By: National Gardening Association 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.
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.
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.