"Truncating Arborvitae: Expert Tips to Reduce Height Without Damaging Your Evergreen"

Controlling the Height of Your Arborvitae: A Comprehensive Guide

Arborvitae, a popular choice for privacy screens and hedges, can grow quite tall, sometimes outgrowing their intended space. If you're wondering how to reduce the height of your arborvitae, you're in the right place. In this guide, we'll explore various methods to control the height of these versatile evergreens, ensuring they remain a beautiful and manageable addition to your landscape.

Understanding Arborvitae Growth

Before we dive into height reduction techniques, it's essential to understand how arborvitae grow. Most varieties grow at a moderate rate, adding about 24 inches to their height each year. Their growth can be categorized into two main types: upright and spreading. Upright varieties, like the Green Giant, grow tall and narrow, while spreading varieties, such as the Emerald Green, have a broader, more rounded shape. Knowing your arborvitae's growth habit will help you choose the best method for controlling its height.

Choosing the Right Variety

If you're planning to plant new arborvitae, consider choosing a dwarf variety. These compact growers stay smaller than their standard counterparts, making them an excellent choice for smaller spaces. Some popular dwarf varieties include the 'Juniperus horizontalis 'Blue Star' and the 'Thuja occidentalis 'Emerald Green'.

Pruning Techniques for Height Reduction

Pruning is the most common method for controlling the height of your arborvitae. It's essential to prune at the right time and use the correct technique to maintain your arborvitae's health and shape.

Timing Your Pruning

Arborvitae are best pruned in late winter or early spring, just before new growth begins. Pruning at this time allows the plant to heal quickly and encourages new growth. Avoid pruning in fall, as it can leave the plant vulnerable to pests and diseases during the winter months.

Shearing vs. Selective Pruning

There are two main pruning techniques for arborvitae: shearing and selective pruning.

• Shearing involves cutting back the entire plant to a uniform height and shape. This technique is best for formal hedges and screens and works well on upright varieties. To shear your arborvitae, use handheld hedge shears or a hedge trimmer, and cut back the new growth by about one-third.
• Selective pruning involves removing individual branches to control the plant's size and shape. This technique is ideal for maintaining the plant's natural form and can be used on both upright and spreading varieties. To selectively prune your arborvitae, look for branches growing in the wrong direction or those that are damaged or diseased. Cut these branches back to the point where they meet another branch or the main trunk.

Topping: A Word of Caution

Topping, or cutting back the main leaders to reduce height, is not recommended for arborvitae. This practice can cause the plant to produce weak, water sprouts, leading to an unsightly, open growth habit. It can also make the plant more susceptible to pests and diseases.

Other Methods for Controlling Arborvitae Height

While pruning is the most effective method for controlling arborvitae height, there are other techniques you can use to keep your plants in check.

Planting in Containers

If you want to grow arborvitae in a small space, consider planting them in containers. This method allows you to control the plant's size by limiting its root growth. Choose a container that is slightly larger than the plant's root ball and use a well-draining potting mix. Repot the plant every few years to maintain its health and prevent it from becoming root-bound.

Using Growth Regulators

Growth regulators, such as paclobutrazol, can be applied to arborvitae to slow their growth rate. These chemicals work by inhibiting the plant's hormonal system, preventing it from producing new growth. While growth regulators can be effective, they should be used sparingly, as they can also have negative side effects, such as discoloration and reduced plant vigor.

Installing Growth Barriers

For upright varieties, you can install growth barriers, such as metal or plastic stakes, to prevent the plant from growing taller than desired. These barriers should be installed when the plant is young, and they should be checked regularly to ensure they are still effective.

Maintaining a Healthy Arborvitae

Maintaining a healthy arborvitae is essential for controlling its height and preventing pests and diseases. Provide your plants with well-draining soil, regular watering, and adequate sunlight. Fertilize your arborvitae in early spring with a balanced, slow-release fertilizer, and mulch around the base of the plant to retain moisture and suppress weeds.

By understanding your arborvitae's growth habits and using the appropriate techniques, you can control the height of these versatile evergreens and create a beautiful, well-maintained landscape. Whether you choose to prune, plant in containers, or use growth regulators, there are numerous methods for keeping your arborvitae at the perfect height for your space.