Lemongrass smells great, and that citrusy scent does bother mosquitoes.
A living lemongrass plant does very little to keep mosquitoes off you; crushed leaves and lemongrass oil repel them briefly, and an EPA-registered repellent with DEET, picaridin, or oil of lemon eucalyptus protects you for hours longer.
So if you’re asking whether lemongrass repels mosquitoes, the honest yes comes with fine print. I’d grow it for your kitchen and your patio’s looks, and keep a proven repellent within reach when the evening biting starts.
The Short Answer: What Lemongrass Can and Can’t Do
Lemongrass works as a mosquito repellent only when its oil is released and close to your skin. A pot sitting on the patio holds that oil inside its leaves, so mosquitoes barely notice it. If you are stocking up, a lemongrass plant is the first thing I would pick up.
Here’s how the main options compare:
- Live plant: Pleasant scent up close, little to no measurable protection.
- Crushed leaves rubbed on skin: Short protection, often under an hour, plus a risk of skin irritation.
- Formulated lemongrass oil products: Real repellency in studies, but it fades in a few hours or less.
- DEET, picaridin, or oil of lemon eucalyptus: Several hours of protection, backed by EPA review.
Lemongrass earns its reputation as a natural mosquito repellent because its oil does affect mosquitoes in lab tests. The catch is strength and staying power. The oil evaporates fast, so its effect drops off quickly once you’re outdoors in heat and wind.
DEET has been studied for decades and lasts far longer per application. If you live where mosquitoes carry West Nile virus (most of the US), I’d treat lemongrass as a garden plant first and a bug fighter a distant second.
What in Lemongrass Repels Mosquitoes?
Lemongrass gets its bug-bothering power from a few strong-smelling oils packed in its leaves, mainly citral and geraniol. Those oils only work once they leave the plant and reach the air around you.
What Do Citral and Geraniol Do?
Citral is the main compound in lemongrass oil. It’s the source of that sharp lemon smell, and it often makes up well over half of the oil from West Indian lemongrass.
Geraniol is a smaller part of the mix. It’s also found in rose and geranium oils, and it shows up as an active ingredient in some natural bug sprays.
Mosquitoes find you by smelling carbon dioxide from your breath and chemicals from your skin. Researchers believe strong plant oils like citral jam or confuse those smell signals, so the mosquito has a harder time locking onto you.
That’s how lemongrass repels mosquitoes: it works through scent at close range. It doesn’t kill adult mosquitoes in normal outdoor use, and it doesn’t wall off a whole yard.
Why Does Releasing the Oil Matter?
The oil sits inside tiny cells in the leaves. A healthy plant on its own lets out only a faint trace, mostly when wind or a passing hand bends the blades.
Once you crush, cut, or distill the leaves, lemongrass oil pours out in much higher amounts. That’s why lab studies use extracts and oils, never a potted plant set beside a person.
Release also has a downside. These oils are volatile, meaning they turn into vapor and drift off fast, especially above 80°F. Whatever you release today is mostly gone within an hour or two.
Living Plants vs. Crushed Leaves vs. Essential Oil
The form you use changes everything, from almost no effect with a living plant to a few hours from a well-made product. Crushed leaves land in between, and essential oil only performs well when it’s blended into a tested formula.
Will a Living Plant Protect Your Patio?
No, I wouldn’t count on lemongrass plants to protect a patio. Researchers who test plant repellents have even had to bruise the leaves of live potted plants before they saw an effect, which tells you how little an untouched plant gives off.
Planting lemongrass is still worth it for other reasons. It’s a tall, fountain-shaped grass that looks great in a container, and you can cook with it all summer.
It also fits into companion planting ideas, though evidence that it shields nearby vegetables from pests is thin. Plant it because you like it, and set expectations low on bugs.
What Changes When You Crush the Leaves?
Crushing the leaves releases far more citral and geraniol. Rubbing a handful between your palms and then on your arms gives you a short burst of scent right where mosquitoes land.
The trade-off is time and skin. That burst fades fast, often within 30 to 60 minutes, and the sharp-edged leaves and raw oils can redden sensitive skin.
If you try it, test a small patch on your forearm first. Wash it off if it stings or itches.
How Long Might a Formulated Oil Repellent Last?
Lab-made lotions and sprays with lemongrass essential oil, often around 15% oil, have shown solid repellency in studies. Some tests found protection close to that of a commercial repellent for a couple of hours.
The base matters a lot. Thicker lotions and fixatives slow evaporation, so a well-built product lasts longer than a few drops shaken into water.
A homemade spray isn’t standardized, so you can’t know its strength. Undiluted lemongrass oil can also burn skin, so I never recommend putting it on straight.
What Do Research and Public Health Guidance Say?
Research shows lemongrass oil repels mosquitoes for a short time, while US health agencies point people toward registered repellents with proven, longer protection. Both statements are true at once.
What Have Studies Actually Tested?
Most studies test lemongrass oil or extracts, in a lab or on a few volunteers. They’ve found repellent effects against several kinds of mosquitoes, including Aedes aegypti, the yellow fever mosquito found in the Southeast and Southwest.
Some studies also show lemongrass oil kills mosquito larvae in water at high doses. That’s a lab result, and it doesn’t mean a plant near a birdbath will do the same.
What researchers haven’t shown is that growing lemongrass in a yard cuts bites. Studies of natural mosquito repellents keep reaching the same point: plant oils work, then wear off sooner than DEET does.
Why Do the CDC and EPA Recommend Registered Repellents?
The CDC recommends repellents registered with the EPA because those products have been reviewed for safety and how well they work. The approved active ingredients include DEET, picaridin, IR3535, oil of lemon eucalyptus (OLE), PMD, and 2-undecanone.
Registration means the label’s protection time is backed by data. Most lemongrass sprays you’ll find sold as “natural” are exempt from that review, so their claims aren’t checked the same way.
If you want a plant-based choice that still meets that bar, I’d pick an EPA-registered lemon eucalyptus repellent. The CDC says not to use OLE or PMD products on children under 3.
Lemongrass vs. Citronella Grass vs. the “Mosquito Plant”
Lemongrass, citronella grass, and the “mosquito plant” are three different plants, and only one of them is the main source of citronella oil. Mixing them up is the most common mix-up at garden centers.
Which Grass Produces Citronella Oil?
Citronella oil comes from citronella grass, mainly Cymbopogon nardus and Cymbopogon winterianus. Cooking lemongrass is Cymbopogon citratus, a close cousin in the same plant family.
They look alike, with long, arching blades. Citronella grass has reddish stem bases and a sharper, more perfumed smell, while lemongrass smells like lemon candy and is the one you use in soups and curries.
You can’t swap them in the kitchen. Citronella grass isn’t the culinary type, so stick with C. citratus for food. For more side-by-side detail, see my piece on citronella vs lemongrass.
Is a Citronella-Scented Geranium the Same Thing?
No. The plant sold as a “mosquito plant” or “citrosa” is a scented geranium (Pelargonium), a ferny-leaved plant whose leaves smell a bit like citronella when rubbed.
It contains only small amounts of the repelling oils. Tests on the potted plant have found little to no protection from bites.
| Lemongrass | Citronella grass | “Mosquito plant” | |
|---|---|---|---|
| Plant type | Cymbopogon citratus | C. nardus / C. winterianus | Scented geranium |
| Main scent oil | Citral | Citronellal, geraniol | Small traces |
| Edible | Yes | No | No |
| Source of citronella oil | No | Yes | No |
| Potted plant repels bites | Very little | Very little | Very little |
Will Lemongrass Repel Flies, Ants, or Ticks?
Lemongrass oil bothers some flies and ants in lab tests, but no evidence shows a plant protects you from any of them. Ticks are the biggest concern, since they spread Lyme disease across the Northeast and upper Midwest.
What Is Known About Flies and Ants?
Studies have found lemongrass oil strongly repels stable flies, the biting flies that pester livestock and people near barns. The oil has also bothered some ants, including red imported fire ants, in lab work.
Those results came from concentrated oil. A lemongrass pot by the back door won’t keep house flies off your food or stop an ant trail across the kitchen.
For ants indoors, cleaning up crumbs and sealing gaps does more. For flies on the patio, a fan and covered food work better than any herb.
Why Shouldn’t You Rely on It for Tick Protection?
Some oils related to lemongrass have repelled tick nymphs in tests, but the protection is short and untested in real outdoor use. Ticks also crawl up from grass and leaf litter, well below where any plant scent would reach.
Tick bites carry real risk. Lyme disease is common from Maine to Virginia and around the Great Lakes.
For ticks, I’d use an EPA-registered repellent on skin, treat clothing with permethrin (never on skin), and do a full tick check after time outdoors.
Can Lemongrass Get Rid of Fleas?
Lemongrass won’t get rid of fleas, and it isn’t a safe treatment to put on pets. It’s a poor fit for flea control and a real hazard for cats.
Why Isn’t It a Reliable Flea Treatment?
Lemongrass oil may bother adult fleas for a few hours, but that’s where it stops. Most of a flea problem lives as eggs, larvae, and pupae in carpet, bedding, and soil, out of reach of any spray.
The oil also evaporates fast, so you’d be spraying over and over with no lasting result. Vet-approved flea preventives last about a month per dose and target every life stage.
If you’re seeing fleas on your pet, talk with your vet. Wash pet bedding in hot water and vacuum often while the treatment works.
Is Lemongrass Safe Around Cats and Dogs?
The ASPCA lists lemon grass as toxic to cats, dogs, and horses. Chewing on the plant mainly causes stomach upset, such as vomiting and diarrhea.
Essential oils are a bigger worry than the plant. Cats lack a liver enzyme that breaks down many oil compounds, so oils on their fur or diffused in the air can cause drooling, wobbling, breathing trouble,