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Pest Control

What Smells Do Mosquitoes Hate? What Works and What Does Not

Citronella, lavender and peppermint all repel mosquitoes in a lab. Almost none of it survives contact with a real backyard — here is what actually reduces bites.

By The Grow In Backyard Team 4 min read Save to Pinterest — opens Pinterest in a new tab
An Aedes mosquito feeding on human skin
Photo: NIAID, CC BY 2.0, via Wikimedia Commons
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Nearly every plant-based mosquito repellent has a study behind it showing that it works. The studies are usually real. The problem is what they measure: a compound, at concentration, on skin, in still air, for twenty minutes — which is very little like a backyard in July.

Here is the honest version of what smells mosquitoes avoid, and what that is worth to you.

The smells, ranked honestly

What the evidence supports
SmellRepels in a lab?Useful in a yard?Notes
Oil of lemon eucalyptus (PMD)Yes, stronglyYesCDC-recognised; hours of protection on skin
Citronella oilYesWeaklyEvaporates fast; a candle covers a small still-air zone
Clove, thyme, cinnamon oilsYes, stronglyBrieflyEffective but short-lived; can irritate skin neat
Peppermint, eucalyptusYesBrieflyUnder an hour, typically much less
LavenderMildlyNoPleasant; not a repellent in practice
MarigoldMildlyNoThe reputation is mostly about soil nematodes, not mosquitoes
Garlic (eaten)NoNoRepeatedly tested, repeatedly fails
VanillaMildlyNoSometimes used to extend other repellents
Mouthwash, dryer sheetsTraceNoViral, not real
Smoke, any kindYesSomewhatGenuinely disrupts host-finding — a plain fire works too

Never apply undiluted essential oils to skin

Clove, cinnamon, and thyme oils are effective partly because they are aggressive, and neat they cause chemical burns and sensitisation. Dilute to a few percent in a carrier oil, and patch test. Oil of lemon eucalyptus is also not recommended for children under three.

Why growing the plants does nothing

This is the single most repeated piece of garden advice that simply does not hold up.

The repellent compounds in citronella grass, lavender, or lemon balm are stored inside the leaf, in oil glands. An undisturbed plant releases a trace amount into the air — orders of magnitude below what a mosquito would notice from a few feet away. In trials where people crush the leaves and rub them on skin, there is a real effect; it lasts under an hour.

Plant them because they are nice plants. Do not plant them expecting fewer bites.

What actually reduces bites

1. Remove standing water. This is the whole game. Mosquitoes breed in a bottle cap’s worth of water, and most of the ones biting you hatched within a few hundred feet. Once a week, tip out saucers, gutters, tarps, toys, wheelbarrows, and buckets. For water you cannot drain — ponds, rain barrels, water features — Bti dunks (Bacillus thuringiensis israelensis) kill larvae and are harmless to fish, pets, birds, and people.

2. Run a fan. Mosquitoes are feeble fliers and cannot make progress into moving air; a box fan on a patio is more effective than every candle on the table. It also disperses the CO₂ plume that leads them to you in the first place.

3. Use a real repellent on skin. EPA-registered actives:

  • Picaridin 20% — as effective as DEET, no odour, does not melt plastics. The best default.
  • DEET 20–30% — the benchmark; higher percentages last longer rather than working better.
  • Oil of lemon eucalyptus / PMD — the effective botanical option.
  • IR3535 — milder, shorter-lasting.

4. Treat clothing with permethrin, not skin. It survives several washes and is very effective.

5. Cover up at dawn and dusk, when most biting species are active.

What to skip

Bug zappers. Studies of catch composition consistently find mosquitoes make up a tiny fraction of the kill, while large numbers of harmless and beneficial insects — including moths and pollinators — die in them. They are a net negative for a garden.

Ultrasonic repellers. Tested repeatedly. They do not work.

Backyard fogging services, unless you have a genuine reason. Broad-spectrum pyrethroid application kills pollinators and the predatory insects that were eating pests for you, and the mosquitoes fly back in from next door within days.

Bti is the underrated one

If you have a pond, a rain barrel, or a low spot that holds water, Bti dunks quietly do more than anything you can spray or burn. They break the breeding cycle rather than fighting the adults.

Common questions

What smell do mosquitoes hate the most?

Of the plant-derived smells, oil of lemon eucalyptus is the clear leader — its active compound PMD is the only botanical the CDC lists alongside synthetic repellents, and it gives several hours of protection when applied to skin at proper concentration. Citronella, lavender, peppermint, and clove all repel mosquitoes in laboratory tests but wear off within minutes to an hour, which is why they underperform so badly in a real yard.

Do citronella candles actually work?

Barely, and only in the immediate zone around the candle in still air. Studies generally find single-figure to modest percentage reductions in bites, and any breeze disperses the plume entirely. Much of what a candle does is produce smoke, which interferes with mosquitoes finding you — a plain smoky fire performs about as well as a citronella one.

Do mosquito-repelling plants work if you just grow them?

No. A living plant releases very little of its aromatic oil into the air — the compounds are locked in the leaf until something crushes it. You would need to crush handfuls of leaves and rub them on skin to get an effect, and even then it lasts under an hour. Growing citronella grass, lavender, or marigolds around a patio is pleasant, but it does not measurably reduce bites.

What is the most effective mosquito repellent?

For skin, the EPA-registered actives: DEET, picaridin, oil of lemon eucalyptus (PMD), and IR3535. Picaridin at 20% performs comparably to DEET without the plastic-dissolving and odour drawbacks. For an area rather than a person, a running fan is genuinely effective — mosquitoes are weak fliers and cannot make headway in moving air.

Does vanilla or listerine keep mosquitoes away?

Not meaningfully. Vanillin does have mild repellent properties and is sometimes used to extend other repellents, but on its own it is weak and brief. Mouthwash owes any effect to its small eucalyptol content, at concentrations far below what would matter, and it evaporates within minutes — the viral videos showing it clearing a yard do not survive controlled testing.

What attracts mosquitoes to some people more than others?

Carbon dioxide from your breath at distance, then body heat and skin chemistry up close — particularly lactic acid, ammonia, and the specific mix of bacteria on your skin. Blood type, pregnancy, exercise, and beer consumption all show measurable effects in studies. You cannot change most of that, which is why removing breeding sites and using a real repellent beats trying to smell different.

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