Hedge trimming: when and with what?

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Hedges are one of the most popular elements in garden design. They serve as a natural visual, wind and noise barrier, and decoratively separate different areas in the garden. In addition, many insects and bird species use hedges as a habitat or for food, while other animals use them as a hiding place or winter shelter, such as hedgehogs or hares.

To keep them looking their best, hedges must be well-maintained: in addition to watering and nutrient supply (e.g., through compost or suitable fertilisers), hedge trimming is especially crucial for ensuring healthy growth. This involves either protecting the hedges from overgrowth through a form cut or supporting dense, even growth through a cutback.

However, when you want to trim your hedge, you must consider various factors:

• What is the right time for hedge cutting?
• How often should the hedge be trimmed?
• Which hedge trimming tools and cutting techniques are appropriate for this?

In this guide, we have compiled the most important information and tips to answer these questions.

Why is hedge maintenance so important?

A hedge consists of individual shrubs or trees that are planted close together and gradually grow into dense shrubbery. Without regular pruning, each shrub or tree would grow upwards and form a (more or less) bare trunk with a dense leaf crown. If you want a dense green hedge that can serve as a decorative garden feature, provide privacy, and serve as a habitat for wildlife, it is important to avoid this natural growth pattern. This is where bush and shrub trimming comes in. There are two ways to do this:

• Form or maintenance pruning: To maintain a uniformly dense hedge, it is important to regularly shape the small trees or shrubs. New, fast-growing shoots are trimmed to create an even surface.
• Rejuvenation pruning: To prevent older hedge plants from growing exclusively upwards and to avoid a sparse or misshapen appearance at the bottom, the branches are heavily pruned back or the entire hedge is cut back to the ground. This means that only about 10 to 15cm of the rootstock is preserved, which can then develop new shoots that will grow back into the hedge.

For all hedge plants (except conifers!), a rigorous rejuvenation pruning is necessary after about 10 to 20 years, which entails cutting the hedge back hard to the ground. This allows you to completely rebuild older, sparse leafy or flowering hedges that no longer produce flowers. If possible, do not cut the entire hedge with a radical pruning, but trim a different section each year over several years. This will maintain the hedge’s visual and protective function, and the hedge’s inhabitants will retain their habitat.

Different types of hedges and their influence on pruning 

Timing, frequency, and shape are crucial when it comes to creating a beautiful, evenly dense hedge. However, when and how often you should trim a hedge depends on the type of hedge – whether they are shrubs or conifers, flowering or evergreen, fast-growing or slow and wide. The different requirements for hedge cutting begin as early as the first year after planting:

Hedgerow species	Growth characteristics	Example	Trimming
Deciduous trees	Tall growing	• Privet • Hawthorn • Snowberry • Field maple	• Strongly prune in the first years to promote vigorous growth at the base. • Regularly prune young shoots to encourage good branching. • Central shoots must not reach their final height too quickly.
Deciduous trees	Bushy	• Hornbeam • Hazel • Beech	• Cut back larger side shoots by about one third and remove small branches to stimulate vertical growth. • Later, only prune during the growing season.
Coniferous trees		• Thuja • False cypress • Yew	• Avoid trimming the hedge in the first year to allow the young plants to establish well. • Then, prune side shoots as necessary. • Never cut back the main stem, as it will not produce new growth in conifers.

In general, you need to carefully prune all young hedges in the first few years to slowly build them up to the desired height and width. The specific things to watch out for depend on the characteristics of each plant species.

When should you prune a hedge?

If you want to heavily prune or cut back your hedge to the ground, you should do so before March 1st. This is because plants can tolerate the pruning during this time and will quickly regrow in the spring, so you can enjoy a green hedge again by summer. Another reason to cut your hedges before this date is because breeding season for birds starts around this time and runs until August. Under Section 1 of the Wildlife and Countryside Act of 1981 heavy pruning of hedges between March and August is strictly prohibited if you are aware that the hedge is a nesting place for birds. Intentionally causing damage to or destroying this habitat is therefore an offence.

The law applies to both public and private gardens. While it is possible to prune hedges during the prohibited period, only minor corrective shaping and maintenance pruning is recommended to protect nesting birds and other hedge inhabitants. For these shaping cuts, you should follow the growth and flowering characteristics of your plants:

• Many deciduous trees have their main growth phase in May and June. The young shoots are then shaped from the end of June to mid-July.
• Decorative flowering hedges such as forsythia, lilac, sea buckthorn, or jasmine are pruned after flowering.
• Evergreen hedges should be trimmed in late summer to prevent resin formation or a second growth phase.

For very strong and fast-growing hedges like hornbeam or privet, two shaping cuts may be necessary each year. In this case, the first cut is recommended in spring and the second after summer.

Regardless of the timing, always ensure that there are no bird nests or winter quarters in the hedge before you trim it.

How to trim hedges: a step-by-step guide

Tools for hedge cutting

There are various gardening tools available for cutting hedges. Generally, the thickness of the branches and the height of the hedge determine which tool is best suited.

• Shears: To trim young shoots or cut shrubs, a regular pair of garden shears is sufficient. They are also suitable for large-leaved hedge plants where too many leaves would be cut by a larger hedge trimmer, resulting in browning.
• Manual hedge trimmer: With a hedge trimmer, you have a powerful tool that quickly restores even large, heavily overgrown hedges to their desired shape. A manual hedge trimmer is well-suited for small to medium-sized hedges, as it is handy and can reach difficult spots easily.
• Powered hedge trimmer: Using a powered hedge trimmer significantly reduces the time required to trim your hedges. An electric hedge trimmer is a good choice for gardening, as battery-powered and corded hedge trimmers are still relatively lightweight and operate quietly. However, using a fuel-powered hedge trimmer (gasoline or diesel) generates a high level of noise. The advantage, however, is that they are much more powerful and suitable for very large hedge areas in public parks or on industrial sites.
• Telescopic hedge trimmer: These powered hedge trimmers come equipped with a telescopic pole, enabling you to shape tall hedges even in the upper regions with ease.

FAQ on hedge trimming

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