How to Grow Borage USA

At a Glance

Quick Facts

Factor	Value
Drainage	well-drained; tolerates chalk, clay, loam, and sand

Soil & Growing Conditions

Water: does best in dry, sunny places once established; tolerates poor/dry soil

Growth Stages

Stage	BBCH	Notes
Sowing and germination	0	Sow in April in seed trays or pots at about 59°F (15°C), or direct sow outdoors in spring; germination takes roughly five to ten days (RHS).
Establishment and spacing	1	Space plants about 50cm apart in full sun or light shade, on any soil that is not waterlogged (RHS).
Vegetative growth	3	Plants grow into an erect habit 50-70cm tall; keep soil moist through summer for the biggest, best plants (RHS).
Flowering and harvest	6	Flowers appear about 10-12 weeks after a spring sowing; pick individual blooms just as they open. Watch for powdery mildew later in summer once peak flowering is over (RHS).

Harvest & Storage

When to pick: Pick blossoms as they open; use leaves fresh, picking young/tender leaves for best flavour (they are seldom dried). Successive sowings at 4-week intervals extend the harvest.

Diseases

Powdery mildew

RHS: "May be susceptible to powdery mildews."

Pests

Slugs

Gastropoda (slugs, various spp.)

RHS: "Foliage may be damaged by slugs and leaf-mining flies."

Companion Planting

Strawberry

beneficial

Fragaria x ananassa

Pollinator attraction

What the research guides add

Borage is an easy annual that comes back by itself.

• An annual from the Mediterranean with bright blue star-shaped flowers; it grows best in full sun but is not adversely affected by light shade, and does well in all types of soil, including poor soil. (NC State Extension)
• Grow it from seed; it is self-seeding and will remain in the garden year after year. (NC State Extension)
• The stems and tender leaves are edible and taste and smell like cucumber, although the leaves lose their flavour when dried. (NC State Extension)
• Cut the plant back by half in mid-summer for new growth in the fall. (NC State Extension)

Borage in the USA: climate data

Dates are the median 32°F freeze dates and freeze-free days from NOAA NCEI U.S. Climate Normals 1991–2020; zones come from the USDA 2023 Plant Hardiness Zone Map (ZIP code of each city centre).

Sources for this section

• NC State Extension: Borago officinalis (Plant Toolbox)

Section researched and checked on 25 October 2026 by the SoilCommander Editorial Team. How we check facts: editorial policy.

Sources

1. NC State Extension - Borago officinalis (Borage)

   Annual reaching about 1ft 7in-3ft 2in tall and 1ft-1ft 4in wide; fits a space under 12in across. Full sun or partial shade. Tolerates clay, loam and sand at acid, neutral or alkaline pH, but needs good drainage and copes with occasional dryness. Grown from seed and self-seeds freely, so it returns year after year once introduced. Strongly attractive to bees and other wildlife. Flowers are used as edible flowers and young leaves in salads, teas and sandwiches, tasting and smelling of cucumber; dried leaves lose the flavour. CAUTION: borage contains liver-damaging pyrrolizidine alkaloids and should be eaten only sparingly; it is hazardous to cats, dogs and horses, and only certified PA-free borage seed oil should be used. Few problems; powdery mildew can occur.

2. University of Maryland Extension - Borage
3. University of Minnesota Extension - Berries, bees, and borage

   2016-2018 field trials.

These 3 sources are specific to this region. The full list of 7 sources behind this guide (Ecological Entomology (Wiley) -- Griffiths-Lee, Nicholls & Goulson, 2020, GBIF, NC State Extension and others) is in the references of our UK guide to borage; they describe the plant itself, which is the same wherever it grows.