Autumn gardening

Autumn is the most important season in the garden year. The soil is still warm, autumn rain is reliable, and roots establish faster between September and November than at any other time. The bulbs you plant now flower next April. The hedge you put in this autumn will be twice the size of one planted next spring. The leaf mould you start now feeds the borders for years. Treated properly, autumn does the heavy lifting that makes the rest of the gardening year easier. This guide sets out the work that genuinely matters, in the order to do it, in a UK garden.

A few principles before the task list. Autumn in Surrey runs from late September through to the first proper frost (typically late October to mid-November). The most productive window for new planting is October, when soil temperatures are still high enough for root growth but rainfall is reliable. By contrast, much of the cutting-back work that used to define an ‘autumn tidy’ is now better delayed until late February or March, both for the plants and for the wildlife that overwinters in old stems and seedheads. The modern approach is to plant in autumn and tidy in spring.

The autumn planting window

The single most important autumn opportunity. Hardy trees, shrubs, hedging and perennials all establish better when planted in October and November than at any other time. The soil is still warm enough for roots to grow, rainfall is reliable, and the plant has a full winter and spring to settle in before the stresses of summer. Spring-planted equivalents struggle: they hit summer with shallow roots and need much more irrigation to survive.

• Bare-root and rootballed stock. The bare-root season runs roughly October to March. Bare-root plants are dug up while dormant and sold without soil; they establish quickly and cost a fraction of container-grown equivalents. Hedging (hornbeam, beech, yew, hawthorn), trees, roses and many fruit trees are all available bare-root. The single cheapest way to plant a serious hedge is in autumn from bare root.
• Hedging. Plant bare-root Carpinus betulus, Fagus sylvatica, Taxus baccata, Crataegus monogyna or Prunus lusitanica any time from late October to early March, weather permitting.
• Trees. Bare-root or container-grown specimens go in well from October. See our pleached trees guide for the dedicated bare-root pleached window.
• Hardy shrubs and perennials. Roses (particularly bare-root), Hydrangea, Viburnum, herbaceous perennials, ornamental grasses all go in well now.
• What to avoid planting in autumn. Tender or marginally hardy species (Cordyline, Trachycarpus, Fatsia in cold spots, half-hardy salvias) are better planted in spring once the worst of winter is past. Mediterranean dry-garden species (lavender, rosemary, cistus) prefer spring planting on heavy clay sites.

Spring bulb planting

Most spring-flowering bulbs go in between late September and the end of November. The exception is tulips, which prefer late November or even December planting: late planting reduces tulip fire (Botrytis tulipae), the fungal disease that affects bulbs planted too warm and too early.

• Planting depth. The rule of thumb is three times the height of the bulb. So a 50 mm Narcissus bulb goes 150 mm deep; a 30 mm crocus 90 mm deep. Too shallow and the bulb stresses in heat and frost; too deep and it may not flower.
• Narcissus (daffodils). Plant September to October. ‘Tete-a-tete’ (early dwarf), ‘Thalia’ (white, mid-season, AGM), ‘Cheerfulness’ (fragrant cream, mid) are reliable picks. Naturalise in lawns by planting in irregular drifts.
• Tulipa (tulips). Plant November to early December. ‘Queen of Night’ (near-black), ‘Spring Green’ (white-and-green viridiflora, AGM), ‘Ballerina’ (lily-flowered orange, fragrant, AGM). Treat most tulips as annuals on heavy clay; the showy hybrids rarely flower well in their second year.
• Allium ‘Purple Sensation’ and ‘Globemaster’. Plant October. Drumstick globes in May and June, perfect mid-season transition into summer.
• Crocus tommasinianus. Plant September to October. The best naturalising crocus for lawns; carpets of mauve in February. AGM.
• Galanthus nivalis (snowdrops). Best planted ‘in the green’ (as actively growing plants in March), but autumn-planted dry bulbs work too if soaked overnight first.
• Camassia leichtlinii. Plant October. Tall blue or white spikes in May, brilliant for naturalising in damp grass or wilder borders.
• Pot displays. The lasagne method (bulbs in layers in a pot: tulips deep, daffodils middle, crocus top) gives 12 weeks of continuous flower from February to May from one container.

Autumn lawn renovation

September is the prime month for lawn renovation. Soil is still warm enough for grass seed germination (typically 7 to 14 days), rainfall is reliable, and the lawn has time to thicken up before winter. The classic September sequence:

• Scarify. Remove the thatch (dead matted layer between living grass and soil) with a wire rake or powered scarifier. The lawn looks wrecked afterwards for two or three weeks. Normal and necessary.
• Aerate. Hollow-tine aeration relieves the compaction that London clay accumulates over a busy summer. Garden fork to 100 mm at 150 mm spacings is fine for small lawns; hire a hollow-tine machine for anything over 50 sq m.
• Top-dress. A 5 to 10 mm layer of sandy loam or fine compost, brushed in with a stiff broom to fill the aeration holes and level minor undulations.
• Overseed. 15 to 25 g/sq m over the whole lawn, more on bare patches. See our lawn seeding guide for the right mixtures.
• Autumn feed. An autumn-specific lawn feed (low nitrogen, higher potash and phosphate, typically around NPK 4-10-14) strengthens roots for winter rather than pushing soft top growth. Avoid spring or summer feeds in autumn; they encourage lush growth that is then vulnerable to frost and disease.
• Final mow heights. Raise the cutting height for the last few mows of autumn (40 to 50 mm rather than 25 mm). Longer grass goes into winter healthier.

Falling leaves: clear strategically, not obsessively

Fallen leaves are a resource, not a problem. Clear strategically where they matter; leave them where they help.

• Clear from lawns. Wet leaves left on a lawn block light, smother grass and encourage disease. A weekly rake or mower-with-grass-collector through October and November is standard.
• Clear from paths and patios. Wet leaves become slippery and break down into staining residue on porcelain, sandstone and decking.
• Clear from pond surfaces. Leaves rotting in a pond cause oxygen depletion. Net the pond surface during heavy leaf fall on overhanging trees.
• Leave in borders. A light layer of leaves in borders is beneficial: it acts as natural mulch, feeds the soil as it breaks down, and provides shelter for invertebrates and overwintering insects. Heavy accumulations should still be raked off.
• Leave a patch behind a shed or in a quiet corner. Hedgehogs, ground beetles and queen bumblebees overwinter under leaf litter. The single most useful thing a garden can do for hedgehogs is to leave one undisturbed corner from autumn through to April.

Making leaf mould

The most under-used resource in the garden year. Leaf mould is rotted-down deciduous leaves: dark, crumbly, low-nutrient, brilliant for soil conditioning, mulching and seed-sowing compost. It costs nothing, demands almost no work, and the only barrier is time. Two ways to make it:

• Wire bin. A simple wire-mesh enclosure (chicken wire stapled to four corner stakes is enough), 1 m square, filled with leaves and left. Useable after 18 to 24 months; fully rotted after 2 to 3 years. The slow option, but the result is excellent.
• Bin bags. Heavy-duty black bin bags filled with damp leaves, tied at the top, pierced with a few air holes and stashed behind the shed. Useable in 12 months. The fast option for small gardens.

Beech, oak and hornbeam leaves rot the best. Sweet chestnut, plane tree and evergreen leaves rot much more slowly; keep them separate or compost them differently. Pine needles take years and produce acidic leaf mould suitable for ericaceous plants only.

What NOT to cut back in autumn

The biggest shift in UK garden thinking in the last twenty years. The Victorian autumn-tidy convention has given way to leaving the bones of the border standing through winter, with the main cut-back work done in late February or early March. Why:

• Seedheads feed birds. Echinacea, Rudbeckia, Helenium, Eryngium, Hylotelephium, Verbena bonariensis all hold seed that finches and tits feed on through winter.
• Hollow stems shelter invertebrates. Ladybirds, lacewings and solitary bees overwinter in hollow perennial stems. Cut everything to the ground in October and you remove their shelter.
• Seedheads and grass plumes give winter structure. Miscanthus sinensis, Calamagrostis × acutiflora ‘Karl Foerster’, Panicum virgatum, Stipa gigantea all look beautiful through frost and low winter light. The new-perennial gardens at Wisley and Pensthorpe are designed specifically for the winter structural display.
• Old foliage protects crowns. The dead top growth of marginally hardy plants (Penstemon, Salvia greggii, Agastache) protects the crown from frost. Cut these back in April, not October.

What you can usefully cut back in autumn: anything that has flopped onto a path, anything diseased, and the foliage of Hemerocallis and Hosta (which collapses into mush by November anyway). For everything else, wait until late February. See our spring garden tidy guide for the proper cut-back timing.

Protecting tender plants

• Dahlias. In our area (Surrey, milder winters than further north), most Dahlia tubers can be left in the ground with a thick mulch (150 to 200 mm of bark or straw) after the first frost has blackened the foliage. In colder gardens or on heavy waterlogged clay, lift, dry and store in a frost-free shed in dry compost. See our dahlias guide.
• Cannas, gladioli and other tender bulbs. Lift after first frost, dry off, store in dry compost in a frost-free shed.
• Tree ferns and tender exotics. Crown of Dicksonia antarctica stuffed with dry straw and bracken, fronds tied up over the crown, the trunk wrapped in horticultural fleece. Banana plants (Musa basjoo) cut down to about 1 m, wrapped in chicken wire and stuffed with straw.
• Pots and containers. Move into the lee of the house, raise off the ground on pot feet (so drainage works and frost cannot crack the base), wrap large terracotta pots in hessian or bubble wrap for true cold snaps. Empty unglazed terracotta pots that you cannot move; freezing waterlogged terracotta cracks every winter.
• Tender succulents and citrus. Bring under cover or into a frost-free greenhouse for the winter. Aeonium and Echeveria in particular do not survive an unprotected UK winter.

Other autumn tasks worth doing

• Lift and divide overcrowded perennials. Hemerocallis, Hosta, Geranium, Astilbe, ornamental grasses (cool-season species like Stipa and Festuca) all divide well in early autumn while the soil is still warm. Replant the divisions immediately or pot up for spring planting.
• Plant garlic. Late October to early November is the right window. Garlic needs a cold spell to develop properly; spring-planted garlic doesn’t form proper bulbs.
• Sow hardy annuals. Direct-sown Calendula, Nigella, cornflowers, poppies sown in September flower three weeks earlier than spring sowings the following year, and produce sturdier plants.
• Clean and store tools. Wash secateurs and loppers, sharpen blades, oil moving parts. A small amount of oil on the wooden handles of forks and spades extends their life significantly. Mower: drain fuel, clean the deck, sharpen the blade before storage.
• Empty rain barrels. An ice-blocked downpipe in January causes far more damage than a temporarily-empty water butt. Drain, clean and reposition.
• Winterise irrigation. Drain irrigation lines, blow out compressed air through outdoor pipework, lag exposed taps. A burst pipe in February is an avoidable winter cost.
• Insulate outdoor taps. Foam pipe lagging or a purpose-made tap cover prevents the most common frost-damage call-out.

Enjoy the autumn colour while it lasts

The reward for all the work. UK gardens deliver some of the most spectacular autumn colour anywhere outside New England, and the second half of October through early November is the moment. The plants worth growing for autumn drama include:

• Trees. Acer palmatum (Japanese maple), Liquidambar styraciflua ‘Worplesdon’, Parrotia persica (Persian ironwood), Cornus kousa, Cercidiphyllum japonicum (with its caramel scent on warm autumn days).
• Shrubs. Euonymus alatus (winged spindle), Hamamelis × intermedia (witch hazel, with golden autumn foliage and winter flowers), Hydrangea quercifolia (oak-leaved hydrangea).
• Climbers. Parthenocissus tricuspidata (Boston ivy), Vitis coignetiae (ornamental vine).
• Perennials and grasses. Miscanthus sinensis in plumed seedhead form, Panicum virgatum turning amber and purple, the late Aster family (now Symphyotrichum), Hylotelephium ‘Autumn Joy’.

What to avoid in autumn

• Cutting everything back to the ground. The old Victorian approach. Costs the garden its winter structure and the wildlife its food and shelter. Leave seedheads and grasses standing.
• Planting tulips in September. Too warm, risk of tulip fire. Wait for November or December.
• Planting Mediterranean species on cold wet clay. Lavender, rosemary and cistus prefer spring planting in our soil; autumn-planted specimens often rot in waterlogged winters.
• Heavy lawn feeding in autumn. Use an autumn-specific feed (low N, higher K and P) or none at all. Spring or summer feeds push soft top growth that frost will damage.
• Hedge-cutting in September. Bird-nesting season runs to 31 August under the Wildlife and Countryside Act 1981; from September a careful cut is permissible, but it’s also late enough that any vigorous late-summer growth flushes have already happened. Better to wait until late winter (February) for the main shape.
• Burning fallen leaves. Banned in many urban areas, environmentally wasteful, and you’re burning a year’s supply of free leaf mould.

Frequently asked questions

When should I plant spring bulbs?

Most spring-flowering bulbs go in between late September and the end of November in Surrey. Daffodils, alliums, crocuses, hyacinths and snowdrops can all go in from late September. The exception is tulips, which prefer November or even early December: late planting reduces the risk of tulip fire (Botrytis tulipae), the fungal disease that affects bulbs planted into still-warm soil. Plant bulbs at three times their height in depth, in well-drained soil.

Should I cut my perennials back in autumn?

For most herbaceous perennials, no. The modern UK garden convention is to leave seedheads and stems standing through winter and cut back in late February or early March. Seedheads feed birds, hollow stems shelter overwintering insects, and the dead top growth of marginally hardy plants (Penstemon, Salvia greggii, Agastache) protects the crown from frost. The exceptions are plants that collapse into mush (Hosta, Hemerocallis), anything diseased, and plants that have flopped onto paths. Otherwise wait until spring.

What is the best time of year to plant a new hedge?

October to early March, with bare-root stock. Bare-root hedging plants are dug up while dormant, sold without soil, and establish significantly faster than container-grown equivalents. They also cost a fraction of the price. The standard UK hedging species (hornbeam, beech, yew, hawthorn, blackthorn, native mixed) are all available bare-root through this window. Plant into a single trench with the roots well spread, water in well, and stake or guard against rabbits and deer where present.

How do I make leaf mould?

Two methods: a wire-mesh enclosure (1 m square is plenty for most gardens) filled with damp leaves and left for 18 to 24 months, or heavy-duty bin bags filled with damp leaves, tied, pierced for air and stashed behind the shed for 12 months. Beech, oak and hornbeam leaves rot the best; sweet chestnut, plane tree and evergreens rot much more slowly. The finished leaf mould is dark, crumbly, low-nutrient and brilliant for mulching, soil conditioning and seed-sowing compost. It costs nothing and demands almost no work.

Should I lift my dahlia tubers for winter?

In Surrey, most dahlia tubers survive winter in the ground with a thick mulch (150 to 200 mm of bark or straw) applied after the first frost has blackened the foliage. Our milder London-influenced winters and well-drained sites usually allow this. In colder gardens, on heavy waterlogged clay, or in particularly exposed positions, lift tubers after the first frost, dry them off for a few days, and store in dry compost in a frost-free shed or garage. Either approach works; the in-ground option is significantly less work.

When should I do my autumn lawn renovation?

September is the prime month, with the work ideally completed before the end of the month. Soil temperatures are still high enough for grass seed germination (typically 7 to 14 days), rainfall is reliable, and the lawn has time to thicken up before winter. The classic sequence is scarify, aerate, top-dress with sandy loam, overseed at 15 to 25 g/sq m, and apply an autumn-specific feed (low nitrogen, higher potash, around NPK 4-10-14). Avoid summer or spring lawn feeds in autumn; they encourage soft growth that frost will damage.

Let’s get your garden ready for next year

If you would like the autumn work done properly by an experienced team (planting, bulbs, lawn renovation, leaf clearing, tender-plant protection), we’d be glad to help. Flourish Landscaping carries out seasonal maintenance and autumn planting across Kingston, Surbiton, Richmond, Esher and the wider Surrey area. See our garden maintenance service for one-off seasonal jobs and annual care contracts.

Contact us to arrange a consultation and book the autumn work.