A dense, thorny boundary can make a garden harder to enter without a single camera, and the Royal Horticultural Society (RHS) publishes practical advice on using planting for security. A tall hedge can also become a dispute with a neighbour, and in England the council has powers over evergreen hedges above two metres. This article summarises the RHS page “Garden Security Tips to Prevent Theft” and the government guide “High hedges: complaining to the council”, and it treats them together because a security hedge that grows too tall can become a complaint. Part 8 of the Anti-social Behaviour Act 2003, which the guide explains, is shown on legislation.gov.uk as extending to England and Wales, and this article does not cover Scotland or Northern Ireland. It is general information, not legal advice.
What the RHS suggests for boundaries
The RHS says the first line of defence against garden theft is secure boundaries, particularly at the rear, where people are often less watchful. It says any measures must be reasonable in law and warns against barbed wire or other materials that could seriously injure an intruder, because an injured intruder may take legal action against the homeowner. The site’s guide to booby traps and DIY deterrents covers that legal point in more detail.
On fences, the RHS says they should be of solid construction and that planning permission may be needed for fences over 2 metres, so the local planning office should be asked. It suggests fixing 30 to 45 centimetres of trellis to the top of a 1.8-metre fence, because trellis will not support a person’s weight and the noise of it breaking is a deterrent. It also suggests growing thorny climbers such as roses up fences. In front gardens the RHS prefers low walls and fences of no more than 1 metre, which do not screen intruders from view, and it advises pruning overhanging branches and foliage from around windows and doors to keep the view clear. The site’s piece on front fences, walls and gates explains the height limits.
Thorny hedges
The RHS says hedges can make a very good barrier, that most conifers form a thick hedge that is difficult to get through and that thorny shrubs are the most effective. It lists these thorny plants as making a medium to large hedge of 80 centimetres to 1.8 metres:
- barberry (Berberis × stenophylla);
- hawthorn (Crataegus monogyna);
- holly (Ilex aquifolium);
- firethorn (Pyracantha);
- Scotch briar (Rosa spinosissima); and
- blackthorn (Prunus spinosa).
It adds that low-growing thorny shrubs can be planted at the base of fences and under windows and drainpipes. It also says gravel drives and paths make it impossible for an intruder to approach a property quietly, that gates should be kept shut and locked, especially those to the rear, and that two locks, top and bottom, with securely fixed hinges, are a good policy.
When a security hedge becomes a neighbour problem
The government guide says Part 8 of the Anti-social Behaviour Act 2003 lets councils deal with complaints about high hedges. Councils must decide whether the hedge’s height is having an adverse effect on a neighbour’s enjoyment of their home or garden, and if so can order the owner to take action. A hedge qualifies as a “high hedge” only if it meets these tests:
- it grows on land owned or occupied by someone else;
- it is made up of a line of two or more trees or shrubs;
- it is mostly evergreen or semi-evergreen;
- it is more than 2 metres tall, measured from ground level; and
- it is a barrier to light or access, even if there are gaps.
The guide says a semi-evergreen plant is one that keeps some live or green leaves all year round, and that it does not include privet hedges that lose all their leaves in winter or beech or hornbeam hedges that keep dead leaves in winter. It says single trees or shrubs cannot be the subject of a complaint, that councils cannot deal with root problems such as subsidence, and that a council can reject a complaint if the complainant has not taken all reasonable steps to settle the dispute first. Councils can set and charge fees for handling complaints. Anyone growing a thorny evergreen boundary should therefore keep it below 2 metres if it borders a neighbour’s home, or agree the height with the neighbour first.
Insurance and the value of garden contents
The RHS says the value of equipment, structures and plants in gardens often amounts to thousands of pounds, and that most household policies offer limited cover for garden-related items, so owners should check theft cover for gardens and outbuildings. It notes that items stolen from a building are more likely to be covered than those stolen from the garden, that buildings policies cover most structures such as sheds and greenhouses but are unlikely to cover decking, pergolas or raised beds, and that there is often no cover for plants, containers and statues.
Marking, anchoring and lighting
For valuables the RHS suggests proprietary land anchors, movement detectors under items such as statuary, electronic tagging and marking property with the postcode, ideally by engraving. It advises installing outside security lighting that comes on automatically, positioned so it is not a nuisance to neighbours or a distraction for road users, and CCTV set up so that it captures only the owner’s own house and garden, because footage of a neighbour’s garden or a public area brings data protection duties.
Common questions
Is a hedge over 2 metres illegal?
No. The guide says a council can act only on a complaint about a qualifying evergreen or semi-evergreen hedge causing an adverse effect. Tall hedges are not banned in themselves.
The bottom line
The RHS treats thorny planting, sound fences, gravel, locked gates and lighting as layers of garden security, with insurance cover checked separately. In England and Wales a hedge that is evergreen or semi-evergreen and higher than 2 metres can be the subject of a council complaint, so height should be managed. Any deterrent should stay reasonable in law.