Asian Hornets in the Garden: When They’re Most Active and How to Keep Them Away

With the first mild days of the year comes more than the urge to get back into the garden: the Asian hornet can return too. Many people only notice when the low, heavy buzzing starts or the first stings are reported nearby. If you know when these insects are most active - and how to discourage them using straightforward measures - you can greatly reduce the chances of a nasty encounter.

Spring surprise in the garden: the hornet season begins

From April onwards, Asian hornets enter the busiest part of their year. Young queens that have made it through winter begin establishing new colonies, scouting sheltered nesting sites such as under eaves, inside sheds, in tall hedges, or high in tree canopies.

Despite what some assume, they are not harmless “big buzzy insects”. They will defend their nest forcefully. Getting too close, creating loud vibrations, or even shaking a hedge by accident can trigger a coordinated defensive response from multiple hornets.

"Asian hornets can sting repeatedly and react aggressively when they feel their nest is under threat - and their activity rises sharply, especially in spring."

Specialist bodies such as France’s National Inventory of Natural Heritage note that the main risk is not simply a single sting, but the colony’s collective defence. Compared with the European hornet, Asian hornets are more likely to attack repeatedly when they feel disturbed.

The risky time of day: when Asian hornets really step up

Hornets may be seen flying at various points throughout the day, but one window is notably more problematic in the garden: late afternoon through to dusk. At that time, foraging workers make their final trips to bring resources back to the nest.

In particular, they tend to focus on the following during this period:

• Hunting other insects, especially bees and wasps
• Seeking sugary sources such as fallen fruit, juice, lemonade, or leftovers from a barbecue
• Carrying building material to expand the nest
• Performing orientation flights around nests, often close to the ground and along hedges

As daylight fades, their flight behaviour shifts. The contrast between a darker environment and pinpoint light sources can make patio and courtyard lighting suddenly very attractive.

"At dusk, the number of hornets around lit terraces and balconies increases noticeably, and the risk of stings rises significantly during this phase."

A familiar scenario: you stay outside into the evening, the house light is on, and several large, dark insects begin hovering in front of the lamp. That is exactly when people and hornets end up dangerously close.

How to act at the critical time of day

Once you know when the danger period tends to be, it is easy to adjust your routine. A few practical habits can reduce the risk considerably:

• Schedule hedge-cutting or tidying the shed for the morning where possible
• Avoid using vibrating tools (brushcutters, hedge trimmers, leaf blowers) near any suspected nest later in the day
• Only switch on outdoor lights when genuinely needed; choose warmer, dimmer lighting if you can
• Cover open drinks, particularly sweet lemonades and juices
• Clear barbecue leftovers quickly and keep bins closed

If a hornet comes close despite precautions, the best approach is to stay calm, avoid swatting at it, and step away slowly. Sudden movements can be interpreted as a threat.

Natural methods: keeping Asian hornets at a distance

Alongside sensible behaviour, you can also shape parts of the garden so they are less appealing to hornets. Strongly scented plants can be especially helpful because they disrupt the insects’ ability to orient themselves.

Scented plants as a natural deterrent

Certain herbs and ornamental plants appear to unsettle Asian hornets. Their essential oils can mask scent trails the insects use for navigation. Many hobby gardeners report the most noticeable benefits from:

• Scented geraniums with a strong aroma
• Citronella-scented plants such as lemongrass
• Peppermint, particularly menthol-rich varieties
• Eucalyptus in pots positioned near seating areas

"Essential oils from mint, citronella and eucalyptus can interfere with hornets’ sensors - they are more likely to avoid those areas."

The advantage is that these plants usually smell pleasant to people, tend to attract bees less than typical flowering plants, and can be grown easily in pots around patios. Used this way, they create a kind of scented barrier that may redirect flight paths.

Making your garden and home a “bad address” for hornets

Beyond planting, cleanliness outdoors makes a real difference. By removing likely food sources, you make your garden less worthwhile for hornets to visit.

Key steps include:

• Don’t leave rubbish bags or food-waste bins open outdoors
• Clean barbecue areas after every use, including removing greasy residues
• Collect fallen fruit regularly, especially early apples and plums
• Check façades and roof areas for gaps and cavities and seal them
• Inspect wood sheds for old boxes and clutter where nests could be started

If you routinely tidy and seal up in March or early April, you reduce the likelihood that a queen chooses your property as the place to begin building.

What to do if a nest appears in your garden

If you spot a larger nest, the rule is simple: do not interfere. Especially during the sensitive evening period, the insects can become extremely irritable if someone approaches. DIY attempts with sprays, water, or fire are dangerous - and in many areas may also be prohibited.

Instead, take these steps:

• Keep at least 5–10 metres away and mark a clear boundary for children
• Keep pets from roaming nearby
• Briefly watch the location and the insects’ flight paths without provoking them
• Contact a pest controller or the local fire service, depending on local authority arrangements

Professionals can judge whether removal is necessary or whether the nest is in a low-risk spot where it can be left alone. Not every nest is automatically an immediate danger, but if it is close to patios, windows, or children’s play areas, experts should intervene.

How dangerous are Asian hornet stings really?

For most healthy people, a single sting is extremely painful but is rarely life-threatening. However, multiple stings, stings around the throat, or an allergic reaction can become serious.

Typical warning signs of a severe allergic response include:

• Rapid swelling extending well beyond the sting site
• Breathing difficulty or tightness in the chest or throat
• Dizziness, nausea, or circulatory problems

In these situations, call the emergency services immediately. If you already know you react allergically to other insect stings, it is best to speak to your GP before the season about an emergency kit.

Why the Asian hornet is also a problem for bees

Asian hornets mainly prey on other insects. Honeybees are particularly affected. Hornets often wait outside hives, catch returning bees in flight, and break them up to feed the protein-rich bodies to their larvae.

For beekeepers, this can lead to significant losses. In areas where Asian hornets are well established, apiaries sometimes need special mesh or protective structures so bees can still fly in and out without being constantly intercepted.

If you live near beekeepers, careful observation can help: sightings of unusually large, dark-coloured hornets near nests or directly outside hives should be reported. That makes it easier to identify hotspots quickly.

Practical tips for a more relaxed gardening summer

With a bit of planning, you do not have to give up calm evenings outside. A few extra ideas may help:

• Position your eating area slightly away from flowers or fruit trees so insects are less tempted to come straight to the table
• Use solar lights closer to the ground rather than bright spots aimed at the seating area
• Place pots of herbs such as mint or lemon balm right by balcony railings or along the patio edge
• Mark clear no-play zones for children, for example in dense, overgrown corners

Even though Asian hornets can be intimidating, knowledge and a handful of simple measures can keep them under control. By paying attention to the riskiest times of day, keeping the garden “tidy” from their point of view, and using targeted scent barriers, you can greatly lower the likelihood of dangerous close encounters - and still enjoy spring outdoors.