Ask the Arborist: When should I prune my apple trees?

Welcome to the latest edition of Ask the Arborist.  In this column, we aim to answer your tree and shrub care questions, and address current conditions we are seeing around town. Our goal is to help you learn more about how to care for the trees and shrubs on your property, and recognize any potential problems.

When should I prune my apple trees?

There are many apple tree varieties that thrive in Colorado. If you have apple trees on your property, it’s important to understand how to properly care for them to promote healthy growth and prevent pests and disease.

One of the common mistakes we see homeowners make is trimming their fruiting and flowering trees while the fruit and leaves are present. This can create a number of problems including slowed fruit ripening, unhealthy growth, and undue stress that can make your tree vulnerable to pests and disease.

Fruit trees, including apple, crabapple and pear, need to be fully dormant before pruning. The best time to prune apple trees is right now, in the dead of winter. Trees sustain less damage and have more time to heal when they are trimmed during winter. There are many benefits of winter trimming including less stress and decreased risk of infection from diseases such as fire blight. Too many beautiful fruit trees become the victims of blight and other diseases from poorly timed trimmings.

What is fire blight?

Fire blight is a destructive bacterial disease that causes a scorched appearance on infected leaves. Apples and crabapples affected by fire blight may also present with dead branches and dried fruit. A reddish ooze can sometimes be seen coming from cankers on the trunk and branches.

As soon as spring temperatures warm, the disease starts its rapid multiplication process. Enormous amounts of bacteria are secreted out the infected tree’s bark pores and other openings.

Insects, such as beetles, aphids, ants, bees, and others, are drawn to the fire blight’s secretion, which is a type of sticky gum. These insects transfer the sticky ooze to other tree’s blossoms over time and the fire blight continues spreading.

What can I do?

Fire blight can spread quickly and attract unwanted pests, so it’s important to take action and consult with one of our certified arborists to establish an ongoing treatment plan. Proper trimming must take place at the appropriate time of year to remove damaged branches and avoid the spread of infection.

A preventative maintenance plan is also important to support the long-term health of your tree. Annual fertilization will help maintain healthy growth and give your trees and shrubs the nutrients they need to flourish. Our certified arborists can work with you to identify specific problems and determine the best course of action.

If you have concerns, it’s important to act quickly. The window for apple pruning closes in March. Don’t wait to schedule your free consultation. Contact us today!