Knäortros

Knäortros is a Swedish common name whose use varies by region and can refer to more than one small evergreen shrub in the Ericaceae family that grow in boreal wetlands and acidic soils. In many floras the term is most often associated with two species, Andromeda polifolia and Empetrum nigrum, though regional usage may differ.

Andromeda polifolia, commonly called bog rosemary in English, is a low-growing evergreen shrub that typically reaches up to a few tens of centimeters in height. It has narrow, waxy leaves and produces pale pink to lilac bell-shaped flowers arranged along the stems in late spring to early summer. The plant forms a dense stand in acidic wetlands such as bogs and peatlands, with a circumpolar distribution in northern Europe, Asia, and North America. Its fruit is a small capsule after flowering.

Empetrum nigrum, known as black crowberry, is a prostrate to spreading evergreen shrub with tiny, firm leaves. It bears small, inconspicuous flowers and black to dark purple, edible berries that persist on the plant into winter. Crowberry favors heathlands, coniferous forests, and bog margins and has a circumpolar boreal distribution across Europe, Asia, and North America. The berries are important for wildlife and have been used by people in some cultures.

Ecology and uses: both species contribute to peatland and heath ecosystems, providing shelter and food for insects and birds. Bog rosemary is sometimes cultivated ornamentally in rock gardens due to its ornamental foliage, while crowberry is valued for its berries, though both can be sensitive to habitat disturbance and climate change. The term knäortros therefore reflects regional naming rather than a single, universally defined species.