A spreading perennial, growing on a creeping rhizome, about 40 cm (16 in) tall, it has four-angled stems, whorls of rough-textured, lance late leaves and a mass of tubular, star shaped, scented, white flowers in summer.
History and traditions
A strewing herb since medieval times, it is one of many species containing compounds which release coumarin, with its characteristic scent of new-mown hay, as the plant dries. Thomas Tusser called it “sweet grass” and recommended it for making a water to improve the complexion as well as for strewing. Gerard recommended it as a kind of air conditioning: “The flowers are of a very sweet smell as is the rest of the herb, which, being made up into garlands or bundles, and hanged up in houses in the heat of summer, doth very well at temper the air, cool and make fresh the place” (The Herball, 1597). The dried leaves were put into sachet mixtures to deter moths, used to stuff pillows and mattresses and placed between the pages of books.
Growth
Grow in humus-rich soil in partial shade. Propagation is easiest by division of runners in spring or autumn. Can also be grown from seed, sown as soon as ripe in late summer.
Uses
Medicinal
Coumarin gives it sedative properties and infusions are taken for nervous irritability and insomnia. Modern research has found that two of its coumarin molecules join to produce dicoumarol, which prevents blood clotting and strengthens capillaries, and it is taken internally for varicose veins and thrombophlebitis. It is a diuretic and said to improve liver function and have a tonic effect on the system.
Aromatic
The coumarin smell intensifies and improves with keeping, so the dried herb is added to pot-pourri or sachets for the linen cupboard it helps repel insects.
