Unless you live down a dingly dell in the depths of the countryside, it is increasingly difficult to sit in peace in your garden these days, what with the cacophony of car alarms and police sirens. Even country folk have to contend with the incessant roar of motorways or the sound of boy racers haring down the lanes. Not to mention the buzzing of lawn mowers or the tinkling of wind chimes.
Unlike light waves, which travel in straight lines, sound waves can bend around obstacles. But there are still tricks you can employ to turn down the volume - and that doesn't just mean putting up a brick wall.
Green barriers: Plants can create a sense of privacy and reduce unwanted noise. A physical barrier of lush growth may not significantly reduce the noise, but it will create a microcosm within which there is a restful atmosphere. The deeper the planting, the better. If space is tight, a slim wall of plants such as bamboo will have a beneficial psychological effect. Leaves - especially large ones - are also good at filtering pollution, as dust particles will settle on them.
Yew, holly and Thuja plicata 'Atrovirens', which has dark-green leaves, are time-honoured candidates for hedging and are used to filter out noise because of their dense foliage.
Rhododendrons are also good; if you have chalky soil rather than the acid they need, the long, pendulous leaves of Viburnum rhytidophyllum will do the same job. A wall can be covered with a thick, fleshy-leaved evergreen climber, such as Clematis armandii, or variegated ivy, which will also reduce volume levels.
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Trees: The larger a leaf, the better it is for breaking up sound waves. One of the strengths of the plane and lime trees you see in urban spaces is their big leaves, and they can be trained into pleached (raised) hedges to make a more dense planting. Although not the most imaginative choices, Norway maples and sycamores, with their flat, horizontal foliage, grow fast and will do the job. Poplar and mountain ash are also useful. As the poplar is a fast grower, it should be positioned with care. Don't plant too near the house, as the roots will seek out water and may damage foundations.
If you are in a hurry, Paulownia tomentosa is a fast-growing tree. The trick is to keep it pollarded, so it puts its energy into creating leaves that can grow to 18in or more in diameter. The large, elegant leaves of the tree of heaven, Ailanthus altissima, also make it an effective choice. This tree can be clipped to increase the foliage.
All the trees above are deciduous. If you want a good evergreen, then Quercus ilex, the evergreen oak, makes a fine dome-shaped tree. You can keep it within bounds without spoiling its shape through clipping.
Earth mounds: As anyone who has ever walked to the other side of a hill knows, soil is a great sound buffer - even an earthwork of 3ft-5ft can have an effect. Introducing a hill into the garden might not be a practical option for readers without the room for a Capability Brown landscape, but you should consider making a bund, or a bank of soil.
Next time you pass a Travelodge on a motorway, note that they normally have raised banks strategically placed to reduce the effects of the traffic hum on the accommodation. For a more elegant example, look at Great Fosters hotel, in Surrey, where the landscape architect Kim Wilkie has created a 20ft-high earthwork behind a landscaped grassy amphitheatre. It filters out the noise of the M25 on the other side so effectively that concerts can be held there.
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Trees planted on top filter noise as well. The art lies in creating the illusion that the bank has grown out of the landscape; the last thing you want is lots of humps and bumps. Gently sloping sides and a variety of trees and shrubs on top can do this.
As the bank will need quite careful construction - you'll have drainage and substrate to consider, as well as the angles of the slopes - it is best to call in a landscaping contractor to make it for you. Ask at your garden centre or look in the local newspaper for ones in your area.
Diversionary tactics: if you can't beat the noise, create your own more gentle sounds on which to concentrate. Running water - even a fountain - in your garden masks the noise of traffic and aeroplanes by focusing the ear nearer to home. You don't need much space - even a little bubble pool with a (quiet) pump will do the job. Crocus, for example, has a set of dark terrazzo balls with water cascading over their surface for £300 (www.crocus.co.uk).
Just make sure that your own water feature isn't driving the neighbours mad. After all, one man's relaxing sound of tinkling water over pebbles could be another's irritating noise pollution.