|Andromeda polifolia var. polifolia in flower|
Andromeda polifolia, common name bog-rosemary, is a species of flowering plant in the heath family Ericaceae, native to northern parts of the Northern Hemisphere. It is the only member of the genus Andromeda, and is only found in bogs in cold peat-accumulating areas.
It is a small shrub growing to 10-20 cm (4-8 in) (rarely to 40 cm or 16 in) tall with slender stems. The leaves are evergreen, alternately arranged, lanceolate, 1-5 cm (-2 in) long and 2-8 mm (0.08-0.31 in) broad, dark green above (purplish in winter) and white beneath with the leaf margins curled under. The flowers are bell-shaped, white to pink, 5-8 mm (0.20-0.31 in) long; flowering is in late spring to early summer. The fruit is a small capsule containing numerous seeds.
The genus was named by Carl Linnaeus who observed it during his 1732 expedition to Lapland and compared the plant to Andromeda from Greek mythology. The specific epithet is a noun in apposition, which Linnaeus based on Johann Christian Buxbaum's pre-Linnaean generic designation Polifolia. Buxbaum in turn derived the name from Johann Bauhin, who used it to mean "having polium-like leaves". The precise plant that Bauhin meant by polium is uncertain, but it may have been Teucrium montanum. The common name "bog rosemary" derives from the superficial resemblance of the leaves to those of rosemary, which is not closely related.
Numerous cultivars have been developed for garden use, all of which require damp acid soil in shade. The cultivars 'Compacta' and 'Macrophylla' have gained the Royal Horticultural Society's Award of Garden Merit. Like most other members of the family Ericaceae, they are acid-loving plants (calcifuges), and must be grown in a medium with a low pH.