Autumn Pruning Guide for Shrubs and Trees

Start With What Autumn Is Really For

Autumn is a busy time in the garden, but it is not a season for hacking everything back to ground level. The shortening days and cooling soil are telling your plants to slow down and harden off before winter, and every cut you make is an invitation for new growth that simply will not have time to toughen up. That fresh, sappy regrowth is the first thing a sharp frost will scorch.

What autumn is genuinely excellent for is tidying up, removing dead and damaged material, giving certain shrubs a light shape-up, and tackling a handful of jobs that are genuinely best done now. Get those right and your plants will come through winter cleaner, less prone to windrock, and ready to burst away in spring.

The Three Ds: Dead, Damaged and Diseased

Whatever else you do this month, deal with the three Ds first. This material can be removed at any time of year, on almost any plant, with no risk to the plant's shape or flowering.

• Dead wood — cut back to healthy wood. Look for a green, creamy or white core on the cut surface. Brown, hollow or brittle wood is dead; keep going until you find live tissue, pruning back to a strong bud or a side branch.
• Damaged wood — snapped branches, cracked limbs from summer storms, bark torn by wind. Cut cleanly below the damage rather than leaving a ragged stub.
• Diseased wood — canker on apples and roses, blackspot-ridden stems, coral spot on dead branches. Cut back into clean wood and clean your blades with methylated spirits between plants so you do not carry the problem around the garden.

Do this job on a dry day and take the debris straight to the green waste or burn it — do not add diseased material to the compost heap.

Shrubs to Prune Now — and Those to Leave Alone

A useful rule: if it flowers on wood it made this year, light autumn work is fine. If it flowers on last year's growth, hands off until after flowering.

Safe to tidy or thin lightly in autumn:

• Cornus (dogwood) grown for winter stems — you can thin overcrowded old stems now, though the hard coppice is best left until March.
• Buddleja davidii — shorten long, whippy stems by about a third so they are not ripped out by winter gales. The proper hard prune waits until March, when you cut back to a low framework.
• Wisteria — shorten those long, trailing summer whips back to about five or six buds from the main framework. This is one of the most valuable autumn jobs you can do.
• Tired-looking roses — take out crossing stems and reduce tall growth by roughly a third to prevent windrock. The real prune happens in late February or March.

Leave well alone until spring: hydrangea macrophylla (lacecaps and mopheads flower on old wood), lavender and rosemary (never cut into old, leafless wood, and never in autumn), hardy fuchsias and penstemons (their top growth protects the crown through frost), and anything marginally hardy such as cistus or ceanothus, which resent autumn pruning badly.

Trees: Timing Is Everything

Most ornamental and fruit trees are pruned in winter while dormant, but a few need careful handling. Avoid pruning plums, cherries and other Prunus between October and spring — the open wounds are an easy route in for silver leaf fungus. If a branch must come off, do it in June or July instead.

Birches, acers and walnuts bleed heavily if cut in late winter and early spring, so late summer or early autumn is the practical window if a branch has to go. Even then, keep cuts to a minimum and never lop a limb off a Japanese maple just for tidiness.

Apples and pears can be tidied lightly now, removing dead wood, rubbing branches and any fruit left hanging, but the formative and renewal pruning is a winter job. In exposed or frosty gardens, wait until the worst of the cold has passed. If you have a magnolia, it is pruned straight after flowering in midsummer, not now.

Making a Cut That Heals Well

Good technique matters more in autumn than at any other time, because the plant's own sealing process slows as temperatures drop. A few principles cover almost everything:

• Cut just above a healthy outward-facing bud, roughly 2–3mm clear, with the slope angled away from the bud so water runs off.
• When removing a whole branch, cut back to the branch collar — the slight swelling where it joins the trunk. Do not leave a stub and do not cut flush.
• For anything over about 4cm across, make a three-part cut: an undercut, a top cut slightly further out, then a final clean cut to the collar. This stops the branch tearing and stripping bark down the trunk.
• Use sharp, clean bypass secateurs and loppers. Blunt blades crush tissue and leave a wound that frost and fungus will find.
• Skip the wound paints. Modern advice is to leave the cut to seal naturally.

Work on a dry, mild day — ideally above about 5°C — and stop if hard frost is forecast within a few days. Frozen wood is brittle, and freshly exposed tissue is vulnerable.

Clear Up, Mulch and Let the Wildlife Settle

Once the pruning is done, gather up the cuttings. Shredded healthy material makes a decent mulch or compost ingredient; anything diseased goes elsewhere. A generous layer of well-rotted compost or bark mulch around the base of your shrubs — kept clear of the stems themselves — insulates the roots and feeds the soil through winter.

Finally, resist the urge to make everything immaculate. Seedheads on teasels, sedums and grasses feed the birds, and a few undisturbed leaf piles give hedgehogs and insects somewhere to shelter. Prune what needs pruning, tidy with purpose, then put your feet up and let the garden settle into its own quiet season.