Low-growing, fragrant shrub, growing to 6½ ft (2 m), with lance-shaped leaves. Male plants produce resinous catkins in spring.
Habitat & Cultivation
Sweet gale thrives in wet and damp heaths and moorlands across northerly regions of the northern hemisphere. The leaves are collected in summer, the catkins in spring.
Leaves, branches, catkins.
Sweet gale contains an essential oil (chiefly alpha-pinene and delta-cadinene), flavonoids, and resin.
History & Folklore
In Scotland, where the plant grows freely, Highlanders slept on fleaproof beds of sweet gale and placed it among linen to repel moths. Enterprising anglers are also reported to have worn sprigs of sweet gale to keep away midges. In Scotland and Sweden, a strong decoction was used to kill insects and intestinal worms.
Medicinal Actions & Uses
Sweet gale is mostly used as an insect repellent and insecticide and offers a safe and ecologically sound way to protect against insect bites. Over-the-counter preparations are available, though a decoction of the plant bathed on exposed areas will also prove effective.
Since the 1990s, the essential oil of sweet gale has become recognized as an effective insect repellent (especially of midges), and is now available in blended formulations. In one trial in Scotland, volunteers exposed their arms to midges, with one arm covered in a gel containing essential oil of sweet gale. After 10 minutes, the protected arms averaged 1.6 bites, the unprotected arms 9.4.
Do not take the essential oil internally. Do not use sweet gale internally in pregnancy or while breastfeeding. The essential oil is thought to be toxic.