Cranberry

Cranberry wants full sun to partial shade and moist but well-drained, strongly acidic soil, roughly pH 4.0 to 5.5. Although the plant tolerates periodic flooding, vines grown for fruit actually perform best on well-drained ground rather than standing water, and are typically spaced about two feet apart, or roughly a meter apart when grown purely as groundcover.

New plants are raised from stem cuttings, softwood taken in spring or semi-hardwood taken in late summer, or from seed that has been chilled in damp storage for a few months before it will germinate. Once rooted, cranberry dislikes root disturbance and is difficult to transplant, so growers try to site it permanently.

Established vines are intolerant of heat and drought and need roughly three months of winter temperatures near freezing to complete their cycle, yet hard freezes and drying winds can still injure them, so growers protect plantings with flooding or a mulch cover and guard against spring frost. A planting can take about five years to reach full bearing but may then remain productive for decades.

Cranberry can develop chlorosis when the surrounding soil is not acidic enough. Hard freezes combined with drying winds can injure vines and cause leaf drop the following spring unless the planting is protected over winter.

Birds and other wildlife readily feed on ripening berries, so a gardener hoping to harvest fruit rather than just grow the plant as groundcover needs to take precautions to keep the crop from being eaten before it is picked.

Cranberry fruit ripens between August and November, coloring from pale yellow to deep red as it matures. Home growers generally hand-pick the berries, while commercial growers flood their bogs at harvest time so that the berries, which hold internal air pockets, float free of the vines for collection.

Sound, fresh berries bounce when dropped, a simple test of firmness, and growers pick over the harvest to discard any fruit that has gone soft, withered, or spotted before it is cooked or stored.

Culinary: Cranberries have long been cooked with sugar into a sauce served alongside roasted meat, and later uses expanded to pies, jellies, jams, preserves, puddings, marmalades, ketchup, juice, and dried fruit.

Ornamental: Because it forms a dense, glossy evergreen mat, the plant is also grown as a groundcover or edging plant for boggy, acidic corners of a garden, giving year-round foliage interest as well as fruit.

Historical: Native peoples of northeastern North America harvested cranberries for food, medicine, and dye for thousands of years, and by 1672 the English writer John Josselyn recorded that both Native Americans and English settlers boiled the berries with sugar as a sauce for meat and regarded them as useful against scurvy and feverish complaints.

Cranberry is native to wetlands and bogs of northeastern North America, where it grew wild in moss-covered marshes long before cultivation. It began to be grown commercially in 1816 in Massachusetts, marking the shift from a wild-gathered wetland plant to a deliberately cultivated bog crop.