Highbush cranberry isn’t a true cranberry, although the berries are similar in both taste and appearance. The Latin name is Viburnum opulus var. americanum, which is important to know if you buy plants for growing cranberries for your own consumption or to support wildlife.
Highbush cranberries are multi-stemmed shrubs growing 10–15 feet tall and 10-12 feet wide. Smooth gray branches form arching stems that give the shrub a dense rounded shape, making it a popular choice both for stand-alone specimen plants and for privacy hedges.
Highbush cranberry leaves might remind you of those of maple trees, but they are more wrinkly and the veins are impressed, or sunken. Leaves are glossy green all summer and in fall turn an intense orange, red or purple depending upon the weather in a particular year.
In June, flat-topped clusters of showy white 3- to 4-inch wide flowers cover the shrub. An outer ring of larger, sterile flowers surrounds each flat cluster. The flowers are pollinated by both insects and wind and soon turn into 1/3-inch berries, starting green then going yellowish pink, then orange and finally changing to bright red by early September.
The berries are high in vitamins A and C and fiber and have more antioxidants than blueberries. They can be eaten raw, but most people don’t enjoy the tart, acidy taste. More often they are made into jellies, jams or sauces. You’ll have plenty of time for harvest, because berries hang on the branches until late winter. Birds will eat them, and in fact may clean off an entire shrub in an hour, but not until every other better-tasting food in the vicinity has been eaten, so they aren’t really competition for the berries.
Harvest time is a matter of taste and opinion. Some people think the berries taste better just before the first frost, while others prefer harvesting after one or two frosts. You’ll have to decide for yourself on that one.
There is a European highbush cranberry that looks very similar to the American version, but the European berries taste terrible and the shrubs are subject to aphid damage. It takes a little close-up detective work to tell the difference. The little stem that joins the leaf to the branches is called the petiole. You’ll see little nubby things called petiolar glands where the petiole joins the leaf. If the nubs are rounded, club-shaped or columnar, the cranberry is American. If the nubs are flat on top or slightly dented, it’s European.
Highbush cranberries don’t require much pruning, but if you’d like to shape the shrub or reduce the height, do so immediately after flowering. Removing some of the oldest stems every few years will encourage new growth from the base of the shrub.
If you decide to add a highbush cranberry to your landscape, give it a spot in sun or part shade. They grow fine in most soils, but prefer moist but well-drained soil that is rich and loamy. They are drought tolerant once established.