How to grow pear trees in eastern Idaho

As one of the hardier fruit trees, gardeners can grow pear trees successfully in eastern Idaho. Growing pear trees takes commitment to year-round care and special consideration should be given to the location, variety, and care of the trees prior to planting.

The ideal location is one without frost pockets. A gentle slope with good air drainage will keep frost from settling on your tender shoots. Plant trees three-quarters of the way down the hill to allow freezing air to drain down the hill. Soil should be deep and well-drained to avoid root and crown diseases. Light is important, plant trees away from buildings or other trees that could shade them. Pruning can help light penetrate the inner leaves, improving flower production and fruit set throughout the tree.

Pears are less hardy than apples and can suffer freezing injury as they bloom prior to apples. The buds and wood are typically hardy to about -25°F. Particular care should be taken to protect pear trees when temperatures drop like has happened this past week. One protection you can employ is during the fall wrap tree trunks with white plastic tree guards. These tree guards help reduce sun scald on fruit trees by reflecting light and blocking freezing winds.

There are two basic types of pears, Standard (European) Pears and Asian Pears. Pears require cross-pollination, so plant two cultivars close together. Both Asian pears and European pears are available in Idaho, but because of European pears bloom later, they are better adapted to eastern Idaho.

Irrigation

Establishing new trees through proper irrigation is critical. When you first plant pear trees make sure you give them 2-3 gallons of water a couple times a week. Check the soil to ensure it is moist to 6-8 inches near the tree. In following years, trees will need 1-3 inches of water per week during the summer months and into the fall. A deep soak with less frequent irrigations allows water to penetrate throughout the entire root zone. A deep irrigation that wets the soil to a depth of 18-24 inches every 7-10 days is preferred. Avoid using sprinklers to keep the tree canopy dry, prevent foliar diseases, and minimize fruit exposure to untreated irrigation water.

Fertilization

Trees less than 3 years old should average 12-15 inches of growth a year. If you are getting more than 24 inches of growth, reduce the amount of nitrogen fertilizer you apply. A rule of thumb for nitrogen fertilizer is 1/10th of a pound per inch diameter (measured 12 inches above the ground). If I had a 4-inch diameter tree, I would apply 4/10th of a pound of nitrogen fertilizer a year. Divide the application so that one application is made in early spring and the other mid-May. Do not fertilize after mid-July. Trees bearing fruit should grow about 12 inches a year. Utilize soil tests to determine other nutrient requirements.

Pruning

Begin pruning and training pear trees at planting. For unbranched trees, make a single cut 3 feet above the soil line. This encourages side branches that will become permanent scaffold branches. In the early spring following the first year, select the uppermost branch as the central leader. Keep the best 4-5 lateral branches below that as scaffolds. When you prune young branches in this manner, you develop a strong, well-balanced framework of scaffold branches.

Pruning should be as light as possible on fruit bearing trees. Pruning cuts should be restricted to branches that severely rub each other and to water sprouts as they appear. Only head back terminals to a lateral should be done as the tree becomes too tall.

Dormant pruning should take place mid-winter. Diseases are less likely to spread at this time. If pruning does take place during the growing season, make sure to properly sanitize your pruning tools with 10% Clorox, 70% ethanol, 70% isopropanol, or Pine-Sol. If used as a soak, change solutions every 2-3 hours.

Problems

Growing pears does not come without its problems. Pears are very susceptible to Fire Blight, a bacterial disease that infects plant tissues resulting in dead, black tissue. Fire blight is spread through the blossoms and succulent new shoots. Common vectors include ants, flies, and wasps. Although bees do not feed on bacterial ooze, they can visit infected flowers and spread bacteria to uninfected flowers.

When detected, remove all tissue at least 10-15 inches past any visible discoloration. Sanitize tools between each cut. In the fall, immediately after harvest, or during the dormant season inspect the trees and remove all infections missed earlier. Cut 4-6 inches beyond discoloration now. More information on control of Fire blight is available here. Search for Pear Fire blight under the plant disease section.

Other problems include crown and root rot. Good water drainage and proper irrigation are the most important factors in preventing these problems. Codling Moth and Pear Psylla are the most important insect pests to be aware of. For control of codling moths, a mixture of cultural practices and accurately timed insecticide sprays are key. The best control for Pear Psylla is achieved with a dormant oil spray before leaves appear in spring.