What really keeps mosquitoes away? Probably not your lavender plants.

While everyone knows that slathering yourself with a spray that contains DEET can effectively keep mosquitoes at bay, plenty of articles and lists online also offer other solutions — including surrounding yourself with scented plants. Studies do show that citronella, geranium, peppermint and other fragrant plants can indeed help deter mosquitoes, but the bottom line is that just having those scents around probably won’t stop the pesky insects from biting you. Here’s why.

How scents affect mosquitoes

“Mosquitoes have several olfactory cues to attract them to a host,” says Dan Markowski, technical adviser at the American Mosquito Control Association. “The primary one is carbon dioxide, and that’s considered a long-range attractant. They can pick that up over many hundreds of feet.” Then, as they approach you, he says, they detect body heat and use odors from the skin to determine whether they’d like to bite you or someone else. So when nearby plants emit a scent that masks that human odor and/or confuses a mosquito’s olfactory senses, the insect often moves away.

Citronella has been reported to have some ability to do this, Markowski says. Lemon eucalyptus, certain geraniums, lemongrass, mint and even catnip can deter mosquitoes to varying degrees, he adds.

Marigolds, on the other hand, while widely used in vegetable gardens, don’t necessarily repel mosquitoes. Instead, their distinct scent attracts beneficial insects that eat aphids and other pests but not mosquitoes. Scents of herbs and aromatics — including lavender, rosemary, thyme, basil and garlic — also can repel mosquitoes, especially when used in diffusers. But the effectiveness of these plants varies widely, in part depending on where you plant them.

“If you’ve got [plants] in the back of your yard and your deck or patio’s 20 feet away …” Markowski says, the mosquitoes “may stay out of your garden, but they’ll come find you on your patio.” Placing potted plants close to your body can repel them to a mild degree, but a determined mosquito will fly around the plant and land on you.

Plant oil extraction

There’s good reason for that determination, says Chelsea McKinley, plant-health-care specialist at the U.S. Botanic Garden. “They’re hungry. They want food.” To prevent bites, she says, you’d have to apply a plant’s scent directly to your skin. But just rubbing lemongrass or mint leaves on your arms isn’t effective. The scent, which exists in the plant’s oils, needs to be extracted.

While you might find anecdotal advice online on how to grind or boil the leaves, making home remedies isn’t safe, largely because of allergy and potency issues. An alternative is to buy natural repellent products made with essential oils, a growing market that includes sprays and creams made from the oils of mint, citronella, lavender and other plants. Brands such as Murphy’s Naturals or All Terrain can be found online or in organic food stores.

Still, choosing a repellent can be overwhelming. “The one that has the most research and the highest efficacy in terms of working,” McKinley says, “is lemon eucalyptus.” For it to be effective, she says, make sure to cover your skin thoroughly; anywhere there isn’t oil, mosquitoes are likely to land and bite you. Keep in mind, though, that the scent is often quite pungent, and it can evaporate from the skin in a few hours.

Mosquito type

Another complicating factor is that not all scents, even in their natural oil form, will be 100% effective against all types of mosquitoes. “In any given municipality in the United States, there’s 30 to 40 different species,” Markowski says. “Some are far more aggressive than others.”

For instance, salt-marsh mosquitoes in coastal areas can breed in the billions per acre and fly long distances. They will follow you around with the aim of biting, sometimes multiple times, even during daylight hours.

To learn more about your local mosquito population, try contacting your mosquito abatement district. These local organizations offer information on which mosquito species inhabit your area, how abundant they are and what can be done to reduce their numbers. In some cases, district workers will even come to your property and assess it for you. A simple online search on your county and the words “mosquito control” will bring up your local office.

Mosquito reduction strategies

In the end, the best way to reduce mosquitoes is by preventing them from breeding nearby. Remove standing water everywhere on your property, including in gutters, toys, patio furniture and pot saucers. Apply BTI (Bacillus thuringiensis israelensis), a mosquito larvae-killing product, to still ponds or birdbaths. “Anywhere there’s a teaspoon of water standing for 24 hours,” McKinley says, “you’re going to get mosquitoes breeding.”

Another strategy is to attract the wildlife that eat mosquitoes, including bats and birds, McKinley says. “Creating a habitat that’s conducive to that wildlife can help,” she says, “but you probably won’t see a dramatic reduction.” That’s because mosquitoes in a neighborhood, especially invasive species, often drastically outnumber the birds and bats visiting one person’s backyard. Mosquito traps with fans and funnels have shown good efficacy, especially when multiple neighbors on adjacent properties use them.

Also remember that sun can be deadly to mosquitoes. Markowski recommends reducing shady, humid areas where the insects hide from the heat, including ornamental grasses, dense shrubs, carports and rocks near ponds.

And the best way to keep a mosquito from biting you? “Get a fan,” McKinley says, “a big fan, and have the fan blowing directly on you.” Make sure the wind is blowing on all areas of your body, including the legs. “Mosquitoes can’t land on you if there’s wind,” she adds.