- Latin synonym: Ledum palustre
- Name also: Wild Rosemary, Marsh Tea, Marsh Labrador Tea, Northern Labrador Tea, Wild Rosemary (in parts of USA)
- Family: Heather Family – Ericaceae
- Growing form: Perennial dwarf shrub.
- Height: 30–100 cm (12–40 in.). Stem erect, branched, woody, brown.
- Flower: Corolla regular (actinomorphic), white, 10–15 mm (0.4–0.6 in.) broad; petals 5. Sepals 5, very small. Stamens 10, long. A single carpel. Inflorescence an erect, long-stalked umbel; flowers strongly fragrant.
- Leaves: Alternate terminating shoots, short-stalked, overwintering, strongly fragrant. Blade linear, thick, leathery, underside with rust-brown hairs, with entire, revolute margins.
- Fruit: With glandular hairs, nodding capsule, 5-valved, opening from base.
- Habitat: Bogs, swamps, peat-covered areas, sometimes forest heaths.
- Flowering time: June–July.
Labrador tea usually grows around bog margins, forming wide, quite united stands. Walking through the flowering brush is an experience, not just for the abundant display of flowers but also for the heady aroma. Labrador tea’s aroma comes from essential oils such as ledol, palustrol and myrcene. These compounds repel cattle and large mammals, and can give sensitive people a headache. Despite its toxicity it has been cleverly used to flavour beer, instead of or alongside hops. Essential oils stimulate the central nervous system, so drinkers can become sexually excited or quarrelsome troublemakers. This quickly passes however and is replaced by apathy. A consequence of all this is, in the best case, a shocking hangover – in the worst case it can destroy your kidneys in one fell swoop. An infusion of the plant has also been used to wash insect vermin from clothes and get mice out of the house. It also yields a strong yellow dye, but it has economically unfortunate qualities because it can destroy spruce trees by passing on spruce-Labrador tea needle rust. Labrador tea is the official flower of the province of Northern Ostrobothnia.