Why late winter is the kindest time to prune evergreens

Late winter, from mid-February to early March, is a sweet spot for many hardy evergreens in the UK. The plant is still dormant, or just beginning to stir, so pruning causes far less stress than a summer cut. Sap is not rising strongly, and the risk of bleeding — where a wound weeps and weakens the plant — is lower than in spring. Fungal spores are also less active, giving clean cuts a better chance to seal. Best of all, the bare bones of the shrub are visible, so you can see the true shape without a mask of new growth. Choose a mild, dry day when the wood is not frozen and no hard frost is forecast for the next few days.

Start with the three Ds: dead, damaged and diseased

Before you think about shaping, remove what the plant no longer needs. Work through the evergreen methodically and take out the three Ds first:

• Dead wood — brittle, dull, and no green layer when you scratch the bark with a fingernail. Cut it back to healthy tissue, following the branch to a strong side shoot or bud.
• Damaged stems — snapped by wind, snow or clumsy footwork. Trim to a clean edge, not a torn end.
• Diseased growth — cut well below the visible infection, and sterilise your tools between cuts with methylated spirits or a diluted household disinfectant.

Bag the prunings rather than adding them to the compost heap. This first pass alone can transform a congested shrub and often removes the need for harsher cutting later.

Know what your evergreen can take

Not all evergreens respond to pruning in the same way, and the difference matters. Conifers such as pine, spruce and fir rarely regrow from old, bare wood. They keep their needles on the outer shell, and if you cut back into the brown, leafless zone, that branch will usually stay bare for good. Instead, trim only the green tips, or snap out the growing "candles" in late spring. Yew, thuja and leylandii are more forgiving and can push new shoots from older wood, though regrowth is slow. Broadleaf evergreens are a mixed bunch too. Box, holly, laurel and photinia generally tolerate a decent cut and will send out fresh growth. Rhododendrons, camellias and pieris form their flower buds in late summer or autumn, so pruning them now means sacrificing this year's blooms. If flowers matter more than shape, wait until immediately after flowering.

Make clean cuts and respect the bare-wood rule

Sharp tools make all the difference. Bypass secateurs for stems up to a centimetre or so, loppers for thicker branches, and a pruning saw for anything woody. Never use anvil secateurs on green stems: they crush rather than slice. Make each cut just above a healthy bud or side shoot, angled slightly away from it, leaving no stub. A stub dies back and lets disease in; cutting too close damages the bud. The bare-wood rule is simple: if there are no leaves, needles or visible buds at the point you are cutting back to, the branch may not regrow. This is especially true for conifers. When in doubt, cut less. You can always take off more next year, but you cannot put it back. For hedges, a light trim that stays within the green growth is far safer than a hard renovation cut.

Shape lightly for structure and airflow

Once the dead and damaged wood is gone, step back and look at the plant from several angles. The aim is a natural, open shape that lets light and air into the centre, not a tight ball that blocks both. Thin out crowded branches, remove any that cross or rub together, and shorten overly long shoots by no more than a third to a half. Cut back to an outward-facing bud or shoot so new growth grows away from the centre. On a large evergreen, never remove more than about a quarter of the total canopy in one year. Work slowly, stepping back after every few cuts. It is easy to get carried away with secateurs in hand, but evergreens are patient growers. A gentle, well-judged prune looks better and keeps the plant healthier than a severe chop.

Aftercare and what to leave until later

After pruning, tidy up and give the plant a little care. A mulch of well-rotted garden compost or bark around the base — kept clear of the trunk — helps retain moisture and suppress weeds. Water if the soil is dry, especially for evergreens in containers, but do not feed until you see new growth in spring. Clean and oil your tools before putting them away. If a hard frost is forecast, delay pruning until it passes. Leave tender evergreens, such as rosemary or olive, until late spring when the risk of cold damage is over. And if your evergreen flowers on old wood, put the secateurs down now and wait for the blooms to fade. Pruning is a conversation with the plant, not a one-off task. Little and often, at the right time, will keep your evergreens thriving for decades.