Wintergreen

Wintergreen, Gaultheria procumbens, is a low creeping evergreen shrublet of the acid woodlands of eastern North America, bearing white bell-flowers, scarlet berries and glossy aromatic leaves that persist through winter, the trait that names it. Native peoples of the region gathered its leaves for a fragrant tea and chewed them, and the settlers took up the same uses; it is also called checkerberry and teaberry. Its evergreen endurance through the snow gave it, like holly and ivy in Europe, a quiet association with life persisting through the dead of the year.

Its flavour became one of the defining tastes of North American confectionery: wintergreen was a standard flavouring for chewing gum, hard candy and soda well before synthetic methyl salicylate made the flavour cheap to reproduce, and the taste remains far more familiar in the United States and Canada than in Britain, where the same compound is known mainly from muscle liniment, a genuine transatlantic split in how one plant chemical came to be read as either a sweet or a medicine. The plant also readily colonises recently burned or logged acid woodland, one of the first low shrubs to return, so that a patch of wintergreen can itself be a quiet sign of a forest's slow recovery.

The plant is the original source of oil of wintergreen, whose sharp, penetrating scent is almost pure methyl salicylate; the same compound is now made synthetically for flavouring and liniments. That concentrated oil is genuinely dangerous, highly toxic if swallowed even in small amounts, since a teaspoon contains the salicylate of many aspirin tablets, a fact stated here plainly as caution, not as any encouragement to use. The historical medicinal use of the mild leaf-tea is recorded as folk history only. In the modest language of plant correspondence wintergreen carries associations of protection and renewal, read from its evergreen persistence and its clean, reviving fragrance.

Because methyl salicylate is absorbed readily through the skin, modern clinical toxicology has documented genuine cases of salicylate poisoning from the overuse of wintergreen-scented liniments and muscle rubs, not only from swallowing the oil, a caution that belongs alongside the ingestion warning above. The same chemistry links wintergreen to the aspirin family of drugs, since methyl salicylate is metabolised in the body to salicylic acid, the same active principle later isolated from the willow and from meadowsweet, so that a plant valued by Native American and settler herbalists alike for easing aches was, without either group knowing why, working through the pathway modern medicine would eventually explain.