AT A GLANCE
- Common Name: Bog Rosemary
- Scientific Name: Andromeda polifolia
- Category: Plants
- Subcategory: Flowering Plants
- Range: Circumboreal across northern and cold-temperate regions of the Northern Hemisphere, in northern Europe, northern Asia, and northern North America
- Habitat Type: Acidic, wet Sphagnum peat bogs, raised bogs, quaking mires, and cold boreal muskegs
- IUCN Red List Status: Least Concern
- Lifespan: Perennial evergreen dwarf shrub (lives 15 to 30 years)
- Diet: Autotrophic (photosynthetic, aided by ericoid mycorrhizal root fungi)
- Average Size/Weight: Height 10 to 40 cm; spreading dwarf shrub
- Key Defining Feature: Delicate evergreen bog shrub with narrow, rosemary-like blue-green leaves with chalky-white undersides, crowned with drooping clusters of exquisite pale pink, porcelain-like urn-shaped flowers
Overview
Bog Rosemary (Andromeda polifolia) is an enchanting and delicate evergreen dwarf shrub native to the wild, waterlogged Sphagnum bogs of the Northern Hemisphere. Belonging to the heather family Ericaceae, it was famously named by Carl Linnaeus after the mythical Greek maiden Andromeda, who was chained to a sea rock, as Linnaeus saw the delicate plant clinging to treacherous bog mounds surrounded by dark water. Opening clusters of exquisite, waxy pink lantern blossoms in late spring, it is a botanical jewel of the northern wilderness.
Biology and Physical Characteristics
Andromeda polifolia has creeping underground rhizomes that send up slender, wiry, erect stems reaching up to 40 cm in height. Its leathery evergreen leaves are narrow, lance-shaped, 15 to 35 mm long, with tightly rolled-under (revolute) margins that strongly resemble culinary rosemary (Rosmarinus officinalis), though it is not related. The upper leaf surface is a lustrous dark blue-green, while the underside is coated in a chalky, powdery white wax that reflects intense sunlight and reduces moisture loss. In May and June, the branch tips bear nodding umbels of two to eight porcelain-like, urn-shaped (urceolate) flowers of soft blush-pink or delicate candy-pink, each opening via five tiny reflexed lobes.
Behavior and Ecology
Bog Rosemary is strictly adapted to cold, nutrient-void, highly acidic peat bogs. It thrives rooted directly in living hummocks of Sphagnum moss, surviving severe winter freezes beneath deep snow blankets. To obtain nitrogen and phosphorus in acidic peat, its root system is enveloped by specialized ericoid mycorrhizal fungi. Like many ericaceous plants, its leaves and stems contain toxic diterpenoids known as grayanotoxins (andromedotoxin), which prevent moose, deer, and caterpillars from browsing its evergreen foliage, but make the plant dangerously poisonous to domestic sheep and cattle.
Conservation and Human Impact
The Bog Rosemary is classified as Least Concern on the IUCN Red List due to its immense circumpolar distribution across the boreal muskeg of Canada, Alaska, Scandinavia, and Siberia. However, in the southern parts of its range across Western and Central Europe (such as the UK, France, and Germany), it is critically endangered or locally extinct in many lowlands due to catastrophic historical peat cutting, bog drainage, and commercial forestry.
Interesting Factoid
Carl Linnaeus named this plant ‘Andromeda’ because its delicate pink flowers chained to a lonely mossy bog mound reminded him of the mythical princess Andromeda chained to a rock in the ocean awaiting rescue.