Referred to by the Native Americans as ‘Sassamanesh’, ‘ibimi’ or ‘ataqua’, the cranberry derived its name from the German and Dutch settlers who noted the similarity of the flower structure to that of the crane, a bird they were familiar with from their native lands. As the new name for the fruit, crane-berry, was popularised by missionaries from the mid 1600s, the traditional uses of the plant were celebrated. Variously employed as a juice, fresh fruit, fabric dye, poultice for drawing out poison and medicinal plant, the most popular culinary use was as Pemmican, a preserved sweet meat made from crushed cranberry and deer meats. This is how to Cultivate Cranberries.
Related to our native bilberry, the cranberry is a stoloniferous evergreen of enviably robust constitution, preferring acidic loam soils that retain moisture throughout the year. Contrary to popular belief, cranberries do not grow in water. They are grown on sandy bogs or marshes and because the little fruits float, some bogs are flooded when the berries are ready for harvesting.
Cultivate Cranberries in the home garden
Cultivating cranberries in the garden is remarkably straight forward, in the open sunny locations either in the ground or in containers, but crops are most successful when a special planting pit is created. In a well drained part of the garden, excavate a pit 30cm deep and 1m square. Line the sides and base with a polythene sheet, perforated to allow excess water to drain out. Line the base with granite stone chippings (avoid replacing these with alkaline gravel as this will increase the pH). Place a permeable weed membrane over the gravel before backfilling the space with ericaceous compost. A bed of 1m square will be sufficient size, at least initially, to accommodate three young container grown plants.
As a stoloniferous it is important to provide good surface rooting conditions around the base of the plant, this is best achieved by mulching the entire bed with 2cm of washed, lime-free, sharp sand. This fine layer will also assist moisture retention in the compost below. Water well throughout the season to get plants established, especially in spring and early summer as growth, flowers and fruiting is initiated. This is best done with rain water unless you are sure tap water is sufficiently acidic. Fruiting will begin in the first year, but achieve good levels by the third at which time it is worth trimming the plants to avoid congestion. After fruit picking in autumn, shear the tops down by up to one third, trim to maintain plants within the allotted bed and if necessary, prune out the older, woody stems just above ground level to maintain a carpet of fresh stems and foliage.
Maintaining acidity of the soil is the key to success, so annually apply a top dressing of ericaceous compost and then reapply the sand mulch. It is also worth deploying a sprinkling of Flowers of Sulphur, a sulphur soil conditioner so-called as the crystals appear like inflorescences under a microscope. Apply in spring mixed with the top dressing compost for best results.
Although the species is a generous fruiting plant, there are several cultivars worthy of consideration. ‘Pilgrim’ is a self-fertile form, remaining low to the ground and reliably producing deep, red fruits from September. ‘Early Black’ performs well for a dark fruiting form; ‘Franklin’ is a slower growing red type that works well within the confines of pots and containers. Also offered for sale are plants of the British native cranberry, Vaccinium oxycoccos which is a very tough, smaller fruiting species but is still great for garden cultivation.