Common Name: American Cranberry

General Information

Vaccinium macrocarpon is a creeping, evergreen shrub with long, thin, wiry prostrate stems. Erect or ascending shoots, 4 - 15cm tall develop from the axillary buds, the plant forming a small to large colony[, , ].
The plant has long been harvested from the wild for its fruit which was used locally and also traded. It is increasingly cultivated on a commercial basis in N. America on land that has been adapted so it can be flooded at will[]. The plant is sometimes grown as an ornamental in gardens, where it can be used to form a ground cover.

Known Hazards

None known

Botanical References

, ,

Range

Eastern N. America - Ontario to Newfoundland, south to Tennessee and North Carolina.

Habitat

Acid boggy ground[, ]. Bogs, swamps, mires, wet shores and headlands; at elevations from sea level to 1,400 metres[].

Properties

Edibility Rating
Medicinal Rating
Habit	Evergreen Shrub
Height	0.20 m
Growth Rate	Medium
Pollinators	Insects, Self
Self-fertile	Yes
Cultivation Status	Cultivated, Ornamental, Wild

Cultivation Details

Requires a moist or semi-boggy 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 to 4.5, tolerating up to 6.1; plants soon become chlorotic when lime is present[]. Plants grow best in a poor soil, richer soils result in extra foliage production at the expense of fruit[]. Succeeds in full sun or light shade though it fruits better in a sunny position[]. Requires shelter from strong winds[].
A very dwarf shrub producing long slender creeping stems that root into the soil. Upright stems grow from the axillary buds in the second year and these upright stems flower and fruit the following year[].
Widely cultivated for its edible fruit in N. America, there are many named varieties[, , ]. Cultivated plants are usually grown in artificial bogs that are often flooded in the winter[].
Plants can self-fertilize but cross-fertilization by insects results in higher yields[].
Cultivated plants take about 5 years to come into full bearing but will then crop well for 60 - 100 years[].
On well-prepared ground a crop of 500 bushels per acre has been gathered in a single season[]. A bushel of cranberries is usually 40lb (18.2 kilos) in weight, thus this yield should equal 22 tonnes per hectare[].
Dislikes root disturbance, plants are best grown in pots until being planted out in their permanent positions[].
Plants in this genus are notably resistant to honey fungus[].

Edible Uses

Fruit - raw or cooked[, , , , ]. It can also be dried for winter use[]. Rich in vitamin C[], the fruit is too acid for most peoples tastes to be eaten raw, so it is mainly used in pies, preserves etc[]. It is said that a teaspoon of salt added to the cooking fruit can take the place of half the sugar normally used[]. The red fruit is between 10 and 20mm in diameter[].

Medicinal

An infusion of the branches has been used as a treatment for pleurisy[].

The fruit is antiseptic, antitumor, diuretic and febrifuge. It is taken, especially as a juice, for the prevention and treatment of urinary tract infections, neurogenic bladder, as a urinary deodorizer for people with incontinence, prevention of urinary catheter blockage, and to heal skin around urostomy stomas. It is also used for treating type 2 diabetes, chronic fatigue syndrome, scurvy and pleurisy[].

Cranberry fruits contain anthocyanidins, ellagitannins, flavonols such as quercetin and kaempferol, catechins, and phenolic acids. Other constituents include ascorbic acid, beta-carotene, chlorogenic acid, glutathione, and alpha-tocopherol[].
Cranberry juice is acidic, but does not acidify the urine as previously thought[].
Cranberries contain proanthocyanidins, also known as condensed tannins, and a high-molecular weight compound that has not yet been identified. These constituents seem to interfere with bacterial adherence to the urinary tract epithelial cells. Cranberry, however, does not seem to have the ability to release bacteria which are already adhered to the urinary tract epithelial cells[].
Laboratory evidence suggests that fructose in cranberries might also contribute to the anti-infective activity[].
Cranberry juice has shown antibacterial activity in culture medium against Escherichia coli, Staphylococcus aureus, Klebsiella pneumoniae, Pseudomonas aeruginosa, and Proteus mirabilis[].
Preliminary data suggest that a high molecular weight cranberry constituent might prevent adhesion of plaque bacteria that cause periodontal disease. Cranberry compounds might also prevent adhesion of Helicobacter pylori (H. Pylori) in the stomach[].
Early evidence shows that cranberry juice might increase the antioxidant capacity of plasma[].
There is also preliminary evidence that the proanthocyanidin fraction of cranberry might have anticarcinogenic activity[].
Cranberry, as well as many other fruits and vegetables, contains significant amounts of salicylic acid, which is the active metabolite of aspirin and has anti-inflammatory, antiplatelet, and antitumor effects. Cranberry juice contains about 7 mg of salicylic acid per litre. Drinking three 250 mL servings of cranberry juice daily for two weeks increases serum salicylate levels. It also increases excretion of salicylic and salicyluric acids (a salicylic acid metabolite) in the urine[].

Agroforestry Uses:

Plants can be grown as a ground cover when planted about 1 metre apart each way[]. Plants spread rapidly when they are thriving[].

Other Uses

None known

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 in mid spring of shoots 15cm long, in a sandy mix in a frame covered in plastic to keep them moist[].
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[].