When to Trim a Hedge in Geneva: Calendar and Tips

To know when to trim a hedge, remember two benchmarks: a main cut outside the periods of strong growth, and a lighter maintenance trim during the season. Flowering hedges are trimmed just after they flower, and severe cutting should be avoided in spring and early summer, when birds are nesting. In Geneva, also avoid very hot days and frosty days.

Main trim and maintenance trim: two different jobs

A well-kept hedge generally receives two kinds of work, which differ in purpose and in timing.

• The main trim restores the hedge’s shape and height. It removes a larger share of the year’s growth, sometimes a little more, and is done at a time when the plant is least vulnerable.
• The maintenance trim is a lighter pass that keeps the lines tidy between main trims. It removes only the young shoots that stick out.

This distinction avoids two common mistakes: cutting everything back in one go once a year, at the risk of shocking the hedge, or making lots of small passes without ever correcting the overall shape. The exact number of passes depends on the species, the vigour of the hedge and the look you want. A formally clipped hedge, for example, needs more passes than an informal one.

If you would like to hand this work over, the page on hedge trimming describes the services available.

When to trim, by species

The right moment depends mainly on what the hedge is: evergreen, deciduous or flowering.

Evergreens

Evergreens keep their leaves or needles all year round: thuja, cherry laurel, photinia, yew, box. They are generally trimmed outside periods of frost and intense heat, with a more marked main trim at the end of winter or in late summer, and a light maintenance trim in between.

One point deserves attention with conifers such as thuja: they regrow very poorly when cut into bare wood, that is, below the green part. An overly severe trim can leave a lasting gap. It is better to trim regularly and lightly than to make up for years of neglect in a single session.

Deciduous hedges

Deciduous plants lose their leaves in winter: hornbeam, beech, field maple, privet depending on the climate. They tolerate a firmer cut well, as they bounce back easily. The main trim is best done outside the growing season, and a maintenance trim thins the hedge out during summer.

Flowering hedges

For shrubs kept for their blooms (forsythia, weigela, lilac, spring spiraea), the rule is simple: trim just after flowering. Trimming beforehand would cut off next year’s buds and deprive you of flowers. Mixed hedges, which combine several species, are treated species by species, or trimmed gently so as not to sacrifice the flowering of some of them.

This table gives general guidance. For the choice of species itself, our guide to the privacy hedge and its plants will help you decide before planting.

Nesting, heat, frost: periods to avoid

Three situations should make you postpone trimming.

1. Nesting. In spring and early summer, many birds nest in hedges, which offer shelter and food. Severe trimming at this time destroys occupied nests. If work is truly necessary, limit yourself to a small adjustment and first check that no nest is present. Planning the main trim outside this period solves the problem.
2. Intense heat. A freshly trimmed hedge exposes leaves and twigs that were previously sheltered. In very hot, sunny weather, the foliage can scorch. Choose an overcast or mild day.
3. Frost. Trimming during a frost damages the cuts and exposes the tissues to the cold. Wait for a thaw.

These precautions are simple horticultural common sense, and they protect your hedge as much as the wildlife that lives in it. To place these tasks within the year, the Geneva garden calendar gives an overview of the work to do season by season.

Trimming a young hedge: formative pruning

A newly planted hedge is not trimmed like a mature one. The aim is to make it thicken from the base so that it does not become bare at the bottom.

• After planting, shorten the young plants by part of their height, following the advice given for the chosen species: this encourages branching.
• In the following years, trim lightly each year, keeping the base slightly wider than the top. This trapezoid shape lets light reach the bottom.
• Do not let the hedge grow to its final desired height before trimming it: it would be bare at the base, and this flaw is hard to put right.

Patience pays: two or three years of careful formative pruning give a dense hedge for many years.

Equipment and garden waste

The right tool depends on the size of the hedge and the species.

• Secateurs for large-leaved plants such as cherry laurel: cut with a hedge trimmer, the leaves shred and turn brown along the edge.
• Hedge trimmer (electric, battery-powered or petrol) for small-leaved or needle hedges. A well-sharpened blade gives a clean cut, which heals better.
• Hand shears for small precision jobs.
• Stable ladder or platform for tall hedges: working at height is the main risk of this job.

Remember to protect your eyes and hands, and to check for cables or nests before starting. Garden waste often amounts to a large volume: lay a tarpaulin on the ground before trimming to make collection easier, then dispose of the clippings according to your commune’s rules. The branches can also be shredded to use as mulch or compost material, provided they are healthy.

Regular hedge care fits naturally into garden maintenance throughout the year.

In Geneva: what changes

The canton has its own particularities, which affect the trimming calendar.

• The Lake Geneva climate is relatively mild near the lake, but winters can bring periods of frost. Check the weather before working.
• Dry summers weaken hedges: after trimming, appropriate watering helps the plants recover, especially young ones. Avoid trimming during a heatwave.
• The bise (the cold north wind) dries out and damages exposed hedges. A hedge battered by wind needs particular attention, and some species withstand it better than others.
• Clay soils, common in the canton, hold water in winter and harden in summer: conditions that weigh on the roots and make upkeep more important.
• Distance and height relative to your neighbour. Geneva cantonal law sets rules on distance and height for plantings near the property boundary. No values are given here: check with your commune or a professional before planting or trimming a boundary hedge, to avoid a dispute. If your hedge runs alongside a fence, also see our fencing and metal trellis solutions.

Practices vary from one area to another. Depending on whether your garden is on the left bank, as in Cologny, or on the right bank, as in Versoix, exposure to wind and soil type change, and the ideal calendar changes with them.

Calling on a landscape gardener

A large hedge, difficult access or lack of time often justify handing the trimming over to a professional. On Mon-jardinier.ch, you describe your project and a qualified landscape gardener contacts you within 24 hours to arrange a visit on site. The quote is free and without obligation: it takes into account the length, height and species of your hedge, as well as the removal of garden waste. You can request a quote in a few minutes.

Frequently asked questions

What is the best time to trim a hedge?

There is no single date, as it all depends on the species. As a general rule, the main trim is done outside nesting season and periods of intense heat and frost, and the maintenance trim is spread across the season. Flowering hedges are trimmed just after they flower.

Can you trim a hedge in spring?

A light adjustment is possible, but severe trimming should be avoided in spring and early summer, as birds nest in hedges. Always check for nests before working. For a major trim, it is better to wait until the end of the nesting period or to work earlier.

When should I trim a thuja or a cherry laurel?

These are evergreens: a main trim at the end of winter or in late summer, supplemented by a light maintenance trim, suits most cases. For thuja, do not cut into wood with no greenery, as it will not regrow. For laurel, prefer secateurs to a hedge trimmer so as not to shred the large leaves.

What hedge height is permitted on a property boundary?

Geneva cantonal law sets rules on distance and height for plantings close to the boundary. The precise values are not given here: check with your commune before planting or trimming, especially if a neighbour has already voiced a complaint.

What should I do with the clippings?

Lay a tarpaulin on the ground before trimming so you can collect everything easily, then dispose of the clippings according to your commune’s rules. If the branches are healthy, you can shred them to make mulch or a compost addition.

For more ideas on work through the year, see all of our garden guides.