Knowing how to trim arborvitae shrubs is key to keeping these popular evergreens healthy and looking their best. This easy step-by-step guide will walk you through the entire process, from choosing the right tools to making the perfect cuts.
Trimming isn’t as scary as it seems. With a little know-how, you can shape your shrubs, control their size, and encourage lush, dense growth. Let’s get started with everything you need to know.
How to Trim Arborvitae Shrubs
This main section covers the core principles. Following these rules will ensure your arborvitae thrives after its trim.
Why Trimming Your Arborvitae is Important
Trimming is not just about looks. Regular, light trimming promotes a thicker growth habit. It allows sunlight to reach the inner branches, preventing them from becoming brown and sparse.
It also helps maintain a manageable size. This prevents the shrub from outgrowing its space and reduces stress on the branches, which can lead to splitting under heavy snow or wind.
The Best Time of Year to Trim
Timing is crucial for the health of your plant. The ideal window is in late spring or early summer, just after new growth has emerged. This gives the shrub time to recover and harden off new growth before winter.
You can do a very light tidy-up in late summer if needed. Avoid heavy trimming in fall, as new, tender growth prompted by cutting won’t have time to harden before frost arrives.
Essential Tools You’ll Need
Using the right tools makes the job easier and prevents damage. Here’s what to gather:
- Hand Pruners (Bypass Style): For precise cuts on small branches, up to about 1/2 inch thick.
- Hedge Shears (Manual or Electric): For shaping and trimming larger areas of soft, new growth. Electric shears save time on big jobs.
- Loppers: For cutting older, thicker branches that are up to about 2 inches in diameter.
- Safety Gear: Always wear safety glasses and sturdy gloves to protect your eyes and hands.
Make sure all your tools are clean and sharp. Dirty, dull blades can crush stems and spread disease between plants.
Understanding Arborvitae Growth
Arborvitae generally do not produce new growth from old, bare wood. This is the most important concept to grasp. If you cut back to far into the brown, inner part of the branch, it will not regreen.
Always leave some green foliage on every branch you cut. Your goal is to trim the green, leafy part, not to cut into the leafless wood underneath the outer canopy.
The Step-by-Step Trimming Process
Now, let’s walk through the actual trimming process step by step. Take your time and work slowly for the best results.
Step 1: Inspect and Plan
Start by walking around your arborvitae. Look for dead, damaged, or diseased branches—these will be your first priority. Then, decide on the shape and size you want to achieve.
It’s helpful to visualize a slightly tapered shape, wider at the bottom than the top. This allows sunlight to reach the lower branches and promotes even growth.
Step 2: Remove Problem Branches First
Using your hand pruners or loppers, remove any dead or broken branches. Cut them back to the main trunk or to a healthy lateral branch. This cleans up the plant and prevents potential entry points for pests.
Dispose of these branches seperately from your garden compost to avoid spreading any issues.
Step 3: Start Light Shaping
Begin with your hand pruners to make selective cuts. Look for branches that are sticking out awkwardly or are longer than the rest. Follow the branch back into the plant and make your cut just above a side shoot or set of leaves.
This method hides the cut and encourages branching at that point, making the shrub fuller. Don’t just shear off the top without this selective pruning first.
Step 4: Use Hedge Shears for Fine-Tuning
After the selective pruning, you can use hedge shears to even out the shape. Work in smooth, sweeping motions, following the natural contour of the shrub. Step back frequently to check your progress from a distance.
Remember the golden rule: never remove more than one-third of the total green growth in a single season. It’s better to trim a little now and a little later than to cut to much at once.
Step 5: Clean Up and Dispose
Thoroughly rake up and remove all clippings from around the base of the shrub. This improves air circulation and denies hiding places for insects and rodents.
You can chip the trimmings for mulch, but ensure they are healthy first. Brown, dead material should go in the yard waste bin.
Common Mistakes to Avoid
Even with good intentions, it’s easy to make errors. Here are the big ones to steer clear of:
- Topping the Plant: Lopping off the entire top to reduce height often ruins its natural shape and leads to weak, ugly regrowth.
- Cutting Into Old Wood: As mentioned, cutting back to far where there are no green needles will leave permanent bare spots.
- Creating a “Hard Edge”: Shearing only the outside creates a dense outer shell that blocks light and air, causing inner branches to die off.
- Trimming at the Wrong Time: Late-season trimming stimulates vulnerable new growth that winter cold will damage.
Aftercare Tips for Healthy Regrowth
Your job isn’t quite done after trimming. A little aftercare helps your arborvitae bounce back quickly.
Water the shrub deeply if the weather is dry. This reduces stress and supports new growth. You can also apply a light layer of compost around the base (keeping it away from the trunk) to provide slow-release nutrients.
Avoid using high-nitrogen fertilizer right after trimming, as this can force to much tender growth. The plants natural recovery process is usually sufficient.
FAQ: Your Arborvitae Trimming Questions Answered
Can you cut the top off an arborvitae?
It’s not recommended. Arborvitae rely on their central leader (the main top branch) for structure. Cutting it off can result in multiple weak tops and an unnatural shape. For height control, lightly tip-prune the new growth each year instead.
How much can you trim off an arborvitae?
As a safe rule, never remove more than one-third of the live foliage in a single year. If a shrub is severely overgrown, plan to reduce it over two or three seasons to avoid shocking the plant.
My arborvitae has a big brown spot. Can I trim it out?
You can trim out dead brown branches, but if the brown area is within the canopy, the wood is likely dead and won’t regreen. Prune back to healthy green growth, but be prepared that a hole may remain. Sometimes, neighboring branches will gradually fill in the gap.
What is the difference between pruning and trimming arborvitae?
Trimming typically refers to light cutting for shaping and maintaining size, often with sheers. Pruning is a more precise practice using hand tools to remove specific branches for plant health, structure, and to thin out dense growth. Both techniques are usefull for arborvitae care.
Is it okay to trim arborvitae in the fall?
It’s best to avoid it. Fall trimming can stimulate new growth that won’t harden off before winter, leading to frost damage. Stick to the late spring or early summer schedule for any significant cutting.
With the right timing, tools, and technique, trimming your arborvitae is a straightforward task. Remember to work slowly, cut conservatively, and always respect the plants growth habit. Your efforts will be rewarded with dense, vibrant, and beautifully shaped shrubs that enhance your landscape for years to come. If your ever unsure, making less cuts is always safer than making to many.