The Borage remains in the garden year after year, as it self seeds itself. Borage should never be moved unless it is very young, as it has a tap root.
It is native to the Mediterranean region and has naturalized in many other locales.
The leaves are edible and the plant is grown in gardens for that purpose in some parts of Europe. Pick nice mature leaves, dip in a batter made from egg, flour and milk, they fry. The leaf plumps up and looks like a fritter. Delicious.
Borage is an old herb, known at least since Roman times.
It is said that borage gladdens the heart, and surely the purple flowers are cheery. But even the small, young leaves are slightly prickly, and the plant may seem rather coarse to a new gardener.
Borage is very useful in the garden. It attracts bees, which increases pollination of nearby plants. Borage may also enhance the growth of tomatoes (by confusing and repelling tomato hornworm); brassicas (by repelling and confusing cabbage worms); and strawberries may do better when grown near borage.
Other plants that seem to improve when grown near borage: cucumbers, beans (including climbing and bush beans), grapes, zucchini/squash, and peas. It is not known to be antagonistic toward any plants.
Borage is also useful as a mulch and in a compost pile. Its leaves and stems contain calcium and potassium which may account for another reason why tomatoes do well near borage. Blossom end rot, which affects tomatoes, is caused by lack of calcium. Potassium helps plants to bloom and set fruit, which may increase production in tomatoes and strawberries. Whatever reasons for planting borage, it is likely to do a lot of good for your garden.
The plant is also commercially cultivated for borage seed oil extracted from its seeds.