Many of us will know the frustration of nurturing our green spaces and watching them grow, only to step out one day and find them ravaged by garden pests.
It’s also easy to believe that pesticides are the only way to stop garden bugs from treating your flowers and vegetables as a salad bar. But, in reality, there are also plenty of natural, cost-effective ways to ward off pests and minimise harm to the environment.
From slugs and snails to lily beetles and vine weevils, here are nine common garden pests and tips on how to tackle them.
Note: While garden pest control may be helpful if you have huge populations of bugs or molluscs (slugs and snails) eating your plants, it’s also worth noting that these creatures are part of our natural ecosystem – which can usually cope with them in small numbers.
Therefore, it may be worth leaving pests alone for as long as possible to see whether your garden can control them naturally.
1. Aphids
So tiny that they can be difficult to see with the naked eye, aphids are sap-sucking insects. They weaken plants by stunting growth, distorting leaves, and producing honeydew, on which black sooty moulds can grow. Eventually, plants may die as a result.
Aphids are often referred to as ‘greenfly’ or ‘blackfly’ but there are also pink, white, yellow, and mottled species. Some species feed on specific plants – such as bean aphids, potato aphids, and woolly aphids (which attack the bark of apple trees) – while others will munch on a wide variety.
To prevent aphids and ward them off, you could try…
- Hand-squashing small infestations.
- Washing aphids off of plants with a jet hose – or spraying plants with a neem oil or soapy water spray.
- Minimising the use of nitrogen-rich fertilisers so that young plants develop tougher leaves. These are less attractive to aphids, as they prefer soft young growth.
- Growing pungent-smelling plants like garlic, onions, and sage.
- Encouraging predators like ladybirds, hoverflies, and birds – the RHS has tips on how to do this here.
Fun fact: Adult aphids are often wingless but may develop wings when populations get crowded to help them go in search of other food sources.
2. Slugs or snails
Slugs are active all year, while snails will become dormant during autumn and winter. However, both can become particularly problematic for your garden in the spring and summer, when there are plenty of tasty young shoots for them to feed on.
While slugs aren’t too fussy and will eat a wide variety of plants, delphiniums, dahlias, gerberas, sweet peas, hostas, and tulips are among those regularly attacked.
Slugs and snails are most active at night and love warm, damp conditions, so they’ll often come out after it’s rained. In cold conditions or when it’s hot and dry, slugs and snails bury themselves in the soil to preserve body heat and moisture.
To protect your garden plants from slugs and snails, you could try…
- Lining the edges and borders of your pots and beds with upturned eggshells – the sharp edges will stop them from sliding past.
- Mulching the perimeter of your garden beds with seaweed, which is a natural slug and snail repellent.
- Installing a pond to attract predators like toads and newts.
- Planting greenery that naturally repels them, like chives, garlic, fennel, foxgloves, and geraniums.
- Placing a rough layer of sand or gravel around your plants to make sliding towards them more difficult.
Fun fact: Slugs can stretch to 20 times their length to allow them to squeeze into the smallest of spaces in search of food.
3. Adult vine weevil
Adult vine weevils are small, beetle-like creatures that measure around 10mm in length, and are usually dark brown or black in colour. One of their distinctive features is their lack of wings, which sets them apart from many other beetles.
These persistent pests mostly emerge during the night and are known for their nocturnal activities. They feed on various plants but particularly enjoy strawberries, cyclamen, fuchsia, primulas, polyanthus, and heucheras – causing unsightly notches and damage on leaves.
Adult vine weevils can also reproduce quickly, laying eggs that eventually hatch into destructive, root-eating grubs.
To stop adult vine weevils from destroying your plants, you could try…
- Laying sticky traps down around pots – they walk from one place to another so this method often works well.
- Picking them off by hand. The best time to do this is at night by torchlight, as this is when adult vine weevils tend to feed.
- Choosing garden plants like hebes or heucheras, which are natural repellents.
- Placing an upturned umbrella, newspaper, or tray underneath an infected plant and shaking it to dislodge them.
- Attracting natural predators to your garden, like birds, frogs, shrews, and hedgehogs – you can find out more about creating a wildlife-friendly garden in our article here.
Fun fact: Adult vine weevils are surprisingly good at playing hide-and-seek! These crafty insects have a unique ability to tuck in their legs and drop to the ground when disturbed or approached.
So, if you ever find yourself in a game of hide-and-seek with adult vine weevils, don’t be surprised if they effortlessly outwit you with their disappearing act!
4. Vine weevil grub
These white, C-shaped grubs have a brown head and a soft, squishy body – and are the larvae of adult vine weevils. In contrast to their elders, they mainly feed on the roots of plants, causing significant damage.
These voracious eaters grow up to 10mm long and can chew through plant roots, leading to wilting, stunted growth, and eventually even death.
Vine weevil grubs are particularly notorious for infesting potted plants and containers. And, gardeners often struggle to combat them due to their ability to hide in soil and resilience to many control methods.
If you’re concerned about the impact of vine weevil grubs on your plants, you could try…
- Removing as many as possible from the compost.
- Introducing beneficial nematodes to the soil – which are available online from Nematodes Direct. These microscopic worms act as parasites and can reduce weevil grub populations naturally.
- Sprinkling diatomaceous earth around the base of affected plants. Diatomaceous earth is made from fossilised remains of algae-like organisms and when insects crawl across it, they become dehydrated and die.
- Making sure the soil is well-drained and not excessively moist, as vine beetle grubs thrive in damp conditions. Try to water only when necessary.
Fun fact: Vine weevil grubs have a unique defence mechanism called ‘harping’. When threatened, they’ll arch their body, striking a pose similar to a scorpion to make themselves appear larger and more intimidating.
5. Lily beetle
Lily beetles are colourful, destructive insects that pose a threat to lilies and other plants in the genus Lilium. These beetles are 8-10mm in length, have vibrant red bodies with black heads and legs, and are easily recognisable due to their distinct appearance.
There are 250 lily beetle species in the UK and they all feed on the foliage, flowers, and buds of lilies and fritillaries – chewing through leaves, and leaving behind holes and skeletonised foliage.
Female lily beetles lay eggs on the undersides of leaves, and these later hatch into brownish grubs that also feed on the plants.
To help control lily beetle populations in your garden, you could try…
- Removing them from plants by hand – though you’ll need to be quick, as they fall to the ground and lie on their backs (where they blend in with the soil or concrete) at the first sign of danger! Spreading newspaper on the ground first can help to catch falling lily beetles.
- Spraying neem oil or garlic and onion spray on your lilies – as these act as natural insecticides.
- Encouraging wildlife such as frogs, birds, wasps, and predatory ground beetles who’ll eat them, and sometimes adults too.
- Planting marigolds, chives, ‘Defender Pink’ lilies, or geraniums, to naturally deter them.
Fun fact: As lily beetles munch their way through leaves, they leave piles of droppings, known as ‘frass’, which they then cover themselves in to hide from predators.
6. Glasshouse thrips
There are 150 different species of glasshouse thrips in the UK – some of which can cause mottling to plants and spread plant viruses.
These small pests have long, narrow bodies; wings fringed with short hairs; and can be yellow, brown, or black in colour. They love to feed on plants by sucking out their juices, leaving behind silver or bronze streaks on leaves.
Glasshouse thrips multiply quickly and can eat a wide variety of greenhouse plants. However, some of their favourite snacks include African violets, streptocarpus, fuschia, achimenes verbena, tomatoes, and cucumber.
If you can tolerate extensive silvery mottling on your plants, you may be reassured to know that many will survive thrips damage. But, if these critters are causing you concern, you could try…
- Hanging blue sticky traps in your greenhouse. It’s best to avoid using these outside so as not to harm other wildlife.
- Placing a reflective surface (such as CDs or tinfoil) over the top of your soil to disorient them.
- Using a strong jet of water to blast them off.
- Pruning back invested plants.
- Encouraging beneficial enemies like ladybirds, lacewings, and a species of pirate bug called orius laevigatus – which can be bought at some garden centres (mostly online).
Fun fact: Glasshouse thrips possess a peculiar method of getting around called ‘thrips tripping’. Instead of flying or walking like most insects, glasshouse thrips perform a unique combination of jumping and somersaulting to help them navigate through plants and evade predators.
7. Earwig
Earwigs can be up to half an inch long and have slender bodies with pincers at the back. Although they can look a bit scary, they’re mostly harmless to humans.
Found in gardens and homes, earwigs feed on a variety of things like insects, plants – particularly dahlia, clematis, and chrysanthemums – and decaying matter.
These nocturnal bugs prefer dark, damp places, so you might find them hiding in crevices or under pots. The RHS recommends trying to tolerate earwigs as much as possible, as they’re part of the natural balance and can help to reduce aphid numbers.
However, if their numbers become excessive, you could regain some control of your green space by…
- Spreading petroleum jelly around plant stems, to put earwigs off crawling over them.
- Shaking the branches of an infected plant over a coloured cloth to catch and relocate them.
- Creating simple traps using upturned plant pots, or rolled-up newspapers/cardboard tubes, with one end taped shut. Earwigs will seek shelter in these traps allowing you to collect and empty them out somewhere else each morning.
- Using strong scents to repel them – such as crushed garlic or chilli pepper mixed with water – and spray them on or around plants.
Fun fact: Earwigs have wings but don’t tend to fly, and will usually only do so if they’re frustrated by a lack of food or suitable mates.
8. Scale insects
Adult scale insects and young scale ‘nymphs’ feed on plant sap, which can weaken or kill plants over time.
Newly hatched nymphs crawl across plant stems and leaves looking for somewhere to feed and spend the rest of their lives. However, mature males and females are quite different.
When females mature, they lose their legs, becoming fixed to one spot on leaves or stems, and secreting a white, waxy coating (which looks like fish scales) for protection. Like some of the other pests in this article, female scale insects will often secrete honeydew, which can also affect plant health.
Males, on the other hand, never feed, keep their legs, and may have wings – which they use to help them find a mate. But they only have a couple of days to do so before they die.
If scale nymphs are wreaking havoc on your garden, you might want to try…
- Pruning heavily infected plants.
- Gently scraping off scale nymphs using a soft brush, cloth, or your fingernail.
- Attracting blue tits to your garden to eat them! Try installing a bird nesting box or putting sunflower seeds and chopped peanuts in your bird feeder.
- Spraying plants thoroughly every 4-7 days with a solution of mild washing-up liquid and tepid water – or you could use neem oil.
Fun fact: Female scale insects can lay as many as 20 to 400 eggs at one time.
9. Glasshouse whitefly
Resembling tiny moths, glasshouse whiteflies are small, winged insects that gather in groups on the underside of plant leaves to feed and lay eggs.
They’re closely related to aphids but are a bit smaller at around 1-2mm long and mostly affect greenhouse plants, such as tomatoes, cucumbers, and fuchsias.
Like aphids, glasshouse whiteflies suck sap from plants, causing leaves to shrivel, turn yellow, or drop prematurely – and also produce sticky honeydew, which can encourage sooty moulds to grow.
To stop glasshouse whitefly from overrunning your plants, you could try…
- Hanging yellow sticky traps in your greenhouse to catch them.
- Introducing the parasitic wasp, encarsia formosa, to attack young whiteflies and control numbers naturally. You can buy this online – for example on the Crocus website.
- Drenching plants with a soap-based spray every couple of days to keep fly numbers down as adults start to emerge.
- Growing strong-smelling plants – such as basil, lavender, and French marigolds.
Fun fact: Whiteflies can travel hundreds or even thousands of miles with the support of wind currents – sometimes crossing vast bodies of water in the process. So, next time you see a whitefly, remember that it may have travelled a long way before making an appearance in your garden!
Final thoughts…
After putting a lot of time and effort into caring for your garden, it can be disheartening to see it being eaten alive by various critters.
But, it’s important to remember that tolerating some damage can give your green space an overall greater advantage – by helping it to become a self-sustaining, self-regulated ecosystem.
However, if your garden is getting overrun by certain pests and looking a little worse for wear, or you want to try and avoid pest problems altogether, hopefully, you’ll find some of our tips useful.
For more ideas on how you can make your garden look its best, check out the gardening section of our website. Here, you’ll find everything from monthly garden checklists to lists of plants that look good all year round.
Are you having trouble with garden pests? Do you have any of your own natural control methods that you’d like to share? We’d love to hear from you in the comments below.