Skip to content
The Benefits of Undercutting Hedges

The Benefits of Undercutting Hedges

Undercutting our crop of Portuguese Laurels at Mathias Nurseries

Many of the hedges we sell at Mathias Nurseries are available in containers or rootballed. A rootballed plant (Link to the recently optimised blog) is grown in a field, usually over several years whereras container-grown plants are grown in plastic pots which take up more space and, as such, cost more. 

While container-grown hedges can be planted year-round, rootballed plants can only be planted during the colder months when their roots are not in active growth. For this reason, rootballed plants are only available in the autumn and winter, from mid-October to (usually) the end of March.

Because much of the work can be mechanised with field grown plants, we can grow larger, bushier plants in the ground compared to being grown in a pot. This means you can buy a more established hedge and get the garden you want quicker.

Of course, growing hedges which will be replanted elsewhere requires planning and maintenance. One of the most important tasks we need to complete is undercutting.

In this guide, we’ll discuss rootballed plants and why undercutting hedges is beneficial.

What Is Undercutting?

Undercutting is a process used to prune the roots of each plant below a certain depth. By undercutting a hedge, we reduce the labour required when digging up the plant while reducing the overall size of the root and improving the plant's health.

This process is typically carried out at the start of autumn. This prepares the rootballed plants we’ll sell over the next few months and helps maintain those that will remain in the ground to be sold in the future.

The varieties of hedges this applies to include Portuguese Laurel, Laurel, Thuja, Yew, Holly, and Privet amongst others.

mathias nurseries undercutting hedges

How Undercutting Hedges Works

To undercut a hedge, we’ll drag a large U-shaped blade through the soil beneath the hedge's roots. The blade is connected to a frame on wheels and this frame is attached to a winch behind a tractor. As it’s winched in toward the tractor, a member of our team will ride and steer the frame, ensuring it travels straight along the line of plants to ensure an even cut of the roots.

After this is complete, we use a separate machine to trim the sides of the roots, which leaves them perfectly cylindrical. 

It is then significantly easier to lift the hedge from the ground using a spade when preparing it for sale. Once we’ve dug the hedge up, we’ll wrap the roots in hessian sacking to protect them. This hessian sacking is left on the plant when it is planted in your garden and as it is biodegradable and made from natural material it quickly rots away and the new root growth can easily push through the holes in the hessian. 

The Benefits of Undercutting Hedges

From a practical perspective on the nursery, undercutting makes it easier to prepare a hedge for sale. However, the process improves the overall health of the hedge and increases the chance of it becoming established when you plant it in your garden.

1. Labour Efficiency

Undercutting reduces the physical labour of digging up hedges. Once a plant’s roots have been trimmed, we can easily remove it from the ground using a spade. This makes the process much quicker. 

Reduced labour also helps us keep the cost of the rootballed hedge lower for you which is why rootballed hedging plants are often cheaper than container grown plants.

2. Limits Root Size

When an established hedge is dug from our fields for transplanting into your garden, the roots can easily become damaged if they have not been prepared correctly. This is because you’ll likely break a larger percentage of the root structure in the digging process.

Damaged roots can reduce the chances of the hedge becoming established.

If we undercut and root prune each plant in the early autumn, it limits the size of the roots and encourages a second growth of dense fibrous root which is much better for transplanting to its future home, and it increases the chances of success. 

Because we’ll sell all the plants we dig up, we don’t want the root ball to be too big as they can then get incredibly heavy and difficult to transport. Undercutting annually helps us limit the size of the roots so your plant is healthy whilst still being easily handleable.

Mathias nurseries undercutting hedges

3. Improves Root Quality

Undercutting is also considered to be the act of root pruning. Whenever the roots of a hedge are cut back, they grow back stronger, denser, and more fibrous. The healthier the roots, the greater the chances of success when you transplant the plant to your garden. A plant with denser fibrous roots will establish much more quickly in your garden.  Please see the picture below which shows two identical plants dug out of our fields in December.  The plant on the right was undercut in September.  As you can see the plant that had been undercut has a much stronger and dense root system which will lead to significantly better growth the following year.

While we undercut hedges before removing them, we will also perform the same task on those which will remain in the ground for next year. 

How to Plant Your Rootballed Hedge

We work hard to ensure your hedge is strong and healthy. To get the best results, plant your rootballed plant as soon as possible after purchase—ideally within the first couple of days. Leave the hessian sacking on the Rootball when planting as it will usually do more damage to the plant to try and remove it.  Don’t forget to water your new hedge after it has been planted as it will be stressed from being dug up from our fields so may be thirsty.

The season for planting rootballed hedges usually runs from mid-October to the end of March but it varies from species to species and can be dependent on the weather conditions.  For example, if October proves to be incredibly hot and dry, it may not be safe to start digging rootballed plants, so the season may then start slightly later.  Varieties such as Thuja plicata and Taxus baccata are usually the earliest rootballs that will be available as they tend to stop actively growing earlier than Prunus varieties (Common Laurel and Portuguese Laurel)

For the highest chance of the hedge becoming established, plant earlier in the season. It’s better to plant your rootballed hedge in the autumn instead of spring. Similarly, taller plants have a higher chance of success if they’re planted early.

Learn more about the differences between rootballed, bare-root, and container-grown hedges.

mathias nurseries undercutting hedges

Rootballed Hedges at Mathias Nurseries

Rootballed hedges are an economical way of producing impressive hedges. They’re often taller, bushier, and cost less than their pot-grown counterparts; however, to become established, they need the right start in life.

All our rootballed hedges are undercut, so you get the best plant possible. We also want your rootballed hedge to thrive, so our team is always on hand to provide you with expert advice on selecting the right variety and planting. Get in touch for more information on any of our hedges or products.

Previous article Care and Maintenance: When to Cut Leylandii Hedges
Next article The Best Time to Plant Hedges in the UK - Now!