Reclaim Your Garden: A Comprehensive Guide to Trimming Overgrown Boxwoods

Boxwoods, with their dense, evergreen foliage, are a classic choice for adding structure and formality to gardens. They’re versatile, used for hedges, topiaries, or standalone shrubs. However, like any plant, boxwoods can become overgrown if left untended. An overgrown boxwood loses its shape, becomes less dense, and can even suffer from reduced air circulation, making it more susceptible to pests and diseases. This comprehensive guide will provide you with the knowledge and step-by-step instructions to confidently trim your overgrown boxwoods back to their former glory, revitalizing your garden and ensuring the long-term health of your shrubs.

Why Trim Boxwoods?

Before diving into the how-to, let’s understand the ‘why.’ Trimming boxwoods offers several benefits:

* **Shape and Aesthetics:** Regular trimming maintains the desired shape, whether it’s a formal hedge, a rounded shrub, or an intricate topiary. Overgrown boxwoods become shapeless and lose their visual appeal.
* **Density and Growth:** Pruning encourages denser growth. By removing outer growth, you stimulate new shoots from within the plant, creating a fuller, more compact appearance.
* **Air Circulation and Sunlight:** Dense, overgrown boxwoods can restrict air circulation and sunlight penetration, creating a damp, shaded environment that is ideal for fungal diseases and pests like boxwood blight and psyllids. Trimming opens up the plant, improving air flow and light exposure.
* **Plant Health:** Removing dead, diseased, or damaged branches prevents further spread of disease and promotes overall plant health.
* **Rejuvenation:** Overgrown boxwoods can become leggy with sparse foliage in the interior. Aggressive pruning can rejuvenate the plant, encouraging new growth from the base and interior.

When to Trim Boxwoods

The best time to trim boxwoods depends on your climate and the type of pruning you’re planning.

* **Light Trimming (Maintenance):** The ideal time for light trimming is **late spring or early summer**, after the first flush of new growth has hardened off. This allows the new growth to mature before the winter months. A second light trim can be done in **late summer** to maintain shape.
* **Heavy Pruning (Rejuvenation):** If your boxwood is severely overgrown and requires significant pruning, the best time is **late winter or early spring**, before new growth begins. This allows the plant to recover during the growing season. Avoid heavy pruning in the fall, as new growth may not have time to harden off before winter, making it susceptible to frost damage.

**Important Note:** Avoid trimming boxwoods during periods of extreme heat or drought, as this can stress the plants. Also, avoid trimming in late fall in colder climates.

Tools You’ll Need

Having the right tools is essential for efficient and effective boxwood trimming. Here’s a list of recommended tools:

* **Hand Pruners (Bypass Pruners):** For small, individual branches up to ½ inch in diameter. Bypass pruners make clean cuts without crushing the stem.
* **Hedge Shears:** For shaping and trimming hedges or creating a smooth, uniform surface. Both manual and powered hedge shears are available. Choose the type that best suits the size of your boxwoods and your physical capabilities. Manual shears offer more control, while powered shears are faster for larger hedges.
* **Loppers:** For thicker branches, up to 1 ½ inches in diameter. Loppers provide extra leverage for cutting through larger branches.
* **Pruning Saw:** For branches larger than 1 ½ inches in diameter. A pruning saw has coarser teeth than a regular saw and is designed for cutting live wood.
* **Gloves:** To protect your hands from thorns and scratches.
* **Eye Protection:** Safety glasses or goggles to protect your eyes from flying debris.
* **Tarp or Drop Cloth:** To collect trimmings for easy cleanup.
* **Measuring Tape (Optional):** For ensuring uniform height and width when trimming hedges.
* **String Line (Optional):** To guide straight cuts when trimming hedges.
* **Ladder or Step Stool (Optional):** For reaching higher areas of larger boxwoods.
* **Disinfectant:** Rubbing alcohol or a bleach solution (1 part bleach to 9 parts water) to disinfect pruning tools between cuts, especially when pruning diseased plants. This prevents the spread of disease.

Step-by-Step Guide to Trimming Overgrown Boxwoods

Here’s a detailed step-by-step guide to trimming overgrown boxwoods. The approach will vary slightly depending on whether you’re doing light maintenance trimming or a more substantial rejuvenation pruning.

**Step 1: Assess the Boxwood and Plan Your Approach**

* **Evaluate the Overall Shape:** Take a step back and observe the boxwood’s shape and size. Identify areas that are overgrown, uneven, or lacking density. Determine the desired final shape you want to achieve.
* **Identify Dead, Diseased, or Damaged Branches:** Look for branches that are brown, brittle, or showing signs of disease. These branches should be removed first.
* **Consider the Plant’s Health:** Assess the overall health of the boxwood. If it’s severely stressed or weakened, avoid heavy pruning. Instead, focus on improving its health through proper watering, fertilization, and pest control before attempting significant trimming.
* **Decide on the Type of Pruning:** Determine whether you need light maintenance trimming to maintain shape or a more aggressive rejuvenation pruning to revitalize an overgrown plant. This decision will influence the amount of foliage you remove.

**Step 2: Prepare Your Tools and Workspace**

* **Gather Your Tools:** Collect all the necessary tools listed above. Make sure they are clean and in good working order. Sharpen your pruning tools for clean, precise cuts.
* **Disinfect Your Tools:** Disinfect your pruning tools with rubbing alcohol or a bleach solution to prevent the spread of disease.
* **Lay Down a Tarp or Drop Cloth:** Place a tarp or drop cloth around the base of the boxwood to collect trimmings and make cleanup easier.
* **Wear Protective Gear:** Put on gloves and eye protection to protect your hands and eyes.

**Step 3: Remove Dead, Diseased, and Damaged Branches**

* **Start with the Obvious:** Begin by removing any dead, diseased, or damaged branches. These branches are not contributing to the plant’s health and should be removed immediately.
* **Cut Back to Healthy Wood:** When removing a diseased branch, cut back to healthy wood, making sure to disinfect your pruning tools between cuts to prevent the spread of disease.
* **Make Clean Cuts:** Use sharp pruning tools to make clean, precise cuts. Avoid tearing or crushing the bark, as this can create an entry point for diseases.
* **Cut at a 45-Degree Angle:** Cut branches at a 45-degree angle, just above a healthy bud or branch junction. This encourages new growth in the desired direction.

**Step 4: Thin Out the Interior (For Overgrown Boxwoods)**

* **Improve Air Circulation and Sunlight:** Thinning out the interior of an overgrown boxwood is crucial for improving air circulation and sunlight penetration. This helps to prevent fungal diseases and encourages new growth from within the plant.
* **Remove Crossing or Rubbing Branches:** Identify branches that are crossing or rubbing against each other. These branches can create wounds that are susceptible to disease. Remove one of the branches to prevent further damage.
* **Remove Weak or Spindly Branches:** Remove any weak or spindly branches that are not contributing to the overall structure of the plant.
* **Cut Back to a Main Branch or Bud:** When thinning out the interior, cut branches back to a main branch or bud, rather than leaving stubs. This encourages new growth from the remaining branch.
* **Avoid Removing More Than One-Third of the Plant’s Mass:** When thinning out the interior, avoid removing more than one-third of the plant’s total mass at one time. This can stress the plant and make it more susceptible to disease. If the boxwood is severely overgrown, it may be necessary to prune it in stages over several years.

**Step 5: Shape the Exterior (For Both Maintenance and Rejuvenation)**

* **Determine Your Desired Shape:** Decide on the desired shape for your boxwood. Common shapes include rounded shrubs, formal hedges, and topiaries.
* **Start at the Top and Work Down:** Begin shaping the boxwood at the top and work your way down. This allows you to see the overall shape as you progress and make adjustments as needed.
* **Use Hedge Shears for Uniform Surfaces:** Use hedge shears to create smooth, uniform surfaces, especially when trimming hedges. Hold the shears at a consistent angle to ensure an even cut.
* **Use Hand Pruners for Individual Branches:** Use hand pruners to refine the shape and remove any stray branches. This allows for more precise control than hedge shears.
* **Maintain a Wider Base Than Top:** When shaping boxwoods, it’s important to maintain a wider base than top. This allows sunlight to reach the lower branches and prevents the plant from becoming top-heavy.
* **Shear Sparingly:** Avoid shearing too deeply into the foliage, as this can create bare spots and weaken the plant. Instead, shear lightly and frequently to maintain the desired shape.
* **Step Back and Evaluate:** Periodically step back and evaluate the shape of the boxwood. This allows you to see the overall progress and make adjustments as needed.
* **Use a String Line for Straight Hedges:** When trimming a hedge, use a string line as a guide to ensure a straight, even cut. Attach the string line to stakes at either end of the hedge and adjust the height as needed.

**Step 6: Clean Up and Dispose of Trimmings**

* **Gather the Trimmings:** Gather all the trimmings from the tarp or drop cloth.
* **Dispose of Trimmings Properly:** Dispose of the trimmings properly. You can compost them, bag them for disposal, or take them to a local yard waste recycling center.
* **Clean Your Tools:** Clean your pruning tools with soap and water and disinfect them with rubbing alcohol or a bleach solution.
* **Store Your Tools Properly:** Store your pruning tools in a dry place to prevent rust and corrosion.

**Step 7: Post-Pruning Care**

* **Water Deeply:** After pruning, water the boxwood deeply to help it recover from the stress of pruning. Ensure the soil is thoroughly moistened.
* **Fertilize Lightly:** Fertilize the boxwood with a slow-release fertilizer specifically formulated for evergreens. Avoid over-fertilizing, as this can burn the roots.
* **Apply Mulch:** Apply a layer of mulch around the base of the boxwood to help retain moisture, suppress weeds, and regulate soil temperature. Keep the mulch a few inches away from the trunk to prevent rot.
* **Monitor for Pests and Diseases:** Monitor the boxwood regularly for signs of pests and diseases. Treat any problems promptly to prevent further damage.

Specific Pruning Techniques for Different Boxwood Varieties and Shapes

While the general steps outlined above apply to most boxwood trimming, some specific techniques are useful for particular varieties and shapes.

* **English Boxwood ( *Buxus sempervirens*):** This is a classic choice for formal hedges and topiaries. It tolerates heavy pruning and shearing well. When creating a hedge, use a string line to ensure straight lines and even heights. For topiaries, use hand pruners to carefully shape the foliage into the desired form.
* **American Boxwood ( *Buxus sempervirens ‘Suffruticosa’*):** This variety is known for its compact growth habit and is often used for edging and low hedges. It requires less frequent pruning than English boxwood. Simply trim lightly to maintain its shape and density.
* **Littleleaf Boxwood ( *Buxus microphylla*):** This variety is more heat-tolerant than English boxwood and is often used in warmer climates. It has a more natural, rounded shape and doesn’t require as much formal pruning. Simply remove any dead or damaged branches and lightly shape the foliage as needed.
* **Creating a Formal Hedge:** For formal hedges, use a string line as a guide to ensure straight lines and even heights. Trim the hedge regularly, starting in late spring and continuing throughout the growing season. Maintain a slightly wider base than top to allow sunlight to reach the lower branches.
* **Creating a Topiary:** Creating a topiary requires more patience and skill. Start with a young, well-shaped boxwood. Use hand pruners to carefully shape the foliage into the desired form. Remove any stray branches and maintain the shape with regular trimming. Consider using wire frames to guide the growth and shape of the topiary.
* **Rejuvenating an Overgrown Boxwood Shrub:** For severely overgrown boxwood shrubs, a more drastic approach is needed. In late winter or early spring, before new growth begins, cut back the plant by as much as one-third to one-half. This may seem drastic, but it will encourage new growth from the base and interior of the plant. Thin out the interior to improve air circulation and sunlight penetration. Fertilize and water regularly to help the plant recover. Be patient, as it may take several years for the boxwood to fully recover and regain its desired shape.

Common Mistakes to Avoid When Trimming Boxwoods

* **Pruning at the Wrong Time:** Pruning at the wrong time of year can stress the boxwood and make it more susceptible to disease. Avoid heavy pruning in the fall, as new growth may not have time to harden off before winter. Avoid pruning during periods of extreme heat or drought.
* **Using Dull Tools:** Using dull pruning tools can tear and crush the bark, creating entry points for diseases. Always use sharp, clean pruning tools.
* **Shearing Too Deeply:** Shearing too deeply into the foliage can create bare spots and weaken the plant. Shear lightly and frequently to maintain the desired shape.
* **Removing Too Much at Once:** Removing too much foliage at once can stress the boxwood and make it more susceptible to disease. Avoid removing more than one-third of the plant’s total mass at one time. If the boxwood is severely overgrown, prune it in stages over several years.
* **Neglecting Post-Pruning Care:** Neglecting post-pruning care can hinder the boxwood’s recovery. Water deeply, fertilize lightly, and apply mulch to help the plant recover from the stress of pruning.
* **Not Disinfecting Tools:** Failure to disinfect pruning tools can spread disease between plants. Always disinfect your tools before and after pruning each plant.

Troubleshooting Common Boxwood Problems

* **Boxwood Blight:** This fungal disease causes brown spots on the leaves, followed by leaf drop and stem dieback. To prevent boxwood blight, choose resistant varieties, improve air circulation, and avoid overhead watering. If boxwood blight is present, remove infected branches and apply a fungicide.
* **Boxwood Leafminer:** This insect lays its eggs inside the leaves, causing them to become blistered and discolored. To control boxwood leafminer, apply an insecticide in the spring or fall.
* **Boxwood Psyllid:** This insect causes cupping and distortion of the new growth. To control boxwood psyllid, apply an insecticide in the spring.
* **Winter Burn:** This occurs when boxwoods are exposed to cold, drying winds in the winter. To prevent winter burn, protect boxwoods with burlap or an anti-desiccant spray in the fall.
* **Spider Mites:** These tiny pests can cause yellowing and stippling of the leaves. To control spider mites, spray the boxwood with a strong stream of water or apply a miticide.

Conclusion

Trimming overgrown boxwoods can seem daunting, but with the right knowledge and tools, it’s a manageable task. By following the steps outlined in this guide, you can reclaim your garden, revitalize your boxwoods, and enjoy their beauty for years to come. Remember to assess your boxwood’s needs, choose the right pruning techniques, and provide proper post-pruning care. With a little patience and effort, you can transform overgrown boxwoods into healthy, attractive shrubs that enhance your landscape.