Autumn Tree Care Tasks for a Healthy Garden

Why Autumn Is the Tree Keeper's Busiest Season

As the clocks go back and the first gales roll in off the Atlantic, our trees begin the quiet work of shutting down for winter. Leaves change colour, sap retreats, and growth slows to a near standstill. For the gardener, that pause is a gift: the tree is dormant enough to tolerate work, yet the soil is still warm enough to help it recover. Everything you do between October and December will shape how your garden looks next spring.

The trick is to work with the season rather than against it. Rushing about with a saw in wet weather does more harm than good; leaving a thick mat of soggy leaves on a lawn for three months does the same. Below are the jobs that matter most, in roughly the order they should be tackled.

Clear Fallen Leaves — But Don't Waste Them

Leaves are not rubbish. They are next year's soil, and a lawn smothered by a wet layer of them will yellow, weaken and grow moss. Clear paths, lawns and any low-growing plants first, because a dense blanket excludes light and traps moisture against foliage.

Rather than bagging everything for the council, turn the bulk of it into leaf mould:

• Collect leaves with a lawnmower on a dry day — shredding them speeds decomposition dramatically.
• Fill old compost bags or a simple wire ring, dampen the contents, and tie or cover loosely.
• Leave for twelve months for a coarse mulch, or two years for a fine, crumbly seed-sowing compost.
• Keep a separate pile for tough leaves such as oak, beech and horse chestnut, which take longer than birch or lime.

Don't put leaves carrying obvious disease — black spot on roses, or heavy tar-spot on sycamore — into the leaf-mould bin. Bin those instead, or burn them if local rules allow.

Mulch the Root Zone Before the Frosts

Once the ground is cleared, spread a generous mulch over the roots of trees and shrubs. A layer of well-rotted manure, garden compost or your own leaf mould, roughly 5–8cm deep, insulates the soil, suppresses weeds and feeds the soil life that keeps roots healthy.

Two rules matter here. First, never pile mulch against the trunk — a mound around the base encourages rot, bark damage and, in time, disease. Leave a clear gap of 10–15cm so the flare where trunk meets root stays dry and visible. Second, extend the mulch out to the drip line, or as far as you reasonably can. Tree roots spread far wider than most people imagine, often two or three times the height of the canopy.

If your soil is heavy clay and waterlogged, fork over the surface gently first to break any pan, then mulch. On light, sandy ground, mulch thickly — it holds moisture and nutrients that would otherwise wash straight through.

Inspect Trees for Damage and Weak Points

With the leaves gone, you can finally see the skeleton of your trees. Walk the garden after a dry spell and look up — this is the single most valuable half hour you will spend all autumn.

Check for:

• Cracks and splits in trunks or main limbs, especially where a fork forms a tight V-shape.
• Fungal brackets or shelf-like growths on the trunk, which often signal internal decay.
• Deadwood — brittle, barkless branches that will drop in the first storm.
• Loose bark, oozing wounds or hollows at the base.
• Rubbing branches crossing each other and wearing away bark.

Small deadwood can be removed yourself with a clean, sharp pruning saw. Anything larger than your wrist, anything high up, or any tree showing significant decay should be assessed by a qualified arboriculturist with the right insurance and climbing kit. Storm-damaged limbs are unpredictable, and a chainsaw at height is not a DIY job.

Prune Wisely — and Know What to Leave Alone

Autumn and early winter are ideal for removing dead, damaged or diseased branches, and for shaping young trees while you can still see their structure. Make clean cuts just outside the branch collar — the slight swelling where the branch joins the trunk — and never leave a long stub. Avoid painting wounds; trees seal themselves better without it.

But there is a firm exception. Do not prune plums, cherries and other Prunus species in autumn or winter. Fresh cuts at this time are an open door for silver leaf and bacterial canker. Prune them instead in late June or July, when spores are least active and wounds heal quickly. Likewise, leave birches, maples and walnuts alone in autumn if you can — they bleed sap heavily when cut in late winter and early spring. Better to prune them in midsummer.

Plant, Stake and Protect Young Trees

November to March is bare-root planting season, and it is by far the cheapest and most reliable way to establish new trees. Order whips and standards from a reputable nursery, keep the roots damp, and plant into a square hole slightly wider than the root spread. Firm the soil in layers, water well, and mulch as above.

Young trees need protection through their first winters:

• Check and loosen tree ties so they don't strangle a swelling trunk.
• Replace broken stakes; a tree should flex slightly, not stand rigid.
• Fit spiral guards or mesh against rabbits and deer, especially in rural gardens.
• Water evergreens and newly planted trees during any dry, mild spells right through winter.

Do these jobs now, while the soil is workable and the weather is merely brisk rather than brutal, and your trees will reward you with stronger growth, cleaner structure and far fewer problems when spring arrives.