Akin to the moat around your castle, the structures that mark the perimeters of your garden play an important role. As well as acting as territorial divides with neighbours, they can boost or reduce security, sound, wind, pollution, and biodiversity, and have a huge impact on the look and feel of an outdoor space. These boundaries might be hard landscaping barriers, such as fencing, trellis, or walls, or living structures: willow, bamboo, or hedging. Each has advantages and disadvantages, which help to decide which type to go for.
What is the best garden boundary?
A hedge takes time to establish and will need regular clipping, but it's well worth it. As well as adding more de-stressing greenery to the garden, hedging is by far the best boundary for wildlife, offering shelter, nesting sites, and food. It also reduces sound, wind, pollution, and salt (in coastal gardens) by catching them through the natural filtering system of its leaves. Ideally, plant your hedge in autumn, when bare-root hedging bundles are available: as well as being low cost, bare-root plants will establish faster. There is a wide range of plants to choose from and the modern approach is to combine them to form a tapestry hedge: a mix of different deciduous and evergreen plants clipped into one boundary to provide food for wildlife and visual interest in every season; if disease hits, you lose one or two plants, rather than the whole boundary, as would be the case with a mono-hedge.
*Small-leaved plants, such as long-lived yew (Taxus baccata), are superb for filtering (and thus reducing) sound and wind, and they clip beautifully.
*Plants with hairy foliage catch salt and pollutants well. For instance, research by the RHS found that the small, downy leaves of Cotoneaster franchetii make it 20% more effective than other plants at shielding us from traffic fumes; it's also a fabulous wildlife plant, roaring with bees when it flowers in early summer and laden with berries for birds in autumn.
*A combination of evergreen and deciduous plants can reduce flooding risk. The RHS found that a mixed hedge of Thuja (an evergreen conifer) and hawthorn minimised damage from heavy rainfall.
*Spiky plants deter burglars and protect birds from predators. Good choices include hawthorn, firethorn, Rosa rugosa, and holly, all of which provide food for bees and birds.
*Colourful leaves add to the wonderful tapestry effect of a clipped mixed hedge. For example, copper beech is wine-purple in summer, before turning amber brown and remaining on the plant throughout winter; whilst good old field maple (Acer campestre) blazes golden yellow in autumn.
*Avoid thuggish plants (such as Leyland cypress) that grow too high and don't clip well. Neighbours are legally allowed to complain about anything that blocks their sunlight over 2 metres.
Halfway between a hedge and a fence, a 'fedge' is a living boundary – usually made of willow – that offers a refreshing alternative to both. Be careful which type of willow you choose because they grow to different heights: Salix viminalis, for instance, is robust and tall and can be used as a windbreak, while S. purpurea 'Elegantissima' is colourful and pretty but not as vigorous; both offer catkins for wildlife. Eventual height is not as much of an issue as it is with bamboo, however, as willow responds well to pruning.
Available in a wide range of styles, every fence is not made equal. The widely available flimsy timber lap panels are cheap, but often look unattractive, don't allow wildlife access, and easily blow down in strong wind; horizontal hit-and-miss fencing (using wide boards) is best avoided as it's easy for burglars to climb; and close-board fencing is a bad idea in an exposed site because it doesn't filter wind. Fence panels with horizontal narrow slats that have slim gaps between them look elegant and filter wind, making them a great choice; softwood should be treated regularly, but hardwood (although more expensive) offers better endurance.
Good quality hardwood trellis panels make an excellent boundary. Join them with something secure, such as solid posts concreted into the ground. When painted blue or green, they recede well, creating a sense of peace and space, and, of course, they can be clad with a huge range of climbing plants, including roses, which provide security via their thorns, and wildlife must-haves, such as ivy and honeysuckle, both of which thrive in part shade.
A walled garden is romantic, private, and creates a warm microclimate that allows a wider range of plants to be grown.
*Stone walls can be pricey, but, when constructed well, last a long time; they also weather beautifully. Reclaimed stone is often characterful, while local new stone blends in well to your area and is more sustainable: for instance, Sussex flint or Cornish granite. Portholes could be built in to frame views in the distance, if you have them. To reduce costs, bricks or concrete blocks can be clad with a stone veneer.
*Dry-stone walls are an excellent choice, being wildlife friendly and having a more natural look, which suits the contemporary garden. They can be built with varying degrees of spacing between the stones, which should be discussed with your waller; for instance, occasional wider gaps (in the style of a field wall) could be left for birds to nest in and – at the base – for hedgehogs to amble through; but even slim gaps will provide habitat for insects and lizards, as well as filtering wind and sound. If you have children who may climb on the wall, it's worth adding at least some areas of mortar to the wall to secure it, especially on the top.
*Brick walls are usually much cheaper than stone; select well-fired bricks to prevent damp, and choose a vernacular brick colour so the garden blends well into your surrounds. Glass bricks are another option to let light flood in.
*Concrete walls – usually constructed from concrete blocks, then rendered and painted – are cheap and strong and could contain glass bricks or panels to brighten the garden. Concrete walls are an excellent way to add colour to an outdoor space, with one of the most striking examples being the pink fair-faced concrete walls of Mexican architect Luis Barragán. Their downside is they will need repainting every few years and don't allow wildlife access, unless you ask your builders to create a hole at the bottom.
*Gabion baskets can be less expensive than many wall options and filter wind well. There's also the advantage of being able to put rubble from building work into them, perhaps disguised with more attractive stone or pebbles on the surface or with Sedum to create a green wall.
*Prevent problems to ensure a wall's longevity and to protect the house, if it abuts it. Various damp-proofing materials could be installed under and atop the wall to guard against damp. Because the wind can't move through solid walls, they require strengthening at intervals – for example, via piers or internal reinforcement. And expansion joints allow for movement (rather than cracking) when temperatures fluctuate.
Attempting to slot your garden into its surrounds is yet another way to decide what type of boundary to erect. In Japanese design, the principal of 'borrowed scenery' (shakkei) dictates how a boundary is chosen because the perimeter must allow the countryside beyond to appear to be part of the garden. This makes the garden look seamless and, in turn, it feels more spacious. At the least, following the rule of shakkei, the perimeter structures ought, in some way, to echo their surrounds, so that the eye isn't overly drawn to them. For instance, if your garden abuts deciduous woodland or your neighbours' have deciduous trees in their gardens, a hedge of hornbeam or beech would mimic the green summer tones of the leaves, followed by an echo of their autumn colours. If you're lucky enough to live in the Cotswolds or the Lake District, a dry-stone wall would blend into those landscapes, where dry walls are an iconic feature. And the same rule could be as simple as choosing iron fencing or red-brick walls, if those materials are a feature of the street you live on.
Bamboo makes an attractive, lush green boundary, either left as it is or clipped into a hedge for more structure. It can form a dense screen, creating privacy and reducing noise and pollutants, but still allowing wildlife through; it also rustles beautifully on the wind, and evergreen forms provide colour all year. It's very important to select a clumping (non-spreading) type of bamboo, such as Fargesia, because forms that run can create as much havoc as Japanese knotweed. It's also a good idea to opt for one that grows to the height you want your hedge because although bamboos can be trimmed into shape, they can look a bit odd afterwards. To force the plants to grow sideways, you could also install a barrier. Fargesia rufa (2.5m) and F. robusta (5m) are both excellent.
