Common Name: Cowberry

General Information

Vaccinium vitis-idaea is a dwarf, evergreen shrub growing from a rhizomatous rootstock and forming a dense mat of erect to prostrate stems 10 - 30cm tall[, ].
The plant is commonly harvested from the wild for local use as a food and a medicine, and sometimes also for the commercial exploitation of the fruit[]. It is also cultivated as a fruit crop and is sometimes grown as an ornamental, where it can be used to form a ground cover.

Known Hazards

The leaves contain 5 - 7% arbutin, a compound that is widely used as a skin-lightening agent and moisturizer. Arbutin is glucosylated hydroquinone and may carry similar cancer risks if ingested, although thaes have not been substantiated and there are also claims that arbutin reduces cancer risk.

Botanical References

, ,

Range

Circumboreal through Europe (south to the Alps), Asia (to northern Turkey, northern China and Korea) N. America (to British Colombia, Connecticut)

Habitat

Sunny mountain meadows, boreal taiga in jack-pine stands, muskegs, raised bogs, dry, rocky barrens, lichen woodlands, exposed habitats, heaths, high moors, headlands, tundras, cliffs, mountain summits; at elevations up to 1,800 metres[].

Properties

Edibility Rating
Medicinal Rating
Habit	Evergreen Shrub
Height	0.25 m
Pollinators	Bees, Self
Self-fertile	Yes
Cultivation Status	Cultivated, Ornamental, Semi-cultivated, Wild

Cultivation Details

Vaccinium vitis-idaea is mainly a plant of the colder regions of the temperate zone, experiencing very cold and often long winters with short summers that can range from cool to hot[].
Requires a moist but freely-draining lime free soil, preferring one that is rich in peat or a light loamy soil with added leaf-mould[, ]. Prefers a very acid soil with a pH in the range of 4.5 to 6, plants soon become chlorotic when lime is present. Succeeds in full sun or light shade though it fruits much better in a sunny position[, ]. Requires shelter from strong winds[].
Dislikes root disturbance, plants are best grown in pots until being planted out in their permanent positions[].
Sometimes cultivated for its edible fruit, there are some named varieties[]. 'Koralle' has large and conspicuous berries[]. The fruit hangs on the plant all winter if it is not picked[].
Although self-fertile, the plant fruits much better when a second plant (not a clone of the first) is grown and it is insect-pollinated[].
Fruit yields are generally greater on peat than on mineral soils. Under experimental conditions, plants produced 82 kg per 100 metres sq on peat but produced only 14 kg per 100 metres sq on mineral soil[].
Maximum yields in cultivated stands may reach 8.15 tonnes per hectare[].
The plant hybridizes with Vaccinium myrtillus in northern Europe, producing Vaccinium × intermedium Ruthe[].
Plants in this genus are notably resistant to honey fungus[].

Edible Uses

Fruit - raw or cooked[, , , , , ]. Quite pleasant to eat[]. An acid flavour, they are used like cranberries in preserves and are considered by many people to be superior to cranberries[]. The taste is better after a frost[, , ]. Occasionally the plants bear 2 crops in a year[]. The red berries are around 8 - 10mm in diameter[].
The fruits are sometimes used commercially - they are made into a dry powder for jelly making and occasionally as filling for caramel sweets[].
The fruits has the following composition: sugar 8.57 - 11.8%, free acids 2.2%,[ benzoic acid 0.075%, tannins 0.224%. The benzoic acid accounts for the inhibition of fermentation. This acid is present in the berries in free state as well as in the form of the glycoside vaccinin, a compound of benzoic acid and glucose[].

A tea is made from the leaves[, ]. This should not be drunk on a regular basis because it contains the toxin 'arbutin'[].

Medicinal

The leaves are antiseptic, astringent, diuretic, refrigerant[, ]. They are used in the treatment of gonorrhoea[], arthritis, rheumatism, diabetes and diarrhoea[].
The leaves contain 5 - 7% arbutin and 0.5 - 6% flavanol[].
The leaves are gathered in early summer and dried for later use[].

The mature fruits are eaten fresh or dried as a remedy for diarrhoea[] and as a treatment for sore throats, coughs and colds[]. The juice has been gargled as a treatment for sore throats[].

The plant (the report is not specific if it is referring to the leaves, the fruit or both), is used in the treatment of urinary tract irritation, gout, arthritis and kidney stones[]. It is also used orally as a urinary tract disinfectant, diuretic, and antiviral[].

The plant (the report is not specific if it is referring to the leaves, the fruit or both) contains hydroquinones - these act as a disinfectant in alkaline urine. Probably safe as a short-term treatment, in the long term hydroquinones can cause liver damage[].
The plant also contains arbutin and hydrochinon, these can be mutagenic and carcinogenic if used long term[].

Agroforestry Uses:

The plant is a useful ground cover on acid soils[], spreading by underground runners to form a dense mat of growth[, ]. It needs weeding for the first year or so[]. Plants are best spaced about 30cm apart each way[].
The flowers produce a great deal of nectar and are very attractive to bees[]. The plant is of extra value in that it also produces flowers when spring temperatures are too low for many other flowering plants[]. A good quality honey is produced[].

Other Uses

A yellow dye is obtained from the leaves and stems[].
A purple dye is obtained from the fruit[].

Propagation

Seed - sow late winter in a greenhouse in a lime-free potting mix and only just cover the seed[]. Stored seed might require a period of up to 3 months cold stratification[]. Another report says that it is best to sow the seed in a greenhouse as soon as it is ripe[]. Once they are about 5cm tall, prick the seedlings out into individual pots and grow them on in a lightly shaded position in the greenhouse for at least their first winter. Plant them out into their permanent positions in late spring or early summer, after the last expected frosts.
Cuttings of half-ripe wood, 5 - 8cm with a heel, August in a frame[]. Slow and difficult.
Layering in late summer or early autumn[]. Another report says that spring is the best time to layer[]. Takes 18 months[].
Division of suckers in spring or early autumn[].