← All guides · Seasonality · Updated October 2026

Box hedge trimming in Chatham. A year-round cutting calendar.

Box (Buxus sempervirens) looks after itself between cuts. What gets it into trouble is cutting at the wrong time, in the wrong weather, with unclean blades, and then leaving the clippings to rot at the base. Here is how the year runs for box hedges across ME1–ME8.

1. January – February: winter review

   Box is semi-dormant in winter but is not as cold-hardy as yew or hornbeam. A hard frost browns exposed leaf tissue; that is weather damage rather than disease, and the plant usually grows through it by May. This window is useful for assessing the overall shape of the hedge, spotting frost-cracked stems, and cutting out any clearly dead branches while the structure is visible against the winter light.

   A full renovation cut, reducing an old or misshapen box hedge back hard into old wood, is best timed for late February or early March before growth begins. Box will regenerate from old wood if the plant is otherwise healthy. Don't attempt a renovation cut on a specimen already stressed by blight or sitting in waterlogged ground, both are worth avoiding on any heavy or poorly drained ground.

2. March – late May: the growth watch

   Box starts into growth slowly, typically showing new lime-green tips from late March. The first flush is soft and will wilt at the cut edge if you trim too early, so leave it to harden. The Wildlife and Countryside Act 1981, section 1 makes it a criminal offence to damage or destroy a nest while it is in use or being built, and the RSPB advises avoiding hedge cutting from 1 March. Box hedges are used by wrens and dunnocks. Give any hedge a visual check before cutting throughout this period. On conviction the penalty can be a fine, up to six months in prison, or both, counted per nest; failing to look first is no safeguard.

   Box tree moth (Cydalima perspectalis) is now widespread across south-east England. The caterpillars are active from spring and feed inside the foliage behind protective webbing. They are easily missed until the damage is already visible. A careful look through the hedge from mid-April costs little and limits the spread of larvae via cutting-tool contact later in the season. Our pest and disease calendar has more detail on managing box tree moth and box blight month by month.

3. Late May – Derby Day (first Saturday in June): the first cut

   The established timing for the first box cut is Derby Day. By then the spring flush has finished and the new leaves have hardened enough to clip cleanly. Cutting earlier is a mistake: soft growth wilts at the cut edge and browns, which looks alarming but is simply physical damage rather than disease. Rushing the cut also means cutting into tissue that is still working hard, which stresses the plant.

   Tool hygiene matters more for box than for almost any other hedge species. Box blight (caused by the fungus Calonectria pseudonaviculata, formerly Cylindrocladium buxicola) enters through cut leaf tissue. Use sharp blades; a blunt trimmer crushes leaf cells rather than cutting them cleanly, creating far more entry points. Clean and disinfect blades before moving from one box hedge to another. Cut on a dry, overcast day; direct sun on freshly cut box scorches the leaf margins brown. Remove all clippings from the base of the hedge and bag them rather than composting. Infected clippings left on the ground are the primary source of blight reinfection year on year.

   Derby Day falls within the 1 March to 31 August period that RSPB guidance advises avoiding, and the 1981 Act protects any nest in use. Give the hedge a visual check immediately before cutting, looking for birds flying repeatedly in and out and listening for chick calls from inside. If a nest is active, leave that section and return once the young have fledged.

4. Late July – August: the second cut

   A single cut a year is enough for most established box hedges. A second light trim in late July or early August keeps the shape crisp through autumn and gives any new growth time to harden before the cold arrives. Skip the second cut if the weather has been persistently warm and humid; those are the conditions in which box blight spreads fastest, and opening fresh cut surfaces in such weather invites infection. The ideal window is a run of dry, overcast, breezy days in late July or the first half of August.

   The RHS says a second generation of box tree moth appears in late July or early August. Check for webbing and fresh feeding damage before you cut, and remove any infected material as you go. The nesting closure runs notionally to 31 August, so check for late broods in any dense adjacent planting before the second box cut.

   Martin Fish of the Pots & Trowels YouTube channel covers box trimming technique in useful detail, including how to decide whether a hedge needs one cut or two in a given season. His "Box Trimming Mini Masterclass" video is at youtube.com/watch?v=G9GT8e-eQNY.

5. September – October: post-season assessment

   After the summer cuts, walk the hedge slowly and look for brown patches with black streaking at the base of affected stems. That combination is box blight. If you find it, cut the affected growth back to clean wood on a dry day, bag the removed material, and sterilise all tools before moving on. Uniform surface browning without black stem streaking is more likely to be salt-wind scorch or drought stress, especially in exposed gardens near the water.

   October is also when the summer's box tree moth pressure becomes most visible. Hedges with severe defoliation still have live stems under the damage and are usually recoverable; plants where bark has been stripped at the base by late-instar larvae need a more careful assessment.

   Don't feed box with a nitrogen-rich fertiliser in autumn. Soft new growth pushed on in October is vulnerable to the first frost and more susceptible to blight entry. Feed in spring with a balanced slow-release formulation, following the timing in our aftercare and feeding calendar.

6. November – December: winter care

   No trimming is needed once the hedge is dormant. If an overgrown or misshapen hedge needs renovation, wait until late February rather than cutting now. On heavy or poorly drained soil, the main winter risk for box is root suffocation from waterlogging rather than cold. A bark-chip mulch around the base, kept a few centimetres clear of the stems, improves drainage over time and reduces blight-promoting rain splash from bare soil onto lower foliage.

   Salt-laden wind after autumn storms can brown the windward face of box hedges in exposed gardens near the water. This is cosmetic and the plant grows through it in spring. Distinguish it from blight by the absence of black stem streaking: salt damage browns the leaf surface uniformly, blight attacks individual stems with characteristic dark discolouration at the base.

Box blight and box tree moth: how the cutting calendar connects to both

These two problems run through the same growing season. Box blight is worst in warm, humid conditions from May onwards. Box tree moth has at least two generations a year (RHS), with caterpillars active from spring into autumn. The cutting calendar above is partly built around both. Cut when conditions are dry, keep tools clean, remove all clippings, and check for caterpillar webbing before every cut. For a month-by-month guide to monitoring and managing both problems, see the hedge pest and disease calendar.

Box hedges and box topiary: the distinction matters

This guide covers box used as a linear hedge, low formal borders and boundary runs. If you have box shaped into balls, cones, spirals or other topiary forms, the broad cut timings are the same but the technique differs considerably, and the renovation logic for a three-dimensional shape is different again. The formal topiary maintenance calendar covers shaped-specimen work across Medway gardens.

Sources: Wildlife and Countryside Act 1981, section 1; Royal Horticultural Society guidance on Buxus sempervirens cultivation and box blight (Cylindrocladium buxicola); RHS guidance on box tree caterpillar (Cydalima perspectalis); Martin Fish, Pots & Trowels, box trimming technique and shaping (YouTube, UK).