Preparing Your Garden for a Cold Moorland Winter

Why Moorland Frosts Catch You Out

On high ground, the first proper frost can arrive a fortnight or more before it reaches the valley below. Cold air behaves like water: it drains downhill and pools in hollows, so the coldest spot on your plot is often not the exposed corner near the gate but the dip at the bottom of the garden, or the still pocket on the sheltered side of a hedge. That is worth walking round and noting now, while the ground is still soft and the leaves are only just turning.

Wind matters as much as temperature. A wet, driving wind off the moor will strip the leaves off a young shrub far faster than a still, colder night ever would, and it dries out evergreens that cannot take up water from frozen soil. Preparing for winter on an exposed site is really two jobs: protecting roots from the freeze-thaw cycle, and cutting down the wind's purchase on everything above ground.

Clear Water Away Before It Freezes

Water is the great destroyer of rural properties in winter, and it does most of its damage quietly. Once the leaves are down, clear the gutters and check every downpipe runs freely. A blocked downpipe that fills, freezes and splits is one of the most expensive oversights of the season, and it always happens on a night when you would rather not be up a ladder.

• Check the drain grate or soakaway at the foot of each downpipe is not silted up with leaves and grit.
• Lag outside taps with a foam jacket or a wrap of hessian and old feed sack. If the tap has an isolator inside, shut it off and leave the outside tap open to drain.
• Coil hosepipes and store them under cover. A hose left charged with water will split the first time it freezes hard.
• Water butts: secure the lid so it cannot blow off, and either drain the butt down or leave it part-full so ice has room to expand. If yours has cracked before in a hard winter, empty it and turn it upside down.

A split water butt in January is a nuisance. A split pipe inside a wall is a different order of problem altogether.

Mulch Thickly, but Keep It Off the Crowns

Mulching is the single best thing you can do for borders on an exposed site. It is not really about keeping plants warm; it is about holding the soil temperature steady. Repeated freezing and thawing heaves shallow-rooted plants clean out of the ground, and that kills more of them than the cold itself.

Wait until the soil is cold but not yet locked up hard, and mulch onto damp ground. A layer of 8–10cm of well-rotted manure, garden compost, bark or leaf mould is about right. Keep it back from the crowns of herbaceous perennials and clear of the stems of shrubs. A thick collar of mulch sitting against a crown holds water and rots it, and it gives mice and voles a warm, dry tunnel from which to gnaw bark all winter. Leave a gap of a few inches and let the crown breathe.

Tender things — dahlias, crocosmia, agapanthus, young phormiums — want either a much thicker blanket of dry material or lifting altogether. Tubers lifted and stored in barely damp compost in a shed will come through a moorland winter far better than anything left in the ground.

Tender Pots: Raise, Group, Wrap

Roots in a pot freeze far harder than roots in open ground, because there is no great mass of soil around them to buffer the cold. Terracotta and glazed pots also absorb water, and that water expands when it freezes, which is why so many lovely pots split in a hard winter.

• Stand every pot on feet, bricks or a slate so it drains freely, and take the saucers away so they cannot fill and freeze.
• Group pots together against a house wall on the sheltered side. The wall gives off a little warmth and deadens the wind, and the mass of grouped pots helps them all.
• Wrap the pot, not the plant, with bubble wrap or hessian tied with twine. Insulating the rootball is the point; smothering the foliage is not.
• Move anything genuinely tender into a cold greenhouse, a porch or an unheated shed. Avoid a warm room — the plants will break dormancy and then sulk for months.

Wind, Stakes and Winter Structure

Wind rock kills more young trees and shrubs on high ground than frost does, because it tears the new roots loose in wet soil. Check every stake and tie now, and loosen any tie that is beginning to bite into the bark — a tie that fits snugly in autumn will strangle a trunk by spring. Replace rotten stakes while the ground is still workable. After a gale, walk the plot and firm back in anything the wind has lifted, heeling it in and closing the gap at the roots with your boot.

Shake heavy snow off evergreens, hedges and conifers before it bends them out of shape, working upwards with a broom rather than knocking downwards. Check that cloches, cold frames, gates and fence posts are secure before the first storm rather than after it. Leave seedheads standing on perennials — they feed the birds, hold structure through the worst of the weather and look wonderful under frost. Resist pruning shrubs now; fresh cuts will not harden off and every wound is an open door.

The Last Few Jobs Before the First Frost

The forecast will give you a warning of the first hard night, so keep a short list ready and work through it in an afternoon. Lag the taps and drain the hoses. Clear the gutters. Mulch the borders. Move the pots into shelter. Check ties and stakes. Clear and secure the greenhouse, replacing cracked panes and checking that vents latch shut. Put a bucket of grit or sand by the door for the path, and top up the bird feeders — a well-fed garden is a livelier one, and the birds will repay you handsomely come spring.

Do all that, and the worst of the moorland winter will pass over a garden that is quietly sleeping rather than one you are patching up in February.