Rosemary

An evergreen shrub, from a low sprawling mat to an upright bush five feet or more, with woody stems and narrow, leathery, needle-like leaves — dark green on top, pale and felted underneath. Small two-lipped flowers, pale blue to deep violet, appear along the stems in late winter and spring and sometimes again in autumn. The smell is resinous, like pine and camphor.

Botanists moved rosemary into the sage genus in 2017, so you’ll see both Rosmarinus officinalis and Salvia rosmarinus; they are the same plant.

The name comes from the Latin ros marinus, “dew of the sea,” for the shrub’s habit of growing on sea cliffs around the Mediterranean. In Spain it is called romero, the pilgrim’s flower, from a legend that it sheltered the Virgin Mary on the flight into Egypt and that its white flowers turned blue where she spread her cloak to dry.

Rosemary stood for memory and faithfulness. Brides wore it and gave gilded sprigs to guests, and mourners threw it into graves; Ophelia says in Hamlet, “There’s rosemary, that’s for remembrance.” In Australia and New Zealand people still wear a sprig on Anzac Day, because rosemary grows wild at Gallipoli.

Hungary water, a rosemary-scented spirit, was said to have been made for a Queen of Hungary who was cured of paralysis by it, a story that is almost certainly legend. Rosemary was burned in sickrooms, and French hospitals burned it with juniper berries to freshen the air.

Rosemary is a Mediterranean hillside plant: full sun, sharp drainage, and not much water once it is settled in. Heavy, wet soil is its main enemy. Most kinds survive winters down to the high teens or low twenties Fahrenheit; hardier varieties such as ‘Arp’ take a little more cold with some shelter.

In colder places, grow it in a pot and bring it into a bright, cool window for winter, watering sparingly. Trim it after flowering to keep it bushy.

‘Arp’ and ‘Madeline Hill’ (sold as ‘Hill Hardy’) are the most cold-tolerant. ‘Tuscan Blue’ and ‘Blue Spires’ are tall and upright; ‘Barbecue’ has straight stems that make good skewers; ‘Prostratus’ trails over walls and pots; and ‘Majorca Pink’ has pink flowers.

It belongs with lavender, sage, thyme, and oregano in a sunny, dry bed. Old gardening advice plants it near carrots, beans, and cabbages to confuse pests with its scent. The evidence for that is thin, but its early flowers are a real help to bees.

Snip sprigs whenever you need them, all year, taking no more than about a third of the plant at once. For drying, cut longer stems before or just as it flowers and hang them in bundles; once dry, strip the needles off with your fingers and keep them whole.

A strong, cooled infusion is the traditional rinse for dark hair. Sprigs went into moth sachets and wreaths, were burned to freshen sickrooms and kitchens, and were carried at weddings and laid on coffins as a token of remembrance.

Rosemary goes with roast lamb, chicken, pork, and potatoes, into focaccia and other breads, and into olive oil, salt, and vinegar. Chop the needles finely or use whole sprigs you can lift out; the flavor is strong, so a little goes far.

The leaves and flowering tops are the parts used. A strong infusion, a tablespoon of leaves per cup steeped fifteen minutes, was a traditional rinse for dark hair and a scalp wash. Weaker, it was drunk as a tea for poor digestion and headaches.

Rosemary oil and infused oil were rubbed into sore muscles and joints, and sprigs were packed with linens and woolens against moths. Rosemary is still one of the most common herbs in European and Mediterranean cooking.

Rosemary’s essential oil is mostly 1,8-cineole, camphor, and α-pinene, with borneol and bornyl acetate. The balance varies so much that growers recognize different chemotypes, such as cineole-rich, camphor-rich, and verbenone types.

The leaves also hold carnosic acid and carnosol, strong antioxidants that make rosemary extract a common natural preservative in foods (it is approved in the EU as additive E392). Rosmarinic acid, found in many mint-family herbs, was first isolated from rosemary and named for it. The leaves also contain ursolic and oleanolic acids and flavonoids.

Two small studies get quoted often. In 2012, researchers exposed 20 people to rosemary oil aroma and found that higher blood levels of 1,8-cineole went with better speed and accuracy on mental tasks, though the study didn’t show cause and effect. In 2015, a trial of about 100 people with pattern hair loss found that rosemary oil and 2% minoxidil both increased hair counts after six months, with no significant difference between them. Neither study has been confirmed by large trials.

European regulators list rosemary leaf as a traditional herbal medicine for indigestion and mild stomach cramps, and, used on the skin, for minor muscle and joint pain and minor circulation problems, based on long use.

Rosemary in cooking amounts is safe. The concentrated oil can irritate skin, and the European monograph advises against medicinal doses in pregnancy, while nursing, and for people with gallstones or liver disease.