Borage is an annual herb grown for its edible blue star-shaped flowers and cucumber-flavoured young leaves. The flowers go into drinks, salads and ice cubes; the plant itself is one of the best bee plants in the garden, refilling its nectar every few minutes so bumblebees and honeybees work it from morning to dusk. It is often grown among vegetables for that reason.
It is quick from seed and resents transplanting because of its taproot, so sow it directly after last frost, a half inch deep, and thin to 12 to 18 inches. It takes full sun and poor soil and needs little water once up. The hollow, bristly stems reach 18 to 24 inches and flop without support or close spacing; let the plants lean on each other or on a neighbour. Pick flowers by the dark stamens so the blue star comes away whole.
It self-sows freely and returns every year once you have it, which is a feature or a nuisance depending on the bed; pull the volunteers you do not want when they are small. The leaves are hairy and only the youngest are pleasant raw. Deer leave it alone. It is native to the Mediterranean.
Powdery mildew
White or grey powdery coating on leaves - usually starting on older growth in humid conditions or when nights cool.
Improve air circulation by thinning plants. Apply neem oil or potassium bicarbonate spray at first sign. Avoid overhead watering.
Root rot
Plants wilt, yellow, and stunt even in moist soil; lower stems and roots turn brown, soft, and mushy and the plant may collapse. Most common in heavy, wet, or poorly drained ground.
Improve drainage and stop overwatering, and never plant too deep. Lift and destroy badly affected plants along with the soil around the roots. Grow in raised or free-draining beds to prevent it returning.
Aphids
Aphididae →Clusters of small soft insects on new growth and flower buds.
Knock off with a strong jet of water. Ladybirds and lacewings are natural predators. Insecticidal soap as last resort.