Galium odoratum, the sweet woodruff or sweetscented bedstraw,[1] is a flowering perennial plant in the family Rubiaceae, native to much of Europe from Spain and Ireland to Russia, as well as Western Siberia, Turkey, Iran, the Caucasus,[2] China and Japan.[3] It is also sparingly naturalised in scattered locations in the United States and Canada.[4] It is widely cultivated for its flowers and its sweet-smelling foliage.[5] [6] [7]
A herbaceous plant, it grows to 30- long, often lying flat on the ground or supported by other plants.
It owes its sweet smell to the odoriferous agent coumarin, and is sometimes used as a flavouring agent due to its chemical content.
The leaves are simple, lanceolate, glabrous, 2- long, and borne in whorls of 6–9. The small (4–7 mm diameter) flowers are produced in cymes, each white with four petals joined together at the base. The fruits are 2–4 mm diameter, produced singly, and each is covered in tiny hooked bristles which help disperse them by sticking temporarily to clothing and animal fur.[8] [9]
This plant prefers partial to full shade in moist, rich soils. In dry summers it needs frequent watering. Propagation is by crown division, separation of the rooted stems, or digging up of the barely submerged perimeter stolons. It is ideal as a groundcover or border accent in woody, acidic gardens where other shade plants fail to thrive. Deer and chickens avoid eating it (Northeast US).
As the epithet odoratum suggests, the plant is strongly scented, the sweet scent being derived from coumarin. This scent increases on wilting and then persists on drying, and the dried plant is used in potpourri and as a moth deterrent. It was, and partially is, used to flavour May wine (called Maibowle or Maitrank in German), sweet juice punch, syrup for beer (Berliner Weisse), brandy, jelly, jam, a soft drink (Tarhun, which is Georgian), ice cream, and herbal tea. Also very popular are sweet woodruff flavoured jellies, with and without alcohol.[10] In Germany, it was and to some extent still is also used to flavour sherbet powder, which features prominently in Günter Grass' novel The Tin Drum.
However, industrial usage of the plant for sweets was prohibited in Germany in 1974, due to coumarin, the flavorant found in woodruff, being toxic to rats and mice in studies. It has however not been found to be harmful to humans, even in large doses, in which it follows a different metabolic pathway.[11] The flavour is still popular for sweets in Germany, but is achieved artificially with 6-methyl coumarin. Products targeted towards adults, such as alcoholic drinks, are still permitted to include coumarin, in limited quantities.[12]
