Arborvitae, which belong to the genus Thuja, are popular evergreen conifers that are often used for ornamental purposes. In addition to being ornamental trees, they are also efficient at creating living privacy screens.
They require regular pruning to maintain their shape and height, removing damaged branches. Understanding when and how to prune these plants can help in maintaining their health and growth.
When to Prune an Arborvitae?
Gardeners are often unsure when to prune an arborvitae. Many tend to prune them in early spring, along with their deciduous trees; however, this timing is not ideal for conifers. It is better to avoid pruning during the dormant season.
They can be pruned at any point during the growing season, but the most suitable period would be from late summer to early autumn. If not, they can also be pruned during late spring, after the new shoots have matured.
When it comes to young and fast-growing thujas, it is best to prune twice a year. To sum it up, it is best to avoid pruning during extremely hot summer days or the dormant period.
How to Prune an Arborvitae?
In addition to knowing when, it is equally important to know how to prune arborvitae correctly. Although arborvitae demand a fair amount of pruning, they generally only require shaping to maintain their appearance and remove damaged growth. Here are a few guidelines to help you understand how to prune an arborvitae.
Avoid Cutting Too Much
They are hardy plants, but their new growth does not emerge from old wood. Cutting branches back too far can lead to blank spots with no new growth. To prevent this, gardeners should stick to the last 10-20% of the branches. It is best to trim the terminal tips and avoid removing more than 25-35% of the tree's total foliage.
Cut at the Correct Location
During pruning, cuts should be made at the junctions of new shoots, while keeping the cuts in the green wood. To check this, you can make a small scratch in the bark and check if the wood underneath is green. It is best to avoid cutting beyond the green needles.
To maintain their height, cuts can be made above the point where the branch meets a shoot. For branches shooting beyond the outline of the foliage, trimming them inside the border will help in maintaining the shape.
Prune in Sections
It is best to work in sections, rather than cutting around the tree. There would be less possibility of mistakes if the gardener chooses to work on one side of the tree at a time, thereby avoiding uneven trimming.
Step Back and Assess Regularly
Throughout the process, it is important to step back and assess the progress. The goal is to create a uniform shape that allows light to reach the lower foliage. When pruning the hedge of an arborvitae, running a string line in front of or behind the plants can help ensure a straight or consistent form.
Additional Tips for Pruning an Arborvitae
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Pruning should never extend beyond the point where branches still carry green foliage, unless the goal is to completely remove the branch. In this case, gardeners can prune right back to the trunk.
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Once the arborvitae branch becomes bare, it will not produce new growth.
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It is also important to avoid rejuvenation pruning, a method where the plant is cut close to the soil level while anticipating that it will grow much stronger and healthier. If the plant is extremely damaged, it is best to replace it. While replacing, make sure to choose a new arborvitae that matches the size of the older arborvitae to maintain the balanced appearance of the hedge.
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The upper part of an arborvitae hedge tends to grow faster than the lower portion. Therefore, pruning more from the top helps ensure that adequate sunlight, water, and nutrients reach the lower branches. This also promotes even and healthy growth throughout the plant.
Right Tool for the Pruning
A hedge trimmer is one of the most effective tools for pruning an arborvitae. These trimmers are available in both electric and battery-powered models, with a range of blades and handle lengths to suit different needs.
For taller hedges, models with extended handles are better as they provide easier reach and better control. In addition, manual hedge shears can be helpful in maintaining the smaller section of the hedge.
Conclusion
Regular and careful pruning of an arborvitae keeps it healthy, well-shaped, and visually appealing. It is important to know the right time to prune, the proper technique of pruning, and the choice of suitable tools to ensure a successful pruning. Overall, consistent care and pruning contribute to the steady growth of these evergreen conifers.
