BLUEBERRIES

"Blueberry"
Earliblue

High-bush blueberry (Vaccinium corymbosum), rabbiteye blueberry (V. ashei)

Blueberries are ornamental as well as useful: the rounded bushes may grow 5 to 6 feet tall and have clusters of white 1/4-inch flowers in the spring, rich green foliage that turns deep red in the fall and abundant crops of sweet blue berries about 1/2 inch in diameter in midsummer.

The best blueberry-growing areas of the country are those where the soil is moderately acid. In the eastern part of the country, the area stretches from Maine to Michigan, Wisconsin and Minnesota south to Florida and Louisiana. In the West the best area is the coastal strip west of the mountains from Washington to northern California. In the rest of the country blueberry culture may be difficult, but isolated plants can be grown in many areas by following the special culture method noted below. The most important blueberries in most of the country are the high-bush type. Excellent varieties, in their order of ripening, are Earliblue, Collins, Blueray, Bluecrop, Berkeley, Jersey, Herbert and Coville. Of these named varieties, the ones most suited for the Northwest are Earliblue, Bluecrop, Berkeley, and Jersey. In the southern part of the country from South Carolina to Florida west to Mississippi and Louisiana, rabbiteye blueberries do better than high-bush blueberries. Good varieties, in their order of ripening, are Tifblue, Delite, and Woodard.

At least two varieties of blueberries should be planted, for pollination of one variety by pollen from another is usually necessary to ensure that the bushes will bear fruit. Blueberry bushes will live and bear for 35 to 40 years; an average plant bears 6 to 8 pints of berries annually, but it may bear at least twice that amount if given good care.

HOW TO GROW:

Blueberries do best in acid soil with a pH of around 5.0. The soil should be supplemented with peat moss, which should make up 50 per cent of the soil mixture around the plants. From Zone 5 north, set out the blueberries in the early spring as soon as the ground can be worked; from Zone 6 south, set them out in fall, winter or spring. For berries within three years, buy plants that are 1 to 2 feet tall. Smaller plants, usually sold as one- or two-year-old plants, should be set in a nursery bed for a few years before being set into the garden. If possible, buy blueberry plants with a ball of soil around their roots, for the roots are very fine and hairlike and must be kept moist at all times. Set high-bush plants 5 to 6 feet apart in rows 8 feet apart; rabbiteye varieties should be planted 8 feet apart in rows 8 to 10 feet apart. Cut back both types about halfway at the time of planting.

Immediately after planting, mulch the soil with about 4 inches of old sawdust, wood chips or ground bark. Retain at least this much mulch at all times, increasing the depth on mature plants to as much as 8 inches.

Blueberry bushes should be pruned during their dormant season in winter or early spring. Remove thin, weak growth and old wood--the largest fruit are borne on the fresh new canes. Some varieties bear so many berries that nourishment is exhausted and the fruit are undersized. To avoid this problem, cut back the tips of canes so that only four or five fat flower buds are left on each twig. Pick off all blossoms the first two years and allow only a small crop to mature during the third season. Thereafter the crop will increase gradually each season until the plants reach maturity in 8 to 10 years.

In areas where the soil is alkaline, having a pH of 7.0 or above, plant blueberry bushes in containers sunk into the ground. Two very satisfactory containers can be made by cutting one 50-gallon metal drum in half, then punching three or four 2-inch holes in the bottom of each section for drainage. Sink the drums into the soil to within 1 inch of their rims and fill them with an acid type of peat moss, such as sphagnum moss, or a mixture of equal parts of sphagnum moss and sharp sand. Plant and mulch the bushes as recommended above. Despite this special planting, blueberries in alkaline areas will have pale yellowish green leaves with dark veins, a condition known as iron chlorosis, unless extra precautions are taken--ground water and even water from the garden hose may be alkaline enough to cause the chlorotic reaction. To counteract chlorosis, apply a solution of a chemical called iron chelate--1 tablespoon to a gallon of water for each plant--sprinkling it on the leaves and soil whenever the leaves lose their dark green color.

Fertilizer should be applied only if the leaves are uniformly pale, indicating a need for nourishment. Blueberries' roots are so fine they cannot assimilate strong fertilizers. The safest source of nutrients is cottonseed meal, which is nonburning and decays slowly. Use 1/4 pound around young plants and 1/2 pound around old ones; apply it very early in the spring, scattering it beneath the branches. However, ammonium sulfate is an excellent chemical fertilizer for old plants if cautiously applied: use a maximum of 1/4 pound for a plant 5 to 6 feet tall. Ordinary 10-10-10 fertilizer can also be used at the rate of 1 1/2 ounces for each year the plant has been in the garden, up to 8 ounces.

Blueberry varieties ripen over a two-month period in midsummer in most of the country, but the season's first berries ripen in May in Florida. To get sweet blueberries, allow the fruit to remain on the plants at least one week after they turn blue; unripe berries are sour. To pick only the ripe ones, cup the berry cluster in your hand and gently roll the darkest blue berries with your thumb. If they are ripe, they will drop easily into your hand; if any pressure is needed to loosen them, they are unripe and should be left on the bush. Pick at weekly or 10-day intervals.

Birds are the greatest threat to blueberry culture, and the only defense against them is to cover each plant with black plastic netting; clip the ends together beneath the plant with clothespins. Put the net on as the berries begin to turn pink, and remove it after the fruit have been picked.