Troubleshooting
Borage problems — and how to fix them
Borage (Borago officinalis) is generally forgiving once you match its basics, but a few issues come up again and again. Here is what each one looks like, why it happens, and the fix.
Powdery mildew
The hairy leaves are prone to white powdery mildew, especially late season in humid air. Space plants, water at the base, and remove affected lower leaves.
Flopping and lodging
Tall, soft growth (worse in rich soil or shade) splays and breaks. Grow in lean soil and full sun, or give a light support; deadhead to keep plants tidy.
Aggressive self-seeding
A single plant drops abundant seed and reappears everywhere. Pull spent plants before seed ripens, or harvest seed heads, to control spread.
Black aphids on stems
Blackfly cluster on flowering tips and soft stems. Blast off with water or tolerate them, since borage's flowers draw aphid predators like hoverflies and ladybirds.
Prevent borage problems before they start
Most borage issues are care-mismatch, not bad luck. Dial in the basics:
Looking for borage in general rather than its problems? Read the full borage care guide — light, water, soil and feeding.
Borage problems — FAQ
Why is my borage powdery mildew?
The hairy leaves are prone to white powdery mildew, especially late season in humid air. Space plants, water at the base, and remove affected lower leaves.
Why is my borage flopping and lodging?
Tall, soft growth (worse in rich soil or shade) splays and breaks. Grow in lean soil and full sun, or give a light support; deadhead to keep plants tidy.
Why is my borage aggressive self-seeding?
A single plant drops abundant seed and reappears everywhere. Pull spent plants before seed ripens, or harvest seed heads, to control spread.
Why is my borage black aphids on stems?
Blackfly cluster on flowering tips and soft stems. Blast off with water or tolerate them, since borage's flowers draw aphid predators like hoverflies and ladybirds.