What are deer?
Deer are mammals, usually living in woodland or scrubby areas from where they make forays into gardens. They may visit gardens as single animals but often it will be several animals that cause extensive damage very quickly.
They attack many plants, but particularly runner bean, beetroot, blackberry, raspberry, strawberry, evergreen azaleas, camellia, roses, holly, ivy, rhododendron, Viburnum tinus, hardy geraniums, Sedum spectabile, tulip and grape hyacinth. New plantings are particularly at risk. Deer are capable of eating thorny plants and also some, such as yew, which are poisonous to cattle and sheep. They also eat large amounts of fruits and berries in `the autumn. These include acorns, chestnuts, beech mast, apples and mountain ash berries. A poor crop of fruits may encourage deer to leave the woods and seek food in gardens.
Although it is permissible to control deer by shooting, this generally cannot be done in a safe and legal manner in gardens.
Netting and fencing
The most effective way of stopping deer is to exclude them from gardens with netting or fences but these need to be robust and relatively tall . Deer can squeeze through small gaps under fencing or leap over barriers that are too low.
Wire mesh fencing should be 1.5m (5ft) tall for muntjac and 1.8m (6ft) for other deer, and a heavy duty type of wire like that used to fence sheep or pigs should be used in the lower half. The bottom edge should be pegged to the ground to stop deer lifting the wire and squeezing underneath. The maximum mesh size should be 20 x 15cm (8 x 6in) for most deer but 7.5 x 7.5cm (3 x 3in) where muntjac are a problem.
Entrances to the garden need deer-proof gates. An electric fence, as used to confine farm livestock, is often ineffective against deer and may be damaged if deer are startled and try to run through it. Horizontal strands of plain or barbed wire are unlikely to be effective as roe deer can squeeze through gaps of 30cm (1ft).
Hedges can be an effective barrier if they are suitably tall and solid enough to stop deer pushing through.
A ditch on the outside will improve the effectiveness of fences or hedging.
Protecting young trees
Tree guards will be necessary to protect young trees from fraying if the garden is not fenced. The best way of doing this is to place three or four stakes or poles around the trunk so that the deer cannot get close enough to damage the bark. Additional protection can be given with wire netting. A height of 120cm (4ft) is adequate for roe deer but taller guards are needed for larger deer such as the red or fallow. The leading shoots of young trees can be protected by twisting sheep's wool around them. This will need adjustment from time to time during the growing season.
Animal deterrent sprays based on aluminium ammonium sulphate (e.g. Vitax Stay Off, Growing Success Wild Animal Repellent or Doff Wildlife Repellent Spray) may discourage deer from feeding but need frequent application in spring and summer to keep pace with new growth. Such sprays may also divert deer onto feeding on other plants that have previously been left alone.
Ultra-sonic scaring devices emit a high pitched sound that is inaudible to humans but loud to animals such as deer. These devices can be effective initially but the deterrent effect is likely to be reduced once deer have become familiar with the noise.
Another repellent that can be tried is placing human hair in bags made from muslin or old nylon tights in places where deer are feeding or entering gardens. Some people find this effective but it does not work in all gardens.
Deer keep well away from dogs, so the scent and sound of a dog kept in a kennel in the garden may be helpful.
Deer resistant plants
While deer can eat most plants, especially those that are recently planted, there are some plants that are usually left alone. It is also worthwhile seeing what plants grow successfully in other people’s gardens nearby, as that will provide some information on the feeding preferences of the local deer population.