Trimming cypress trees

Cypresses will not revive well if you cut back to their old wood. Read on to find out when to trim Cypress and how you can do so correctly.

Cypress hedge on a garden plot
Regular trimming keeps cypress hedges in shape.

Overview: Trimming cypresses

  • You should trim cypress once a year to keep the hedge in shape

  • Standalone plants generally do not need to be trimmed

  • Never cut into the old wood of a cypress – it will not generate any new growth. 

  • Use a hedge trimmer with sharp blades for shaping in June

  • Use shrub shears to cut cypress into topiary shapes twice a year

  • Do not cut the top of cypress until it has reached the desired height.

When is the best time to trim a leyland cypress? 

The growth of the plant and the German Federal Nature Conservation Act both dictate when you should and can trim a Leyland Cypress. If you have a standalone tree in your garden, you will not need to trim it until it gets too tall. On the other hand, you should trim a cypress hedge once or twice a year to keep it thick and help it maintain its shape. The ideal time to lightly cut these types of plants is around June 24, when the growth phase is over.

If your cypress has become too tall, you can cut it to the desired height at the end of February. Choose a day that is as frost-free and cloudy as possible, with dry weather. This is the best way to ensure the plants can tolerate a severe cut.

A man on a ladder timming a leyland cypress tree on a sunny, overcast day

A mild overcast day is perfect for trimming cypress.

Too much sunshine can scorch the cut sections, while rain can cause both mould and infections. 

In terms of the law, note the period from 1 March to 30 September: paragraph 39(5) of the German Federal Nature Conservation Act prohibits the deep pruning of hedges and shrubs during this time. This also applies to the pruning of Leyland Cypress trees.

For animal welfare reasons, and particularly for the protection of birds, it is forbidden to cut cypresses back hard. You may only make light shaping cuts during this time, and only provided there are no birds nesting in the plants. You should check the cypress for birds before starting work.

Trimming cypress correctly

With the right tool and a few useful tips, you’ll be well prepared to prune your cypress and keep your hedge in shape.

Beware of poisonous stems

Cypress contains toxic substances that can cause symptoms of poisoning on consumption, and skin irritation and inflammation on contact. Always wear gloves and personal protective equipment when trimming cypress.

A cypress with visible brown old wood after radical pruning

Old wood on cypress plants does not tolerate being cut.

How to cut cypress back hard 

Cypress generally does not like very deep pruning. A radical cut can even make the plant die back. Rather than pruning cypress trees back hard, it is advisable to cut them into shape annually. Even large standalone trees do not usually recover after being cut back hard.

If you reduce the height of a cypress, it will remain more or less at the cut height – upward-growing side shoots may eventually cover the sections of the main stem that have been cut. So you should avoid radically cutting this type of plant. 

Shaping cypress 

Cypress is easy to shape if you follow our trimming tips. For hedges, a trapezoidal shape – wider at the bottom, narrower at the top – is perfect for ensuring that all parts of the plant receive consistent light, so it can grow well and remain dense. 

Beware of cutting too far when shaping your cypress: they does not forgive having their old wood cut into. Unlike yew, cherry laurel and box, conifers such as thuja and cypress do not produce new growth after excessive pruning. The affected spots usually remain bare and unsightly. So you should proceed with caution and only lightly cut the stems. You can achieve uniform results on this plant by using your trimmer from top to bottom; this method prevents the flexible branches from bending away from the blade.

Ladder leaning against a tall cypress hedge under a blue sky
Cypress pruning requires care.

Then even standalone plants can be cut into artistic shapes, or topiary figures. Spheres, clouds, spirals and cones are some of the most popular shapes you can cut a cypress into. To do this, you can use handy shrub shears such as the STIHL HSA 26, which has a short bar length combined with an ergonomic rubberised handle and is ideal for precise detailed cuts. 

 Shortening your cypress

Trimming the height of a cypress will permanently affect its future growth behaviour. The top of the plant contains cells that responsible for top growth; if you cut the top of a cypress trunk and remove these cells in the process, the cypress will no longer grow taller, but will instead tend to grow outwards.

Densely growing cypress trees in a row

Regular shaping cuts help maintain the desired width.

This, in turn, can mean that the inside of the plants loses leaves more quickly, and it becomes less effective at blocking the view. This means that regular trimming of your cypress tree becomes even more important after you have shortened it

You should only shorten a cypress once it has reached the desired height. The ideal time to do this is on a frost-free, dry and cloudy day at the end of February. The impending growth phase will mean lots of fresh shoots that will soon cover the cut sections.

Maintaining cypress 

Regular trimming of new growth is part of proper cypress maintenance. In order to take the best possible care of your cypress, you should remove dead, dried-out or diseased branches as soon as you notice them. 

We also recommend fertilising your cypress. Applying an organic long-term fertiliser in spring contributes to optimal growth and plant health. If the soil is particularly sandy, you can add a second dose in June or July at the latest. In September or October, you should provide young plants in particular with potassium fertiliser to make them more resilient against cold and frost. You can find out even more information about the proper supply of nutrients for your hedge in our guide on “Fertilising hedges”.

Ensuring that your cypress plants get enough water all year round is just as important as ensuring they have the right supply of nutrients. The soil should always be kept moist, as cypresses must not be allowed to dry out. However, they also cannot tolerate waterlogging. For this reason, you should prepare the soil before planting cypresses, for example by adding drainage in very loamy soils or when planting in pots. Remember to keep your cypress moist in winter too. On frost-free days, it is best to water the plant with slightly warm water.

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