The crowberry is a 10–30 cm tall shrub with overwintering, unstalked leaves which are 3–7 mm in length, needle-like and hollow. The underside of the leaf is split by a light-coloured line. The flowers of the crowberry are red, axillary, and bloom in May–June. The berry itself is a glossy black drupe.
Finland is home to two types of crowberry. The mountain crowberry (E. nigrum ssp. Hermaphroditum) is monoecious, and dried stamens can often be found at the base of the berry. The berries are plump and grow in great quantities. The leaves of the mountain crowberry are dark green and the light-coloured line on the underside of the leaf is clearly depressed. The common crowberry (E. nigrum ssp. Nigrum) is dioecious, prostrate, with no stamen remains at its base. The crop of crowberries is usually quite modest and the berries are fairly small. The leaves of the shrub are yellowish-green and the light-coloured line on the underside of the leaf is not depressed.
The crowberry grows primarily in xeric, sub-xeric and mesic boreal forests and on hummocks in string bogs.
The crowberry has a long picking season. It can be harvested from the end of July until the first snow. The best picking time is in early August. As the berry overwinters, it can be picked in spring as well. The biggest crops of crowberries are found in northern Finland, Ostrobothnia and North Karelia. The crowberry blooms and produces berries most successfully in sunlit, sparsely wooded or open barren and xeric heath forests.
The crowberry is a good source of fibre. The same amount of fibre is contained in 100 grams of crowberries as in 50 grams of raisins, for example. An excellent health benefit of this berry is the amount of anthocyanin compounds it contains, close to the amount found in wild bilberry. Studies have also shown that the crowberry contains proanthocyanidins, which are especially abundant in lingonberries.
Crowberries can be made into a delicious juice by themselves, or used for a mixed berry juice together with bilberries, alpine bearberries, bog bilberries and blackcurrants. The mild flavour and bluish-purple colour it adds to food make it a suitable raw ingredient for baked goods, berry soups, porridges and milkshakes, either on its own or combined with other berries. Crowberries can also be used to make jam, jelly or marmalade.