What it is
Sweet grass, Hierochloe odorata or Anthoxanthum nitens, is an aromatic herb native to Northern Eurasia and North America. Many Indigenous peoples in Canada and the United States consider it sacred. It is a very hardy perennial, able to grow in the Arctic Circle. The leaves lack rigid stems, so they reach only about 20 cm in height before growing outward horizontally to 100 cm long or more by late summer. In the wild, the bases of the leaves are frequently purple-red, which indicates a phosphorus-deficient soil.
Hierochloe means "holy grass" and odorata means "fragrant". Some authors include Hierochloe in Anthoxanthum; in that case this species is given the epithet nitens.
Distribution and ecology
In North America it occurs in southern Canada, the northern Great Plains and Rocky Mountains, the northwest of the U.S., and New England. In continental Europe it occurs north from Switzerland. It is a marshland species occupying the middle range of habitat between dune and salt marsh ecosystems.
Chemistry
Two chemicals found in sweetgrass, phytol and coumarin, repel mosquitoes. Of the sweetgrass extracts tested, the steam-distilled oil drew the fewest mosquito bites, matching the repellent potency of DEET. Coumarin has a bitter taste that deters grazers.
Coumarin belongs to the benzopyrone chemical class and is considered a lactone. Its formula is C₉H₆O₂. The tonka seed also contains coumarin. Coumarin was first isolated from tonka beans in 1820. It was first synthesized in 1868 by the English chemist William Henry Perkin.
Harvest and traditional use
The grass is harvested by cutting it in early to late summer at the desired length. Grass harvested after the first frost has little or no scent and is less desirable for basketry. Basketweavers sun-dry cut sweet grass until it is dry and brittle. The brittle grass must be soaked in warm water until it becomes pliable. The pliable grass is typically braided into thick threads and then redried for use.
Holy grass was strewn before church doors on saints' days in northern Europe. Indigenous peoples from many different Nations in North America use sweetgrass. The Haudenosaunee have been known to use it for basketry, ceremonial smudging, incense, perfume, and herbal medicine. Among many of the Indigenous peoples of the Great Plains and Canadian Prairies it is considered one of the "four sacred medicines". For many tribes its two main purposes are to attract good spirits and to repel mosquitoes naturally. It is also known as the "Hair of Mother Earth".
Flavour uses
In Russia, it was used to flavor tea. It is still used in flavored vodka.
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Related: Ammophila Beach Grass · Deer Tongue Grass · Gingergrass · Grass · Hay · Nut Grass · Sabah Snake Grass
