Rid your garden of unwanted insects and animals
Dealing with the pests that attack and destroy plants is all part of maintaining a healthy garden.
Here we’ll take you through how to work out which ones you’ve got and how to get rid of them – helping your garden to look good.
Tools & materials required
How to identify garden pests
Some of the most common creatures you’ll find in your garden are:
Slugs and snails
Slugs and snails love the cool, wet weather and eating tender plants such as hostas. Sweep up garden rubbish so they can’t hide under it.
Cabbage white and mullein moth caterpillars tend to cause the most problems in gardens. The former attacks nasturtiums as well as brassicas; while the latter devastates verbascums.
Controlling these caterpillars needs to be undertaken carefully so that populations of beneficial pollinating butterflies and moths are not impacted.
Aphids and whitefly
Greenfly, whitefly and blackfly are sap sucking insects that can severely disfigure flowers and growing tips. The honeydew (the sugars from inside a plant), they deposit on leaves attracts a sooty mould.
These grey long-snouted beetles don’t cause too much damage as adults – they just nibble leaf edges. But the large, fat, brown-headed, maggot-like grubs that hatch in the soil, eat every root in site.
Looking like fat brown caterpillars with no legs, they are actually the larvae of daddy longlegs. They live in the soil and feed on the roots of almost anything – they can be especially problematic in lawns, because they eat the roots of grass.
These flat, brownish sapsuckers cling to stems, like barnacles to a boat. They secrete honeydew, which encourages sooty mould to develop and bad infestations can kill plants.
Look for bumps or scales on the underside of leaves, and prune infected stems and leaves, disposing of them carefully.
Shiny black creatures that like to eat roots, millipedes are rarely a serious problem unless they occur in large numbers.
Sweep up garden rubbish regularly to help keep their numbers in check.
Red spider mites
These spiders are so tiny that they're almost invisible, but you’ll know if they’re there by the tell-tale webs between the leaves of the plants. Being sapsuckers, they cause mottling on leaves and bad infestations can kill plants.
They tend to be more of a problem in greenhouses than in the garden, but they will move out in warm dry conditions. Don't let your greenhouse get too dry as these mites thrive in drier conditions.
Look out for the mottling on leaves when choosing new plants to avoid inadvertently introducing the mites. If you do find an infestation, separate out plants that have been impacted so that they don’t infect the healthy ones.
Natural defences against pests
The best way to defend against pests is to ensure that you grow strong, healthy plants – they can withstand a bit of chomping and here and there.
Each pest also has it’s own natural predator which, if allowed to do so, is capable or controlling the problem for you – so welcome insects and other forms of wildlife into your garden that will help with you. Ladybirds, lacewings and hoverflies, for example, will devour copious quantities of aphids. Lure them with nectar-producing plants, like pansies sunflowers and flowering herbs such as santolina, lavender, sage and rosemary.
Birds can play an active role in reducing the population of caterpillars that eat our vegetables and other plants. A well-stocked bird table is one way to increase the number of birds that visit your garden. For more ideas on how to encourage birds and other wildlife into your outdoor space, check out our article on creating a bird and wildlife-friendly garden.
And remember that every garden will eventually develop its own balance.
How to control garden pests
Remove them manually
For use against slugs, snails, caterpillars and adult vine weevils
Larger pests can be picked off of your plants and disposed of. This is best done at night when they are most active – so use a torch to spot them. However, many will be too small to see easily so you may need to use other methods as well.
Create a barrier
For use against caterpillars, slugs and snails
- Lay horticultural fleece over crops susceptible to cabbage white caterpillars.
- Sprinkle sharp sand, horticultural grit or even eggshells around plants that are at risk of slug damage.
- Wrap copper-impregnated tape around pots. When slugs or snails try to cross it, a small electrical charge zaps them.
Lay a trap
For use against aphids, whitefly, wasps, slugs and snails
- Trap any aphids or whitefly in your greenhouse by using sticky yellow traps.
- To decrease the wasp population, hang wasp traps close to fruit trees before the fruit is fully ripe.
- Both beer traps (a container with some beer inside) sunk into the ground and upturned grapefruit skins attract slugs and snails. Dispose of them when full, and if a hungry hedgehog eats the slugs in the trap, they won’t be harmed.
Consider companion planting
For use against aphids
- Many insects, particularly aphids, detest strong-scented plants. Marigolds planted next to susceptible plants serve a double purpose - keeping away a variety of insect pests and attracting hoverflies, which feast on aphids.
- When growing vegetables, alternate rows of vegetables and flowers – the scent of the flowers will disguise the smell of the vegetables and will attract predators too.
Sprinkle slug pellets
For use against slugs
Many slug pellets contain metaldehyde, a toxin that can cause harm to hedgehogs and other wildlife if they eat the pellets – or slugs and snails that have been killed with the pellets. Choose pellets formulated to cause the least amount of harm to other creatures, such as our non-toxic options. Scatter them thinly and only around the plants which are the most susceptible. Always follow the instructions on the packet and dispose of dead slugs and snails that you find.
For use against most insects
Chemical pesticides can be used against most insects in your garden. However, they can increase water and soil pollution and harm your garden. So take care if using them and follow the instructions on the packaging to ensure you're using the products as safely as possible – and reducing the risk of pollution and harm to wildlife.
Those based on soft soap, insecticidal soap or quassia are non-residual and can be used against aphids, caterpillars, red spider mites, sawflies and woodlice. Though they're not selective and so will kill all insects, good and bad.
We recommend looking for organic options, as they may be less harmful to use.
For all pests
These microscopic natural predators, resembling tiny worms, are species specific – buy the right option for whichever pest you have in your garden. They’re most effective within greenhouses; less so in the open, as they need warmth to survive. They are usually sold in powder form, for mixing with water before watering onto plants and soil.
How to keep out other animals
It’s not just insects and creepy crawlies that you may need to keep out of your garden. Other animals may also be damaging to your outdoor space.
Such as cats, rats and mice
If the toilet habits of neighbourhood cats are a problem, try placing mothballs or lemon or orange peel in their favourite spots. Or spray or scatter cat-repellent in the area.
Another way to keep cats out of your garden, as well as mice, rats and other creatures, is to pick up a sonic repellent. These are designed to deter animals by emitting a noise unpleasant to their ears, but inaudible to ours.
If you have a problem with rats in your compost bin, fix a steel wire mesh across the base of the bin so that they can't access it and don't add meat or any cooked food to the compost.
Such as badgers and deer
Deer can munch through a garden overnight, with rose bushes being a favourite food. Protect your favourites with a fence at least 2.5 metres (approximately 8 foot) tall to keep them out.
Most of the time, birds are beneficial visitors to gardens, keeping many pests under control. There may be times, however, when you may want to protect crops from birds. Protect fruit bushes with netting to help you eat more of your crop.