The European hornet is the only true hornet established in Maryland, and if you’ve spotted a large, loud, reddish-brown and yellow wasp around your property, this is almost certainly what you’re looking at. Workers measure up to an inch long, and queens can reach 1.3 inches, making them among the largest wasps in the eastern United States. They’ve been present in the region since the 1800s, and while they look alarming, they’re a known part of the local ecosystem, not the invasive northern giant hornet that made national headlines.
How to Identify a European Hornet
European hornets have a distinctive color pattern that sets them apart from yellowjackets and other wasps. The head is red-brown and yellow, the middle section (thorax) is black and reddish-brown, and the abdomen is black toward the front and yellow toward the rear with rows of black teardrop-shaped markings. That teardrop pattern on the abdomen is the single best field mark. Yellowjackets, by contrast, have crisp black-and-yellow bands and are noticeably smaller, roughly half an inch long.
The size alone is usually enough to narrow things down. If the wasp buzzing around your porch light is close to an inch long and has warm brown tones rather than pure black and yellow, you’re looking at a European hornet.
European Hornet vs. Northern Giant Hornet
Many Maryland residents who spot a European hornet for the first time worry it might be a northern giant hornet (sometimes still called the “murder hornet”). The two are easy to tell apart. Northern giant hornets are significantly larger, ranging from one to nearly two inches long, roughly double the bulk of a European hornet. Their abdominal markings are uniform yellow-orange bands rather than the European hornet’s irregular teardrop pattern. Most importantly, northern giant hornets have never been found east of the Pacific Northwest, and they do not occur east of the Rocky Mountains. If you’re in Maryland, you can confidently rule them out.
Nocturnal Habits and Light Attraction
One behavior that catches people off guard is that European hornets are active at night. Unlike most wasps, workers do much of their foraging after dark. This means you may hear them thumping against windows or swarming porch lights on summer evenings. If a large wasp flies into your home through an open door at night, it’s almost certainly a European hornet drawn by indoor lighting. Turning off exterior lights or switching to yellow “bug” bulbs can reduce these encounters.
Bark Stripping and Tree Damage
European hornets cause a type of plant damage that puzzles many homeowners. During late summer and early fall, you may notice sections of bark stripped from branches of birch, rhododendron, and lilac. The hornets use their powerful mandibles to gouge away bark for two reasons: they mix the woody fiber with saliva to build their paper nests, and they feed on the sap that flows from the wound. Young larvae in the colony also get nourishment from these bark fibers.
The damage pattern sometimes looks as though something ate corn on the cob, spiraling around a branch. If the bark removal encircles the entire branch, that branch will die because its internal transport tissues are severed. Making matters worse, hornets tend to return to the same tree or shrub season after season, compounding the injury over time. If you’re noticing mysterious branch dieback on ornamental shrubs, European hornets are a likely culprit.
Sting Risk and Reactions
European hornets can sting, and they will defend their nest aggressively if it’s disturbed. Away from the nest, though, they’re less confrontational than yellowjackets. Yellowjackets are the most common stinging culprit in Maryland, especially in late summer when colonies peak and workers scavenge around trash cans and outdoor meals. European hornets are more focused on hunting insects and stripping bark.
A single sting from a European hornet produces pain, redness, and swelling similar to other wasp stings. For most people, these symptoms resolve on their own. A non-life-threatening allergic reaction can include hives, swelling away from the sting site, headache, and stomach upset. Severe allergic reactions (anaphylaxis) are rarer but serious, with symptoms like difficulty breathing, a weak and rapid pulse, swelling of the face or throat, and dizziness or loss of consciousness. Anaphylaxis typically develops within minutes of a sting and requires emergency treatment.
Multiple stings carry their own risk even without an allergy. More than a dozen stings can cause a toxic venom reaction with nausea, vomiting, diarrhea, headache, dizziness, and fever. Children, older adults, and people with heart or respiratory conditions are especially vulnerable.
Nest Locations Around Maryland Homes
European hornets prefer to build nests in sheltered cavities. Hollow trees are a natural choice, but around homes they commonly nest inside wall voids, attics, barns, and sheds. The nest itself is made of the same chewed-wood paper material as other wasp nests, grayish-brown and roughly football-shaped when fully developed. Colonies are annual: a single fertilized queen starts the nest in spring, the colony grows through summer, and the entire population dies off after the first hard frost in fall. Only newly mated queens survive the winter, hibernating in protected spots to start the cycle again the following year.
Managing a Nest on Your Property
If a European hornet nest is in a location you can simply avoid, the easiest approach is to wait it out. The colony will die naturally with the first killing frost in late autumn, and the nest won’t be reused the following year. This is the approach University of Maryland Extension recommends as a first option.
When the nest is in a high-traffic area or inside a structure, removal may be necessary. A dust-based or aerosol wasp spray applied directly at the nest entrance can work, but the full effect takes several days as returning foragers contact the residue. Treat at night when most workers are inside the nest. Do not attempt home remedies like flooding the nest with water or setting it on fire. These methods rarely work and are likely to provoke a mass defensive response from agitated hornets.
For nests that are hard to reach, inside wall voids, or near areas where children play, hiring a pest control professional is the safer choice. A poorly executed treatment can scatter workers and increase sting risk for days afterward.
Do You Need to Report Them?
European hornets are not an invasive species requiring reporting in Maryland. They’ve been established in the eastern U.S. for well over a century and are considered a naturalized part of the insect community. Maryland’s agriculture department does not treat them as a pest of regulatory concern. You don’t need to contact any state agency if you find one. If you’re uncertain whether the hornet you’ve found is a European hornet or something unfamiliar, your local University of Maryland Extension office can help with identification.