If you live in the North and are searching for a new and unusual crop or landscape plant, consider lingonberries. These plants thrive in moist, acidic soils from Massachusetts to Alaska, producing an abundance of healthful, cranberry-like fruits.
The lingonberry is a 12- to 18-inch-high evergreen shrub native to northern temperate, boreal and arctic regions of Europe and North America. In addition to inherent cold-hardiness, once covered with insulating snow, it survives northern winters from New England to Minnesota. In fact, it's one of the few fruits that gardeners can grow successfully in those cold climates. In warmer climates, such as USDA Hardiness Zones 9 and 10, lingonberry neither grows well nor reliably survives summer.
Lingonberry plants spread by underground runners to three feet. The glossy, dark green leaves are 1/8- to 1/2-inch long and usually tinged red when new. This shrub is handsome enough for ornamental use -- as a small-scale ground cover or informal edging around larger acid-soil plantings, for example. It is also attractive in containers.
The wild North American species of lingonberry, Vaccinium vitis-idaea var. minus (also called the mountain cranberry) is a low-growing plant that blooms only in the spring; the European and Asian native, V. v. var. majus, is a slightly taller shrub with larger leaves and flowers. It blooms twice each season. Also called cowberry or foxberry, it's the type more commonly found at nurseries. Dan Hartmann, of Hartmann's Plantation in Grand Rapids, Michigan, notes that this potential for a double crop is part of what makes these plants attractive.
Small, pinkish white, lily-of-the-valley-like blossoms open in tight clusters near the tips of one-year-old shoots and make an attractive display in border plantings. The May bloom produces fruits that ripen in midsummer (July and August here in northern Maine). The summer bloom, which occurs when fruits from the first bloom are ripening, produces fruits that ripen in late September and October.
Open flowers are only hardy to about 30°, meaning the first bloom is usually nipped by a late frost. The second crop is usually the largest and often the only one of the season. This is not as bad as it sounds, however. In my experience, fruits that ripen in the cooler temperatures of fall generally have the best color and flavor.
Lingonberries are self-pollinating, but cross-pollination will produce larger fruits that ripen earlier. Besides, mixing fruit of several varieties will tickle your palate with all the fine, tart nuances of lingonberry flavor.
Bumblebees are the best natural lingonberry pollinators. Plants need two to three years to begin bearing good crops, according to Diana MacKentley of St. Lawrence Nurseries in Potsdam, New York. But when the time comes -- usually just in time for Thanksgiving -- better have your recipes ready.
Lingonberries are slightly smaller than cranberries but otherwise look and are cooked the same. Flavor, however, is distinct. Pick the firm, deep red fruits and refrigerate immediately; sound fruit will keep for up to three weeks. Or wash, drain and freeze them for use later in the season.
These fruits are tart. Make them into jam for a superb roast goose and venison topping. Pancakes covered with lingonberry syrup are a Swedish tradition. Use them in any recipe that calls for cranberries. Lingonberries are very rich in vitamin C -- Scandinavians and native tribes of northern Canada use the fruit as a cold remedy. The simplest preparation is lingonberry sauce: 3 cups washed fruits, 1 1/4 cups sugar and 1 cup water. Boil 10 minutes; skim and cool.
Locate your planting in a sunny spot on land with good air circulation and soil drainage. My lingonberry garden has a southeastern exposure. It receives sun most of the day and yet is protected from the brutal northwest winds of winter by a thick blanket of drifted snow. The plants grow well in the acid soils of our region. The ideal is soil of pH 5 that is also high in organic matter.
According to research by Dr. Elden Stang, professor of horticulture at the University of Wisconsin, plants grow best when up to about seven pounds of peat moss is incorporated into each 100 square feet of row. Adding more does not increase plant growth substantially. Dr. Stang's research plots were located on a loamy sand soil. In your garden, work in the peat moss or compost and adjust the pH during the fall prior to spring planting.
Order your plants early from a reputable nursery. Start with plants in either two-inch or one-gallon pots. Set them out after danger of severe spring cold has passed and the soil has dried sufficiently to be worked. In my garden, on the border of zones 4a and 3b, that's late May.
Make the planting hole wide enough to accommodate all the roots without bending and set the plants as deeply as they grew in the pots, about 12 inches apart in rows spaced about 36 inches apart. Water them thoroughly to settle the soil about the roots.
By the second season, the plants will begin to spread, sending up shoots increasingly distant from the crown. In this respect, their growth habit resembles that of another cousin, the lowbush blueberry. The aim is to establish a hedgerow of plants about 18 inches in width.
According to MacKentley, weeds are the single biggest pest of small lingonberry plants. The best prevention is a two- to three-inch-deep mulch of sawdust, pine needles, chopped straw or peat moss that smothers young weeds. Otherwise, there is little the home gardener can do but pull them by hand and risk injuring the shallow roots of the new plants.
Mulched plants produce stronger growth and up to quadruple the yields of unmulched plants. Peat moss is far superior to sawdust or chopped straw, probably because it simulates the lingonberry's natural soil environment. Place it a couple of inches deep around the young plants right after planting, and increase the thickness of this layer each year as the plants grow in height. Several inches of damp peat moss make a wonderful mulch for mature plants, and the plants' rhizomes will actually spread through its lower layers.
Lingonberries require little fertilizer. In fact, excessive nitrogen will overstimulate vegetative growth and decrease fruitfulness. It may also interfere with hardening and increase winterkill.
How much is enough? If shoot growth seems vigorous and new shoots grow several inches and remain erect and rigid, fertility is about right. If growth is soft and rampant, with large dark green leaves, you have overfertilized. If shoots are short and the foliage is pale yellow or red during the growing season, plants need some fertilizer. In the North, I make it a rule to apply no fertilizer to fruit plants after the Fourth of July. Most woody plants have completed shoot growth by then, so the fertilizer will do little good. It could, however, stimulate excessive late growth that may not harden in time for winter.
Generally, a small handful of a complete fertilizer, such as 5-10-10, applied in a circle around a mature plant in the early spring, will be sufficient. Use smaller amounts for plants up to about three years old. Fish meal or dried blood are good organic nitrogen sources, but be sure to apply them very early in the spring. Precise amounts depend upon the site and vigor of the plants. If you pay enough attention to them, the plants will always tell you what to do.
Lingonberry, like its cousins, is sensitive to chlorides. Keep de-icing salt, water from chlorinated pools and fertilizers containing potassium chloride away from them.
Propagate plants in spring by splitting and separating a crown and transplanting clumps. It helps older plantings that have become crowded and unproductive. Plunge your spade deep, severing the plant's root system and rhizomes. Lift the plant portion gently and transplant it to another area. That's all there is to it. The only trick is to be sure that you leave part of the rhizome attached to the clump. Without it, the plant will not spread rapidly.
Except for the occasional removal of dead and damaged shoots every spring, lingonberries require no pruning.
Introduced in 1981, this is a very vigorous grower producing exceptional crops of large, light red fruits. It's mild-flavored, in contrast to tart and tangy Koralle.
This Dutch variety is the most popular and provides most European commercial production. Attractive plants are upright and vigorous. The small to medium-sized fruits are highly flavored but somewhat tart. Often fruits of Koralle are blended with those of a more productive but mild-flavored variety such as Sussi.
This recently introduced (1983) Dutch variety produces large, mild-flavored fruits and appears to have resistance to Phytophthora root rot. Fruits ripen one to two weeks earlier than Koralle.
Selected by Dr. Elden Stang from seed collected in Finland, Regal is noted for its superior fruit size and early bearing.
This new Norwegian introduction produces some fruit but is mostly noted for producing abundant pollen, which makes it a valuable pollinator.
This Swedish variety is slow to establish but ultimately produces large red fruits abundantly.