Pruning Your Young Japanese Maple: A Guide for Healthy Growth

Acer Pruning: A Guide for Young Trees

Introduction

Japanese maples, particularly Acer palmatum varieties like ‘Garnet’, are prized for their stunning foliage, graceful form, and contribution to the overall aesthetic of a garden. However, to maintain their beauty and health, proper pruning is essential. This guide provides advice on pruning young Japanese maples, focusing on the specific needs of newly planted trees and addressing common concerns like intertwined leaders.

Pruning Newly Planted Japanese Maples

When you first plant your Japanese maple, it’s natural to be hesitant about pruning. After all, you want the tree to establish itself. However, a little bit of judicious pruning in the first few years can set the stage for a healthy and attractive tree.

• First Year: In the first year after planting, the primary focus should be on removing dead, diseased, or damaged branches. This is a standard practice for any newly planted tree. These issues are usually a result of the planting process, transport or pests and diseases. Removing these branches helps prevent the spread of disease and encourages the tree to focus its energy on healthy growth. Don’t worry about major shaping at this stage. Focus on the overall health of the tree.
• Second and Third Years: As your tree becomes established, you can begin to think about shaping it. Again, remove any dead, diseased, or damaged branches. You can also start to address any structural issues, such as crossing branches or branches that are rubbing against each other. If you have a tree with multiple leaders (the main stems of the tree), assess them. If they are too close together, you may need to remove one to promote a more open structure.

Addressing Intertwined Leaders

One of the common concerns with young Japanese maples is the presence of multiple leaders, especially if they are intertwined. Here’s how to approach this situation:

• Why It’s a Potential Problem: Intertwined leaders can cause several issues. They may rub against each other, leading to the damage of the bark. This can create entry points for disease and pests. The intertwined branches can also create a dense canopy, reducing airflow and sunlight penetration. This can increase the risk of fungal diseases.
• Assessing the Situation: Examine the intertwined leaders carefully. Consider the overall shape and balance of the tree. Which leader is dominant? Which one looks healthier? If both leaders are competing and you are unsure, observe for a season and see which leader seems to be growing more vigorously and shows a better form.
• Making a Decision: It’s often best to remove one of the leaders to avoid the problems mentioned above. The goal is to establish a single, strong leader. Choose the leader that has the most desirable form and is the healthiest. The best option is usually the most upright and central leader. Cut the other leader back to its point of origin, as close to the main trunk as possible. Make sure you do not leave any stubs.
• Stagger the Pruning: If you are unsure, you can stagger the pruning over a couple of years. Remove some of the less desirable growth each year. This will give the tree time to adjust to the change in structure.

General Pruning Tips for Japanese Maples

• Timing: The best time to prune Japanese maples is during the dormant season, typically in late winter or early spring (before the buds begin to swell). This minimizes sap loss and reduces the stress on the tree. However, you can remove dead, diseased, or damaged branches at any time of year.
• Tools: Use sharp, clean pruning tools to make clean cuts. This will help prevent the spread of disease. For smaller branches, use hand pruners or loppers. For larger branches, use a pruning saw.
• Technique: Make clean cuts just outside the branch collar (the swollen area where the branch joins the trunk). Avoid leaving stubs, which can be unsightly and can become entry points for disease. Do not prune more than 20% of the tree’s canopy in any single year.
• Shaping: Japanese maples naturally have an attractive shape, so the goal of pruning is often to enhance this natural form. Remove branches that detract from the tree’s overall shape, such as those that are growing inward or crossing each other.
• Thinning: Thinning the canopy can improve air circulation and sunlight penetration, which helps prevent fungal diseases and encourages healthy growth.

Specific Considerations for Acer palmatum dissectum ‘Garnet’

Acer palmatum dissectum ‘Garnet’ is a beautiful, weeping variety with finely dissected leaves that turn a vibrant red in the fall. Here are a few specific considerations for pruning this cultivar:

• Weeping Habit: This variety has a natural weeping habit. Your pruning should complement this natural form. Avoid pruning in a way that disrupts the weeping structure.
• Foliage: Be careful not to remove too much of the fine foliage. The leaves are the main attraction of this variety, so try to preserve the overall density of the canopy.
• Sunlight Exposure: Consider how much sunlight the tree receives. If the tree is in a partially shaded location, you may want to thin the canopy slightly to allow more sunlight to reach the inner branches.

Conclusion

Pruning your young Japanese maple is a rewarding process that helps ensure the health and beauty of your tree for years to come. By following these guidelines, you can address any concerns you have about your tree’s structure, such as intertwined leaders, and encourage healthy growth and a beautiful form. Remember to observe your tree, make careful decisions about pruning, and enjoy the process of nurturing your Japanese maple.