Effective Advice on How and When to Trim Arborvitae

man on a ladder trimming the top of an arborvitae tree

Arborvitae (genus Thuja) is a fast-growing ornamental tree. It is often used to create living privacy fences, with bottoms wider than the top. This evergreen is a genus of five species, but two are used the most in North American landscaping. They are Emerald Green (Thuja occidentalis “Smaragd”) and Pyramidal (Thuja occidentalis “Pyramidalis”).

Arborvitae trees need air circulation and sunlight on their lower branches for optimal health and growth. Pruning your arborvitae to remove dead, damaged, or diseased branches will help.

But when is the best time for pruning? And how do you trim overgrown arborvitae?

When Is the Best Time to Trim Arborvitae?

Generally speaking, the best time to trim your arborvitae is early spring, just before the growing season begins. Here in Rockford, IL, we recommend you trim your trees in March.

This is the best time for major pruning to maintain tree height and shape. Minor pruning of an errant or damaged branch can be fixed at any time of the year. A good rule of thumb is light trimming in the warmer months, and heavy trimming during the dormant season.

Help Your Arborvitae Grow Thicker

Proper pruning improves the health and growth of your evergreen hedgerow. It can even help prevent issues like needle blight. So how do you trim arborvitaes?

Before you bring out your hand pruning shears, pause and assess your trees. How old are they and what condition are they in? How much are you planning to remove? You will want to avoid cutting your shrubs until they have been established for at least a year (two years or more is even better). Pruning too much at a young age can cause stress and stunt the tree!

When growing arborvitae as a hedge or privacy fence, “top” them in the early spring. This will push more lateral growth, resulting in a thicker hedge. “Topping” is landscaper speak for shortening the tree. For example: if you have a 5-foot tall bush, we recommend you take 4-6 inches off of the top to encourage lateral growth.

Arborvitaes are multi-stemmed, and as such, they are prone to damage from snow and ice. The “topping” method of pruning can help protect your trees. When Emerald Green arborvitae are wider and sturdier it will help them handle the weight of snow and ice accumulation.

a line of arborvitae trees forming a hedge

How to Trim an Overgrown Arborvitae

How to trim arborvitae will depend on your vision for the outdoor space. Arborvitae grows quickly at the top. This can cause issues both visually (like blocking your garage lights or house number) and structurally. A good trim can solve these problems.

Don’t be overly eager with the lopping shears. Removing dead branches is one thing, but removing large sections of a live tree can be stressful to the plant. Aim to remove no more than a third of the shrub per season. Consistent trimmings over time are better than butchering your arborvitae in one go. Be sure to limit hard pruning to early spring while your plants are still dormant. The heat of mid-summer is no time to be making drastic changes!

Can you cut arborvitae to the ground? Yes, but we would not recommend it. Be aware that it may take some time to grow back and it may never return to its former glory. Arborvitaes typically do not do well with rejuvenation pruning as it will not send up a new central leader.

Easy Trimming Advice for All

Arborvitae thuja is a great addition to your landscape. They’re one of our favorite design pieces for timeless curb appeal with the added benefit of privacy. We hope you are now equipped to keep your arborvitae looking healthy and beautiful.

Are you looking to create the outdoor living space of your dreams? M2 Landscaping is ready to make your dreams a reality. Give us a call today or fill out our contact form to schedule your free consultation.