Bog Myrtle
Myrica gale
Smell it when you are knee-deep in Highland water and you will understand everything.
Overview
Bog myrtle is the scent of the Highland bog — a small, deciduous shrub of waterlogged, acid ground that releases, when a leaf is crushed, a smell so immediate and so specific that it bypasses description and goes directly to sense memory for anyone who has ever stood in a Scottish peat bog in summer. It is the smell of the midge season: the plant and the insect share the same territory, and bog myrtle is the traditional repellent, rubbed on exposed skin, woven into hats, tucked into clothing. Before hops came to Britain in the fifteenth century, bog myrtle was one of the primary bittering agents for ale — part of the gruit blend used across northern Europe, a mixture of herbs that flavoured, preserved, and, in the tradition of those who have examined it closely, may have added something more to the drink than flavour.
Botanical Notes
A deciduous shrub reaching 50–150cm with grey-brown stems and narrow, oval, dull green leaves that are covered in resinous yellow glands visible as dots when held to the light, intensely fragrant when crushed. Catkins appear before the leaves in April; male and female catkins on separate plants. Small, waxy, resinous fruits in late summer. Found in bogs, wet heathland, and wet moorland — acid, waterlogged, nutrient-poor soils — throughout northern Europe, particularly in the Scottish Highlands, Ireland, and Scandinavia. The resin contains myricine, terpenoids, and other compounds; the exact chemistry of any psychoactive effect at gruit concentrations remains debated.
Lore & History
Gruit ale — the ale of pre-hop northern Europe — was a controlled substance in its time: the Gruitrecht, the right to sell the gruit blend, was held by the Church or by secular lords, and the income from it was substantial. The blend varied by region but commonly included bog myrtle, yarrow, and wild rosemary (Rhododendron tomentosum, not the culinary herb), and possibly henbane. The claim that gruit ale was psychoactive — that the herbs added something beyond bitterness — has been made seriously by historians of brewing and herbalism, with bog myrtle and wild rosemary as the primary candidates. The evidence is circumstantial but consistent. The Scots called it roid or gale; it was one of the plants worn at Highland weddings. In Norway it was woven into the bridal crown.
Warnings
Avoid during pregnancy — bog myrtle has documented emmenagogic effects and was used historically to induce miscarriage. The resinous compounds may be mildly neurotoxic in quantity; do not consume large amounts of the foliage. As a culinary flavouring in small quantities (beer, cooking) it is generally considered safe. The essential oil is not for internal use. Those on anticoagulants should exercise caution — some constituents have blood-thinning properties.