How to Prune a Crabapple Tree

Pruning a crabapple tree is crucial to maintain its health, shape, and beauty. With proper pruning techniques, you can encourage better fruit production, improve air circulation, and prevent diseases like apple scab. In the video above, This Old House landscape contractor Roger Cook demonstrates the correct methods for pruning a crabapple tree, saving a neglected specimen in the process. Here, we’ll recap these methods and provide some additional tips for maintaining fruit tree health.

Why You Should Prune Crabapple Trees

When done correctly, pruning a fruit tree can significantly improve its overall health, appearance, and longevity. Regulating the tree’s growth through pruning can also prevent it from becoming too dense, which often leads to poor airflow and sunlight exposure. This can ultimately reduce fruit quality and increase vulnerability to diseases.

When to Prune Crabapple Trees

The best time to prune is during the tree’s dormant period, typically in late winter or early spring before new growth begins. This timing allows the tree to heal quickly and reduces the risk of disease transmission. You’ll also be able to see the branches since they’re bare of foliage.

Tools and Safety Equipment for Pruning a Crabapple Tree

Before you begin pruning your crabapple tree, gather the necessary tools and safety equipment. 

Essential Pruning Tools

To prune your crabapple tree effectively, you’ll need the following tools.

• Bypass pruners
• Leaf rake
• Pole saw
• Pruning saw

Safety Equipment

Using proper safety equipment ensures that you’re protected from falling branches and sawdust, and it helps to maintain a firm grip on tools even when working at awkward angles. Be sure to use:

• Hard hat
• Nonslip shoes
• Safety glasses
• Sturdy gloves

Crabapple Tree Pruning Techniques

In the video, Cook demonstrates the correct methods for removing branches safely and effectively. These techniques help in preventing damage to the tree and encourage healthy growth.

The Three-Cut Method

You can often clip smaller branches and suckers with handheld bypass pruners. For larger branches, Cook recommends using the three-cut method to prevent bark tearing:

1. First cut: Make an undercut about a foot from the trunk, cutting one-third of the way through the branch.
2. Second cut: Make a second cut from the top, about half an inch beyond the undercut, until the branch falls away.
3. Final cut: Make the final cut just outside the branch collar, where the tree will heal properly.

This method ensures the weight of the branch doesn’t tear the bark from the trunk as it falls, allowing the tree to heal well and maintain its health. It also preserves the branch collar, preventing cavities from forming in the trunk. 

Removing Dead and Diseased Branches

Start by removing any dead, diseased, or damaged branches. These can be identified by their lack of leaves, discoloration, or visible damage. Removing these branches helps prevent the spread of disease and improves the tree’s overall health. Dead branches not only detract from the tree’s appearance but also can harbor pests and diseases, which may spread to healthy parts of the tree. 

If you suspect your tree may be infected, sterilize your pruning tools before and after making clean cuts close to the branch collar. First wipe any debris or sap off the blade, and then use one of these methods to sterilize it.

• Alcohol: You can use 70% isopropyl (rubbing) alcohol or ethanol straight from the bottle without needing to dilute it. Dip the blade in the alcohol or dampen a clean cloth with it and wipe the blade down.
• Bleach: If you want to use bleach, you must dilute it. Mix 1 part bleach with 9 parts water in a bucket, soak the blade for at least 10 minutes, and rinse the blade with clean water. Use bleach solutions within two hours of mixing and take care to protect your skin and clothing.
• Household disinfectants: Surface wipes, cleaners, and sprays are effective at killing bacteria on household items, though their effectiveness against plant pathogens hasn’t specifically been tested. They may be fine, but alcohol and bleach are the preferred methods.

Pro tip: If your crabapple tree has fire blight, use bleach instead of alcohol or other household disinfectants, which tend to be ineffective against this particular disease.

Thinning for Better Air Circulation

To encourage better air circulation and reduce the risk of diseases like apple scab, thin out some of the vertical branches. This process also allows more sunlight to reach the inner parts of the tree, promoting better growth and fruit production.

When thinning, focus on removing branches that crisscross or those that grow inward toward the center of the tree. Better air circulation helps in drying leaves quicker, thereby reducing the likelihood of fungal infections.

Shaping Your Crabapple Tree

Learning which healthy branches to prune is as much an art as a science, but keep in mind that the goal is to create a balanced, open structure that allows for good air circulation and sunlight penetration.

Encouraging Horizontal Growth

Horizontal branches are generally more productive and stronger than vertical ones. When pruning, aim to keep the tree open and balanced, promoting a structure that can support the tree’s weight and withstand environmental stressors. To shape your crabapple tree effectively:

• Prune to maintain a balanced, rounded shape
• Remove vertical branches that compete with the main leader
• Trim back branches that cross or rub against each other
• Avoid over-pruning, which can stress the tree

Dealing with Suckers

Suckers are small, vertical branches that grow from the base of the tree or along main branches. Use pruning shears or a pole saw to cut suckers as close to their point of origin as possible. Regularly removing suckers encourages the tree to allocate its energy and nutrients to the primary branches and fruit production rather than unnecessary growth.

Caring for Your Crabapple Tree After Pruning

After pruning, your crabapple tree will need some extra care to heal and adjust to the pruning stress.

Removing Infected Leaves

After pruning, rake up and remove all fallen leaves and twigs from around the tree. Diseased leaves can harbor fungal spores and other pathogens that can reinfect the tree in the following growing season. In addition, keeping the area clean reduces the chance of pests establishing a habitat near your tree. Dispose of infected leaves away from the tree to prevent the spread of disease.

Watering and Fertilizing

Water your crabapple tree deeply after pruning, especially if you’ve removed a significant amount of branches. This helps reduce stress on the tree. Apply a balanced, slow-release fertilizer in early spring to support new growth.

Deep watering provides essential moisture to the roots, helping the tree recover from the loss of branches. Fertilizing at the right time encourages healthy new growth and ensures the tree has the nutrients it needs.

Monitoring for New Growth

Keep an eye on your tree in the weeks following pruning. Look for signs of new growth and watch for any potential issues, such as pest infestations or symptoms of common crabapple diseases like apple scab. Early detection and treatment can prevent more serious problems from developing.

Additional Tips for Successful Pruning

Here are some extra tips for pro-level pruning:

• Plan your cuts: Before making any cuts, visualize the tree’s final shape and plan accordingly. This strategic approach prevents unnecessary cuts and helps achieve a balanced structure.
• Use sharp tools: Dull blades tear rather than cut, which puts more stress on the tree and extends healing time.
• Stay consistent: Regular modest pruning is better than infrequent, heavy pruning. Consistency helps the tree maintain a steady growth pattern and reduces stress.
• Clean your tools: Even if you don’t need to sterilize, clean tools of dirt, sap, and debris before putting them away and they’ll be ready to use next time.

Pro tip: If your tree is very overgrown and neglected, don’t try to shape it too heavily all at once. Penn State’s agricultural experts recommend “renovating” the tree over a period of about three years. Each pruning season, remove the dead or diseased branches, but don’t clip back more than about one-third of the healthy branches. Luckily, apple trees tend to respond well to this renovation process.