Watering

The first year following transplanting of the blueberry plant in the field or garden is critical. The young plant is very sensitive to drying out, over-watering, fertilizer level, and weed competition.

An inch of water per week through the growing season is usually considered essential for maximum growth and fruiting of blueberries. Water is especially critical just after setting the plants, through the first two growing seasons, and at the time of flowering and fruiting.

Water can be applied from an open hose, porous hose, by sprinklers, or by surface irrigation.

Since blueberries bear their fruit on new shoots produced during the previous growing season, it is essential to balance growth and fruit production with proper fertilization and pruning.

The purpose of fertilizing and pruning the plant during the first 3 to 4 years is to establish a number of well-spaced, stocky canes bearing many branch shoots with 6 to 12 flower buds each. During the plant's mature years, the cultural objectives are to keep the plant from getting too tall; to keep the canes branching freely; and to keep the plant producing a modest supply of new renewal canes.

Certain fertilizer salts, such as lime and chlorides, should be avoided in feeding blueberries. Don't fertilize blueberries at planting, but fertilize lightly 4 to 6 weeks later. Blueberries generally respond to nitrogen in the ammonium form, and at least once a year it is wise to apply a complete fertilizer (nitrogen-phosphorus-potassium) in a 1-1-1 or 1-2-1 ratio, such as 8-8-8 or 5-10-5. This applies especially to the East Coast. In Michigan a 2-1-1 fertilizer is preferred. For the home garden, azalea and camellia fertilizer mixes are satisfactory.

Top, spraying to control insects (note attire for protection against spray. Gloves also are a good idea.) Bottom, netting spread over frame will keep birds from eating your berries.

One ounce of complete fertilizer per year of plant age up to a maximum of 8 ounces per plant per year for mature plants is a good rule of thumb for fertilizing blueberries. During the first two years, the fertilizer is split and applied several times through the growing season.

From the third year on, apply the complete fertilizer just as the flower buds are breaking. Apply an ammonium nitrogen fertilizer about 6 weeks later. Occasionally, an additional application of nitrogen fertilizer is made in early summer if the plants are quite yellow after the fruit harvest. Bear in mind that blueberries are very sensitive to excess fertilizer.

Broadcast fertilizer evenly around the plant. Extra nitrogen should be added to mulched plantings to help decompose the mulch in early years of the planting, but the plant's age and vigor in relation to the quantity of fertilizer applied must be kept in mind.

Pruning

Blueberry plants need not be pruned. However, on unpruned plants the twig growth will get thinner, the branches will shade each other out, the fruit will be very small, and the plant will die sooner than expected. Hence, it is suggested that blueberries be pruned annually during the dormant season. This will lengthen bush life, produce strong new growth, space the bearing wood evenly for best light distribution, and reduce the crop so as to increase berry size and regulate ripening time.

Prune lightly in the first two years to remove low branches, overlapping branches, and flower buds.

From the third year on, remove old canes that are weak or being shaded. Cut back very vigorous upright shoots to force branching at a lower level. Prune out overlapping canes and branches. On the remaining canes, remove the short weak shoots and tip back long shoots to about 6 to 8 buds. Reduce very heavily branched canes by a third.

Select several renewal shoots around the plant and cut them back to 12 to 18 inches if they come from the ground, and 4 to 6 inches if they arise as a branch on an older cane.

Stem borers and leaf and stem spotting fungi may prove troublesome to young blueberry plants. On bearing-age plants, problems may be caused by leaf chewing insects, bud mites, stem and leaf fungi, and fruit worms. Your county Extension office can suggest appropriate controls for these problems, and recommend varieties resistant to some pests.

Many species of birds are especially fond of blueberries. The berries can be protected with a variety of cloth barriers, nets, or cages during fruiting.

Weekly harvesting of the fully colored and plumpest berries is necessary to get the maximum flavor and fruit-keeping quality. Many rabbiteye and several highbush varieties do not attain prime flavor until they have been fully colored on the plants 5 to 10 days.

Blueberry plants will live 25 to 30 years, with at least 10 to 15 prime bearing years. Mature plants in their prime can be expected to yield 6 to 8 pounds of fruit for highbush varieties and 12 to 15 pounds for rabbiteye varieties. Yields as high as 24 pounds for highbush and 50 pounds for rabbiteye have been reported, but these are rare.