Borage is a hardy annual herb that flowers during the warmer months and is much loved by bees . When planted in the garden, the lovely bright blue, star shaped borage flowers attract these busy pollinators. The bees then also visit all the other plants you grow, increasing the productivity of the vegetable garden and ensuring good fruiting and flowering. This amazing herb has been cultivated for its culinary and medicinal uses for centuries.
If you do it for no other reason, grow borage to support bees and other beneficial garden insects.
Growth habits and planting needs
Borage self-sows easily and can spread throughout the garden if not managed properly by cutting off the flower heads before they set seeds. The plants can also grow well in pots and these can then be moved to wherever pollination is needed. So consider your own needs before planting.
Borage loves a site in full sun butr will also tolerate part shade and is sown from late spring to early summer. In Sydney, this is from October to December .
Borage is very easy to grow in a variety of soil conditions however, it does like free draining soils and so, a little preparation will ensure the best results. Borage prefers a soil with a pH of 6.6, so test your soil and amend accordingly. Find more information about soil pH at this link.
Dig over the site removing stones and clods to make the soil friable and loose. As the mature borage plant has a long taproot and is not easily transplanted, it is best propagated by seeds sown directly into the chosen position. As the plant can grow to 1m tall, plant in groups so that the plants will support each other and not blow over.
Moisten the soil the day before planting. Sow the seeds to a depth of 5 mm covering lightly with soil and water with liquid seaweed fertilizer. The borage will germinate in 5 -10 days and after true leaves form, they can be thinned to the healthiest seedlings to a spacing of 30 cm and rows spaced about 20 cm apart. As the plants continue to grow thin further as a mature plant can grow to a width of 60 cm wide and will need space to grow properly.
Keep moist to ensure good growth, though avoiding overwatering, especially if grown in pots and apply liquid seaweed fertiliser periodically over the leaves and root area.
Borage plants will mature in 10-12 weeks. Dead head the spent flowers to encourage new growth and extend the life of the plant.
Companion Planting and Composting
Due to its calcium and potassium content, borage is a good companion plant for fruiting plants like tomatoes. It is also grown as a companion with zucchini, squash, strawberries, legumes, spinach, and brassicas. It adds trace minerals to the soil where it grows.
Additionally, borage can deter tomato hornworm and cabbage worm and by attracting bees and beneficial insects, also deters other pests. Borage flowers resemble the tomato flower and so draw pests away from them to itself.
Borage also can be planted as a green manure crop by growing the plants and then slashing them and turning them under just before flowering. As the borage decomposes it enriches the soil with its trace minerals and nitrogen.
The old leaves can be added to the compost or made into a compost tea.
Borage is rich in vitamin C and potassium and has calcium, magnesium, vitamin A and iron and traditionally, the leaves and flowers of borage have been used for centuries in cooking.
One word of warning however before we consider this.
The natural Pyrrolizidine alkaloids found in borage can be toxic to the liver to some people and if taken in large quantities, so some care should be taken before you consume borage. Here is the entry from Plants for a Future on borage:
“The plant, but not the oil obtained from the seeds, contains small amounts of pyrrolizidine alkaloids that can cause liver damage and liver cancer. These alkaloids are present in too small a quantity to be harmful unless you make borage a major part of your diet, though people with liver problems would be wise to avoid using the leaves or flowers of this plant”
Pregnant and breast feeding women should NOT consume borage due to its Pyrrolizidine alkaloids.
In spite of this, borage has been used since ancient times and is still consumed today in many countries. Here are just some of the ways it is used.
The immature, tender leaves (before flowering when stems and leaves become hairy) can be harvested and used raw in salads where they taste like cucumber.
In Italy the leaves are used in soups and minestrone, and after being blanched, as a filling for ravioli, in herb omelettes, battered and then fried or used in place of spinach in some dishes and in vegetarian lasagne and on pizzas.
Borage leaves are used in soups and as a green sauce in Germany.
In Poland it is used as a flavouring for pickled gherkins.
The borage flowers can be used with other flavouring herbs in vinegar and when macerated for a few days or so, will colour the vinegar a faint blue as the flowers become a pink colour. (Use about 20 flowers to 200mls of vinegar).
The flowers can also be used as edible garnishes or frozen in ice cubes or candied as a decoration for cakes and desserts as shown on herbmother.com at this link.