Gardening Basics: Pears

Pear Essentials
By: National Gardening editors
Planning
• Choose fire blight-resistant varieties and rootstocks, especially in areas outside dry western regions.
• Most varieties will start to bear significant harvests after 5 to 6 years.
• Plant at least two different varieties for cross-pollination.
Preparation
• Choose a site with full sun, moderate fertility, and good air circulation and water drainage.
• Pears will do well in a wide range of soil types.
Planting
• Space standard-size trees 20 to 25 feet apart; space dwarf trees 12 to 15 feet apart.
Care
• Pears do best with a small amount of fertilizer early in the year. Heavy doses of nitrogen will make the tree more vulnerable to fire blight.
• Use spreaders to encourage horizontal branching and earlier fruiting spurs.
• See our article Fruit Pests and Diseases for controls of common pear pests such as pear psylla, codling moth, plum curculios, and fire blight.
Harvesting
• Don't let pears ripen on the tree. Harvest them when they reach a mature size but are still hard.
• Early pears will ripen at room temperature in a few days to a week. Storage varieties will keep 1 to 2 months or more in a cool (40F), dark place.
Pear Varieties
By: National Gardening editors
The extensive selection of high-quality pear varieties available that can't be found in grocery stores make pear trees well worth growing by home gardeners. Pears require less spraying than peaches, plums, or apples and are easy to train to fit small spaces in a yard. Unfortunately, pear trees can be affected by two serious problems. The insect pest the pear psylla can be difficult to control. And the bacterial disease fire blight has made larger-scale commercial pear growing difficult in many parts of the country. Because of fire blight, most of the United States pear crop now comes from northern California, Oregon, and Washington, where the predominantly dry climate discourages the spread of this disease. If you live outside of this region, you can still grow pears successfully by selecting blight-resistant varieties and rootstocks. With good planning and vigilance during the season, you can grow fresh, tender pears year after year with minimal use of chemical products.

Pear Varieties

Pears can usually be grown wherever apples are successful, though they are somewhat less resistant than apples to extremes of heat and cold. Pears, however, need less attention than apples in matters of pruning and insect control and are more tolerant of moist soil conditions. So if you have predominantly clay soil, pears will probably do better for you than apples on the same site. Compared to other tree fruits, pears are slower to start producing. Many apple varieties begin bearing in 3 to 4 years; with pears, the wait for good crops is longer. Standard types will take about 4 to 8 years to begin bearing; dwarfs, 4 to 6.

As a general rule, pears must be cross-pollinated to produce fruit, so plan to plant two varieties; most combinations of pear varieties will work except for 'Bartlett' and 'Seckel', which don't cross-pollinate well with each other. Out of nearly three thousand varieties, perhaps a hundred have good yields, flavor, texture, and keeping qualities. However, fewer than twenty are grown commercially. Thus, the home gardener has a wide choice of top-quality specialty pears. There are several pear varieties that offer effective resistance to fire blight, such as 'Moonglow', 'Magness', 'Maxine', 'Seckel',

and 'Kieffer'. In the South, plant resistant varieties such as 'Leconte' and 'Baldwin'.
Fireblight Disease on Pears
By: National Gardening editors
Fire blight, unlike most fruit tree diseases, is caused by a bacteria that can be spread from tree to tree by bees, aphids, pear psylla, and other insects. The bacteria mainly attack twigs and young shoots.

Fireblight Symptoms

Affected branches wither and turn black or brownish black, as if scorched. Most branch tips, once infected, wilt rapidly, taking on a shepherd's crook shape. The bacteria enter the tree through the blossoms or through lush, tender new growth. Once inside, they multiply rapidly and begin to work toward the roots. An orange-brown liquid will ooze from pustules on the tree, particularly on warm days. This liquid contains a great number of bacteria, which may be spread by rain or insects. The bacteria form a canker under the bark and survive there through the winter, infecting more trees the following year.

Pruning to Control Fireblight

Fire blight is a very serious disease in most parts of the country; it can wipe out all susceptible trees in an orchard in one season. It can be controlled, however. Fire blight is most damaging during bloom, when the blossoms become entry points for the bacteria. If you have a mini orchard -20 to 30 pear trees - it would pay to use an antibiotic spray or dust during bloom and shortly after to prevent the blight bacteria from reproducing. Fire blight spreads rapidly in periods of warm, humid weather, so check the trees carefully at such times for signs of wilting. Remove all suckers and cut off any infected branches before the bacteria attack the tree further. Using a sharp set of pruning shears, cut off the wilting branch at least 8 inches below the point of last visible wilt. After each cut, dip the shears in a solution of 1 part household bleach to 9 parts water to avoid transmitting bacteria from one branch to another. (When you are finished, wash and oil your tools to prevent damage from the bleach.) Discourage lush growth because it is very susceptible to fire blight damage. If possible, remove other plants that may serve as hosts for the disease, including wild apples, hawthorns, mountain ash, and cotoneaster hedges. Prune out fire blight cankers in the winter when trees are dormant. Leaves remaining on blighted branches in autumn can indicate trouble spots. If you prune before the sap starts to flow in the spring, you don't have to sterilize your tools after each cut.

Control Pests Too

Control aphids and pear psylla to prevent them from spreading the disease. The chief pest of pear trees in eastern and western (but not central) United States is the pear psylla. This reddish- brown insect rapidly develops resistance to chemical controls; it causes significant damage by spreading pear decline and fire blight and sucking out the plant sap. The insects emit a sticky substance called honeydew on which a black fungus grows. Yellow jackets may congregate around the black fungus, indicating pest activity. Control adults with dormant oil spray in the fall when they are most susceptible. A fall spraying is better than a spring spray because it will not affect many of the beneficial insects that are present in the trees in very early spring. If necessary use a dormant oil spray in the spring to inhibit egg-laying and to kill any active adults present. The adults begin to lay eggs when the temperature gets up to 70F, sometimes at slightly lower temperatures on a sunny day with no wind. You will have to use a 10-power magnifying glass to see the little yellow eggs at the base of the bud scales. As soon as you find any eggs, the first oil spray should go on. Spray again 7 days later. The insects don't seem to like laying eggs on this oily surface. Be sure to cover the tree thoroughly - until it's dripping. During the growing season use an insecticidal soap spray to keep pear psylla activity down.
Pear Care
By: National Gardening editors
Pears need soil with moderate fertility. Frosts during the bud and blossom period can damage the flowers and reduce yields significantly. Try to locate pears on a slope for better air drainage, or on the north side of a building to retard flowering. Space standard trees 20 to 25 feet apart, dwarf trees 12 to 15 feet apart.

Fertilizing Pears

Keep young trees weed-free, and water well during dry spells to help the roots get established quickly. Fertilize lightly in early spring of the second and succeeding years about 2 weeks before bloom. In moderately fertile soils, use ammonium nitrate at 1/8 pound or its equivalent per tree, multiplied by the number of years the tree has been set. Use less if you have highly fertile soil. If shoot growth on the tree is more than 12 inches in a season, use less fertilizer the following spring. If the leaves are pale green or yellowish in midsummer, add slightly more fertilizer the next year. Be careful applying fertilizer around your pear trees. Too much nitrogen promotes succulent growth, which allows fire blight disease bacteria to enter the tree's tender young shoots more easily.

Also, pears require several months to harden off in the fall. High nitrogen levels after mid-summer delay this hardening-off process. If your pear tree is located in a lawn area, cut back on turf fertilizer applications when you feed your lawn so as not to give your trees too much nitrogen.

Pear Pruning

Dwarf pears are often trained to a central leader. Semi-dwarf and standard-size trees also yield best when trained to a central leader, but they are usually trained to a modified leader because that form is easier to maintain with a larger tree. In an area prone to fire blight, you can prune your tree to multiple leaders. That way an infected leader can be removed while the others keep growing.

Pears are trickier to prune well than apples because all their branches grow nearly straight up. This growth habit promotes weak branches and dense foliage around the center of the tree, which encourages fire blight, fungus diseases, and pear psylla. Once you get the knack of pruning, the results will be worth the trouble. Prune regularly, though generally very lightly. Spreaders will help direct the tree's scaffold branches to a more outward, horizontal direction, and will encourage early development of fruiting spurs. Fortunately, pears are easier to train than most trees. Start in early summer of the first year. Toothpicks or clothespins can be used when branches are small; later, use wooden slats with the ends notched in a "V" to hold them in place. Sharp ends of spreaders can poke into the trunk and branch slightly, but won't hurt the tree. (An alternative practiced by some growers in the West is to hold branches down with a string tied to a clip in the ground). Pears bear their fruit mainly from terminal buds on short branches or spurs. Mature trees need only light pruning during the dormant season, mostly to thin out unfruitful, diseased, or crowded branches.

Avoid heading back cuts during dormant pruning since this will result in new, long, unfruitful shoots. If you have a variety that bears at an early age, such as 'Bosc' or 'Bartlett', remove fruit developing on the ends of thin fragile branches to keep the limbs from breaking.

Pollinating Pear

Pollination can be a problem with pears because bees are not partial to their blossoms; pear nectar contains less than 10 percent sugar, compared to nearly 50 percent in apple nectar, and pears often flower when it's too cold (below 55F) or wet for the bees to fly. To make matters worse, pear blossoms are fertile only for a short time. Pollination is most likely if the weather is warm during pear blossom time. If you're fortunate enough to live near an ocean coast or large lake, the cooling influence of the water in the spring promotes later blooming of pears and facilitates pollination. Ask other pear growers if pollination in your area is erratic from year to year; if so, you may need a beehive when your trees are coming into their bearing years for consistent fruit set. Move it to within 50 feet of your pear trees when blossoming starts. Even with a beehive, you may have occasional years of near-total crop failure owing to frosts or poor flying weather for the bees.
Codling Moth on Pears
By: National Gardening editors
The codling moth ("codling" is an old name for a tiny apple) is a key pear and apple pest. The first adults appear at the time blossom petals fall. The adult insects lay eggs on young fruit, twigs, and leaves.

Controlling Codling Moth

Trichogramma wasp parasites will attack codling moth eggs and should be released about 10 days after any spray application. As the eggs start to hatch, the young caterpillars feed on the leaves for a few days. This is a good time to spray the tree with Bacillus thuringiensis (B.t.), which kills various leaf-chewing caterpillars. The larvae don't feed heavily on the leaves so you might consider adding one or two tablespoons of skim milk powder as a feeding enhancer to your spray mixture. After feeding on the leaves briefly, the worms enter the pears and eat for about a month. Although the fruits will be ruined that year, you should try to intercept the larvae after they leave the pear and descend the trunk to reach the soil, where they will finish their life cycle. A strip of burlap about 6 inches wide and covered with Tangle Trap (a sticky, trapping substance) can be tightly wrapped around the trunk and stapled together to form a formidable and usually lethal barrier. Several turns of corrugated cardboard around the trunk will entice many of the surviving larvae to spin their cocoons in it, and after a while you can simply remove the cardboard from the tree and burn it. If there are two or more generations of codling moths in your area, use the burlap strip as a monitor of caterpillar activity and destroy the cardboard about a month after the first larvae are caught in the

Using Tangle Trap

Don't apply Tangle Trap directly to the tree because it will injure the bark. Woodpeckers, particularly the downy and the hairy, will eat up to half of the larvae that overwinter in the orchard area. Hang a block of suet in the trees to attract woodpeckers. Scrape off old, flaky bark by using chicken wire like a bath towel to deny winter cover to the larvae and make the birds' job that much easier.
Harvesting Pears
By: National Gardening editors
Pears should be harvested when they are mature, but still hard, and ripened off the tree for the best eating and canning quality. If you wait until the pears get ripe on the tree they'll be mushy inside within a day or two. The early varieties will take a few days to a week to ripen after harvest; later ripening varieties often require several weeks or more to reach best quality. Mature pears will be full size and the color of many varieties at this stage turns from green to light yellow. Generally, if you lift the fruit up it should break away easily from the stem. (The 'Bartlett' pear will need a slight twist to loosen it.) Pears grow larger and get softer all through the picking period.

Storing Pears

If you're going to keep some pears in cool storage for eating a month or two in the future, pick them when they are full size but still quite hard. Even though the skin is firm, handle them gently; they bruise easily. Pears that you will eat right away can be harvested later when the skin is a bit softer. Many varieties can be kept for a few weeks in a cool, dark place. For longer storage, pears need refrigeration at 32F to 40F. Bring them out to room temperature for a week or so before eating them.