turn too bristly, and pick fully open flowers on a dry day; pull off and discard the fuzzy green sepals behind each flower before eating. The leaves taste of cucumber and are used in salads, teas, and cool drinks; the blue flowers are a garnish and can be frozen into ice cubes. Use only unsprayed plants, and eat borage in moderation: the leaves contain pyrrolizidine alkaloids, which NC State notes can damage the liver and lungs, so use them only sparingly, and borage also has a diuretic effect in large amounts. Wear gloves when harvesting, since the stems and older leaves are prickly.

Common problems

Pests & diseases