How to Grow Borage Canada

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 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 Canada: climate data

Frost dates and frost-free days are the median values for the stations in Environment and Climate Change Canada climate normals with the highest data-quality rating (1981–2010 normals).

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

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.