How To Trim Overgrown Hedges

Overgrown hedges look bad and can cause numerous other issues, including increased risk of plant disease, pest infestations, and potential damage to nearby structures. With the right pruning techniques, you can get your hedges back in check and keep them healthy. In the video above, This Old House landscape contractor Roger Cook shows how to refresh neglected privet hedges.

Why Hedges Overgrow

Several factors contribute to hedge overgrowth, such as the following:

• Choosing fast-growing hedge species
• Excessive fertilization
• Incorrect pruning techniques
• Lack of regular maintenance

When left unchecked, overgrown hedges can lose their shape, develop bare patches that are hard to correct, and even pose safety risks.

Tools for Trimming Overgrown Hedges

You’ll need the right equipment for effective pruning that minimizes damage to your plants. Here’s what you should have in your toolkit.

Hand Pruners

Hand pruners are ideal for trimming small branches and precise shaping. They’re essential for removing individual stems and maintaining the hedge’s overall form.

Bypass Loppers

Bypass loppers cut thicker branches that hand pruners can’t handle. They provide the leverage needed to trim larger stems, making them indispensable for rejuvenating overgrown hedges.

Hedge Shears

Hedge shears are the tool of choice for shaping and trimming the outer layers of the hedge. They allow for quick, even cuts across the hedge’s surface.

Safety Equipment

Don’t forget to prioritize safety when trimming hedges. Wear this safety gear:

• Closed-toe shoes
• Long-sleeved shirt and pants
• Protective eyewear
• Thick gloves

Techniques for Trimming Overgrown Hedges

Proper pruning techniques will rejuvenate instead of harm an overgrown hedge. Follow these steps to restore your hedge’s health and appearance.

Assessing the Hedge

Before beginning, carefully examine the hedge to determine its overall condition and identify problem areas. Look for bare patches, dead or diseased branches, overly thick growth, and uneven shapes or sizes.

Removing One-Third of Older Stems

For super overgrown hedges, simply cutting all the older stems may result in an unattractive appearance and diminished privacy. Instead, Cook recommends removing one-third of the older stems to allow sunlight to penetrate the hedge’s interior. This technique, known as rejuvenation pruning, encourages new growth and helps revitalize the hedge.

Here’s how to do it:

1. Identify older, thicker stems growing out of the hedge.
2. Use bypass loppers to cut these stems close to the ground.
3. Where one stem branches into two, cut just above the Y-shaped split to encourage branching.
4. Shape the hedge by trimming the top narrower than the bottom, allowing sunlight to reach lower branches.
5. Use hand pruners to thin out smaller stems and create a more open structure.

Maintaining New Growth

As you prune, be mindful of new growth. Avoid cutting back into bare wood, as this can hinder regrowth. Encourage fuller growth by selectively pruning to stimulate branching. Identify and preserve new shoots and leaves.

Hedge Trimming Timing and Frequency

The best time to trim most hedges is during their dormant season, typically in late winter or early spring before new growth begins.

Seasonal Considerations

Different types of hedges may require trimming at specific times.

• Deciduous hedges: Prune in late winter or early spring.
• Evergreen hedges: Trim in late spring or early summer.
• Flowering hedges: Prune after blooming has finished.

Frequency of Trimming

Fast-growing hedges may need trimming 2-4 times a year, while slower-growing or formal hedges might only require annual or biannual maintenance. How often you should trim your hedges depends on these factors:

• Climate and growing conditions: Hedges in mild, temperate climates may need less frequent trimming compared to those in harsher climates or poor soil conditions. The ideal conditions vary by species, but most hedges need well-drained, slightly acidic to neutral soil, full sun to partial shade, consistent moisture with good air circulation, and appropriate space.
• Desired shape and size: If you like your hedges to have a specific shape or size, you’ll need to trim them more often to maintain their appearance.
• Growth rate of the hedge species: Fast-growing hedge species, like Leyland cypress or privet, often require more frequent trimming to prevent them from becoming overgrown. Slow-growing species, such as Boxwood, need less frequent maintenance.
• Overall health of the hedge: Healthy, fast-growing hedges may need more frequent trimming to maintain their shape and density. A hedge with health issues, such as disease or pest problems, might require less frequent trimming or special care to promote recovery.

Hedge Aftercare and Maintenance

Proper aftercare ensures the hedge recovers and thrives after trimming. Cook recommends applying a shrub fertilizer in the spring following pruning. This helps promote new growth and strengthens the hedge. The type of fertilizer you should use depends on the shrub and growing conditions. A balanced fertilizer with equal or near-equal amounts of nitrogen (N), phosphorus (P), and potassium (K) is often appropriate for shrubs. An example of a balanced fertilizer is 10-10-10 or 12-4-8. Balanced fertilizers are good for general maintenance and can be used in the spring to support overall growth and health.

Adequate watering is also crucial, especially after heavy pruning. Based on rainfall and soil conditions, the hedge may only need a little water after pruning. After watering, mulch around the base of the hedge to retain moisture and regularly provide deep watering during the growing season.

Ongoing Maintenance

To keep your hedge healthy and well-shaped throughout the year, monitor for signs of pests or diseases. Lightly trim throughout the growing season to maintain shape. Remove dead or damaged branches promptly. Repeat the rejuvenation pruning process every few years as needed.

Common Hedge Trimming Mistakes To Avoid

When trimming overgrown hedges, be aware of these common pitfalls:

• Cutting too much at once, which can stress the plant
• Failing to maintain the proper shape, leading to top-heavy hedges
• Ignoring the interior of the hedge, resulting in bare patches
• Neglecting to clean and sanitize tools between cuts
• Pruning at the wrong time of year for your specific hedge type

Tip: Make sure to clean your tools between cuts, especially if moving from one hedge to another. When you cut hedges, your tools can pick up bacteria, fungi, and viruses from one plant and transfer them to another. Dirt, sap, and plant residue can also build up on the blades, making them sticky or dull, resulting in ragged, uneven cuts that can stress the plants.

Our Conclusion

Trimming overgrown hedges requires patience, proper techniques, and the right tools. By following the steps outlined in this guide, you can rejuvenate your hedges and maintain their health and appearance for years to come. Remember to prune regularly, fertilize appropriately, and always prioritize the plant’s overall health.