Creating a Wildlife-Friendly Garden Around Old Walls

Old Walls Are Habitats in Their Own Right

Before you plant a single climber or sow a single seed, it is worth looking at the wall itself as a habitat rather than a backdrop. A brick or stone boundary wall built with lime mortar is, in ecological terms, a small cliff. Its surface warms quickly in the morning sun, it sheds water slowly, and its pointing is full of the narrow crevices that solitary bees, mason wasps, spiders and over-wintering invertebrates need. A wall of any age may support dozens of lichen and moss species, and the sheltered side will be measurably warmer and drier than the open garden.

This matters because so much of what we do to old walls is well-intentioned housekeeping that quietly destroys that value. Repointing in hard cement traps moisture and forces it out through the bricks or stone, which then spall in frost; raking out every joint and filling it flush removes the nesting holes that masonry bees rely on; pressure washing strips lichen that took decades to establish; and a spring spray of biocide along the base wipes out the whole invertebrate community in an afternoon. If work is needed, insist on lime mortar matched to the original in mix and finish, and ask whoever does it to leave a proportion of open joints, particularly on south-facing elevations.

Climbers That Respect Historic Masonry

Climbers are the quickest way to knit a wall into the planting around it, and they add nesting cover, flowers for pollinators and autumn berries in one move. The trick is to choose plants that can be tied in rather than ones that attach themselves and force their way into the mortar. A tensioned stainless steel wire system on galvanised vine eyes, fixed discreetly into the mortar rather than the brick face, will carry almost anything and can be taken down if the wall is ever repointed.

• Honeysuckle (Lonicera periclymenum) — native, evening-scented, draws in moths; berries feed birds into autumn.
• Rambling roses — a single plant will cover several metres within a few seasons, flowers heavily in midsummer and then holds hips through winter.
• Common jasmine and star jasmine — good for a sheltered south or west wall; the scent carries in the evening.
• Late-flowering clematis — the viticella types can be cut hard in February and will not smother a small wall.
• Avoid vigorous self-clingers on fragile masonry. Ivy and Virginia creeper are superb for late bees, but they belong on a fence, a shed or a boundary hedge, not on soft historic brick.

Plant climbers around 45 centimetres out from the base of the wall, in a hole enriched with garden compost, and lean a cane back towards the wires so the stems travel naturally. Water generously for the first two summers; the rain shadow of any wall is deceptively dry.

Native Planting for Bees, Birds and Moths

The aim is a flowering season with no gaps, roughly from February to November. Group plants in generous drifts rather than scattering singles, so that a foraging bee can work a patch efficiently. Single, open flowers are far more useful than doubles, and native or near-native species generally support the widest range of insects.

• Earliest: hellebore, crocus, pussy willow, blackthorn.
• High summer: lavender, catmint, meadow salvia, thyme, foxglove, oxeye daisy, field scabious, betony.
• Late season: teasel, globe thistle, sedum, asters, ivy in a hedge nearby.
• Berries and hips: hawthorn, guelder rose, spindle, honeysuckle, roses.
• Seed heads for finches: teasel, nigella and any sunflower you can spare.

Keep a strip of long grass along the foot of the wall, mown once in late summer and once in spring, rather than strimmed flat. If you use any pest control at all, avoid slug pellets and residual insecticides; a garden that feeds birds and bats needs a functioning invertebrate population first.

Leave Some Corners Undisturbed

Orderliness is the enemy of wildlife. Set aside two or three corners that are not weeded, not cut back and not walked over, ideally one in shade and one in full sun.

• A log pile in damp shade, part-buried, for beetles, fungi and overwintering amphibians.
• Leaf litter left in place under shrubs as a foraging area for blackbirds and robins.
• A patch of bare, south-facing soil for mining bees, which nest in the ground.
• A heap of old stone and rubble, which slow worms and toads will use.
• A 13-centimetre gap under one boundary fence or gate, to keep a hedgehog route open.

Leave seed heads standing until late February or March, when the worst of the weather has passed, and always check long grass by hand before using a strimmer — hedgehogs and frogs sit tight rather than run.

Water, Shelter and the Legal Points

A small pond, even a buried half-barrel, transforms a garden. Give it gently sloping edges so hedgehogs and birds can drink safely, keep fish out, and leave one side open so bats can swoop low across the surface at dusk. A shallow dish of water with a few pebbles set in it will do the same job on a terrace.

For roosts and nests, site boxes three to five metres up on a south or west wall, away from windows and out of reach of cats. House sparrows and swifts will often use gaps under eaves and behind fascia boards if you resist sealing every last one.

Two legal points are worth knowing. Bats and their roosts are protected in law, so any work to a roof, eaves or wall where bats may roost should be assessed before it begins, and repairs are best done in spring or autumn. Nesting birds are also protected while a nest is in use, which is why hedge cutting is best left until late summer. On a listed building, planting itself is normally fine, but new fixtures, hard landscaping or anything that alters the fabric may need listed building consent, so a quick conversation with the conservation officer is always time well spent.

A Gentle Seasonal Rhythm

Work with the calendar rather than against it. Plant climbers and bulbs in October and November, when the soil is still warm. Prune roses and wisteria in winter, and leave anything that flowers on old wood until after midsummer. Deadhead sparingly — a few flowers left to set seed will feed goldfinches in January. Clean and check nest boxes in September, once the breeding season is properly over, and put out food and water consistently through the coldest months.

Old walls took centuries to acquire the cracks, lichens and warmth that make them so valuable to wildlife. Restoring them well and planting around them patiently is the same discipline: slow, observant, and generous with the untidy edges. The rewards come quietly — a bee working a sunny joint in March, a bat over the pond in July, a family of sparrows in the honeysuckle — but they come.