Trimming a Hedge: Shape Cuts, Hard Pruning and the Right Timing
How to keep your hedge dense and in shape – including the trapezoid cut and the rules of German nature conservation law
Disclaimer
This guide has been prepared with great care. Nevertheless, we accept no warranty for the accuracy, completeness or currency of its contents. You follow this guide at your own risk – any liability for personal injury, property damage or financial loss arising in connection with its use is excluded. The contents do not replace professional advice for your individual situation. Always observe the manufacturer instructions of your tools and materials as well as applicable local regulations (e.g. building codes, neighbour law, utility line enquiries before digging). Work on electrical, gas or water lines and on load-bearing structures must only be carried out by qualified professionals.
How to keep your hedge dense and in shape – including the trapezoid cut and the rules of German nature conservation law
Whether privet, hornbeam, thuja or cherry laurel – without trimming, every hedge grows wider year by year, goes bare on the inside and loses its shape. Two kinds of cut need to be distinguished: the gentle shape cut, which only removes the annual growth, and the hard pruning back into old wood, which rejuvenates a hedge that has grown out of shape. Different rules apply to each – both in craft and in law. The most important point first: under Section 39 of the German Federal Nature Conservation Act (BNatSchG), it is prohibited to cut hedges back radically or down to the stump between 1 March and 30 September. Gentle shape and maintenance cuts that remove the season’s growth are permitted all year round – provided no birds are nesting in the hedge.
Tools
- Hedge trimmer (manual, corded or cordless)
- Loppers for thicker shoots
- Hand saw for old wood
- Sturdy ladder or trestle
- Mason’s string and two rods as a cutting guide
Materials
- Tarpaulin or garden sacks for the clippings
- Resin remover or care spray for the blades
- Work gloves and safety glasses
Step by Step
Choose the timing and observe the legal rules
The classic shape cut is done in late June after the first flush of growth, with a second cut in late summer if needed. Radical pruning into old wood or cutting a hedge down to the stump is only permitted from 1 October to the end of February under the German Federal Nature Conservation Act (BNatSchG) – between 1 March and 30 September it is prohibited to protect nesting birds. The gentle maintenance cut of the annual growth remains allowed all year.
Check the hedge for bird nests
Search the hedge thoroughly for occupied nests before every cut – even the permitted shape cut must wait while birds are breeding in it. Watch the hedge for a few minutes: if adult birds repeatedly fly to the same spot, postpone the cut until the young have fledged.
Set up a cutting guide
Stretch a mason’s string between two rods at the desired hedge height – hedges cut by eye reliably end up wavy. Lay a tarpaulin under the hedge; this saves you laboriously raking the clippings out of the border later.
Cut the sides in a trapezoid shape
Cut the flanks so the hedge stays about 10–15 cm wider at the bottom than at the top. This trapezoid shape ensures the lower branches also receive light – hedges cut vertically, or even wider at the top, go bare from below. Guide the trimmer in calm, sweeping movements from the bottom upwards.
Trim the top
Cut the top along the tensioned string. From the ladder, only ever work within comfortable reach and reposition the ladder one more time rather than leaning out sideways. For the shape cut, the rule is: remove only this year’s growth, do not cut into older wood.
Rejuvenate old hedges (October to February)
Badly bare or overgrown deciduous hedges such as privet, hornbeam or field maple tolerate hard pruning into old wood during the winter months and will sprout again. Caution with most conifers: thuja, cypress and spruce do not regrow from old, brown wood – never cut deeper than the green zone. Yew is the exception and forgives even radical cuts.
Dispose of clippings and care for your tools
Healthy clippings can be shredded for mulch or composted; recycling centres accept larger quantities as green waste. Afterwards, clean the trimmer blades of resin and plant sap and oil them lightly – sharp, clean blades cut instead of crushing and keep the cut surfaces healthy.
Safety First
- Only set up the ladder on level, firm ground and never lean out sideways – reposition it more often instead. For tall hedges, a trestle or work platform is the safer choice.
- With corded hedge trimmers, always route the cable over your shoulder and behind the machine, and only work from a socket protected by an RCD (residual current device). A severed cable is the most common accident with these tools.
- With cordless tools, remove the battery before any cleaning or clearing of jams – otherwise the blades start at the touch of a button.
- Wear safety glasses and gloves: branches springing back and splintering wood quickly hit the face.
Mistakes You Should Avoid
Cutting wider at the top than at the bottom
If you let the hedge spread at the top, you rob the lower branches of light – the hedge goes bare from below and loses its screening effect. The trapezoid shape with a narrow crown is not a styling detail but the foundation of a permanently dense hedge.
Hard pruning at the wrong time of year
Cutting back into old wood between 1 March and 30 September violates the German Federal Nature Conservation Act (BNatSchG) and, depending on the federal state, can result in substantial fines. Rejuvenation cuts belong in the winter months – which is also when the plant copes with them best.
Trimming in blazing sun or frost
Freshly cut leaves and shoots scorch in the midday sun; in frost below about −5 °C the wood splinters and the cut surfaces die back. Ideal is an overcast, dry day – the cut surfaces then dry off without damage.
Common Questions
When are you allowed to trim a hedge?
Gentle shape and maintenance cuts that only remove the annual growth are permitted all year round – provided no birds are nesting in the hedge. Radical pruning and cutting down to the stump are only allowed from 1 October to the last day of February under the German Federal Nature Conservation Act (BNatSchG).
How often does a hedge need trimming?
Formal hedges that tolerate cutting well, such as privet, hornbeam or cherry laurel, are trimmed once or twice a year: the main cut in late June and a corrective cut in late summer if needed. Slow-growing species such as yew manage with one cut per year.
How hard can I cut a hedge back?
A shape cut removes only the annual growth. Pruning into old wood is fine for most deciduous hedges during the winter months – ideally staged over two to three years. Most conifers apart from yew will not regrow from old wood.
Why is my hedge going bare at the bottom?
The cause is almost always lack of light: the hedge was cut vertically or wider at the top, so the lower branches are shaded and die off. The trapezoid cut – 10–15 cm wider at the bottom than at the top – prevents this. Deciduous hedges that have already gone bare can often be saved with a winter rejuvenation cut.
In what weather should you trim a hedge?
A dry, overcast day is ideal. Direct midday sun scorches freshly cut shoots, and in harder frost the wood splinters. Do not trim in rain either – wet cut surfaces are more prone to fungal infection, and handling electric tools is then off-limits anyway.
When is a professional worth it?
With tall, long or long-neglected hedges, DIY equipment reaches its limits: working above head height from a ladder is a considerable accident risk, and rejuvenating old shrubs takes experience so the hedge regrows densely. We take on hedge trimming at any scale – with professional equipment, a safe stand and including removal of the clippings. And if the hedge has long since turned into trees, we are the right partner with our tree care and tree felling services: professional, insured and with the nature conservation deadlines in mind.
