Does Citronella Work? What You Should Know About Citronella Plants
- Give A Shit About Nature
- April 12, 2026
- Sustainable Living
- 0 Comments
If you’ve ever bought a citronella candle, planted a “mosquito plant” on your patio, or spritzed on a citronella-based bug spray before a backyard cookout, you’ve participated in one of the most enduring experiments in natural pest control. Citronella is everywhere in the insect repellent space — candles, sprays, bracelets, torches, plants. But does it actually work?
The honest answer is: it depends entirely on the form. Citronella oil applied to skin is a legitimate repellent. A citronella candle on your patio table is closer to ambiance than armor. And the popular “citronella plant” sold at garden centers every spring? It smells wonderful and does almost nothing just sitting there.
Here’s everything worth knowing.
What is citronella?
Citronella is a naturally occurring essential oil derived primarily from two grasses in the Cymbopogon genus — Cymbopogon nardus and Cymbopogon winterianus, both native to tropical Asia. The oil contains compounds — primarily citronellal, geraniol, and citronellol — that mosquitoes and other insects find repellent.
Citronella oil has been used as an insect repellent for over a century and is registered with the EPA as a biopesticide. It’s one of the few plant-derived repellents with a long enough track record to have accumulated meaningful research.
What is a citronella plant?
Here’s where things get confusing. When garden centers sell a “citronella plant,” they’re almost always selling Pelargonium citrosum — a scented geranium, not the grass that actually produces commercial citronella oil. It smells strongly of citronella when you rub its leaves, which is why the marketing works, but it is not the same plant and does not produce the same oils in the same concentrations.
The actual citronella grass (Cymbopogon nardus or Cymbopogon winterianus) is the source of commercial citronella oil. It grows as a large clumping grass, looks nothing like the geranium sold at your local nursery, and is less commonly available in the ornamental plant trade.
Both plants have their merits. But it’s worth knowing which one you have.
Does citronella repel mosquitoes?
Yes — when the oil is properly applied to skin or clothing. Citronella oil is a legitimate, EPA-registered insect repellent. The CDC lists it as an option for mosquito repellency, though it notes that protection duration is shorter than DEET, picaridin, or oil of lemon eucalyptus.
Studies generally show that skin-applied citronella formulations provide meaningful repellency for approximately 30 minutes to two hours, depending on concentration, formulation, and conditions. Higher-concentration products and formulations that incorporate fixatives to slow evaporation perform better. Reapplication is necessary more frequently than with synthetic repellents.
The citronella plant, however, does not passively repel mosquitoes. A plant sitting on your deck releases very little of its volatile oils into the surrounding air — not nearly enough to create a repellent effect. You would need to crush the leaves and apply the oil to your skin to get any repellent benefit, at which point you’re using the plant as a very low-yield oil source, not a garden deterrent.
Does the citronella plant repel mosquitoes just by being nearby?
No, not meaningfully. This is the most important thing to understand about citronella plants and one of the most persistent myths in the natural pest control space.
A 2011 study published in HortScience tested several common “mosquito-repelling” plants, including Pelargonium citrosum, under real conditions. The researchers found no significant reduction in mosquito landings near the intact plants compared to controls. The compounds need to be volatilized — released into the air — in much higher concentrations than an undisturbed plant produces.
This doesn’t mean the plant is useless. It’s a beautiful, fragrant garden plant that can provide small amounts of crushed-leaf oil when you need it. But marketing it as a passive mosquito barrier is not supported by science.
Do citronella candles work?
Somewhat, and only under specific conditions. Citronella candles do release citronella oil as they burn, and in very close proximity — within a foot or two of the flame — there is a measurable repellent effect. Beyond that range, the concentration drops quickly.
A 2017 study in the Journal of Insect Science compared DEET, a spatial repellent (metofluthrin), and citronella candles for outdoor mosquito protection. Citronella candles reduced mosquito landings by about 42% compared to no treatment, while DEET reduced them by 83%. More importantly, the candle’s effect was highly localized and degraded rapidly in any wind.
The practical takeaway: citronella candles provide modest protection in a very small, still-air zone. In any breeze — which is most of the time outdoors — their effectiveness drops significantly. They’re not useless, but they shouldn’t be your primary or only defense.
Does citronella repel flies?
Yes, to a degree. Citronella oil has demonstrated repellent effects against several fly species, including house flies and stable flies. The same caveats apply: applied citronella oil is more effective than passive plant or candle sources. As a component of a fly repellent spray, citronella can contribute meaningfully. As a candle or untouched plant, the effect will be limited.
Does citronella repel gnats?
There is some evidence that citronella repels fungus gnats and some other small fly species, but research specifically on gnats is thinner than on mosquitoes. Topical application will be more effective than passive sources. If gnats are your primary concern, addressing moisture and organic matter — their breeding conditions — will do more than any repellent.
Does citronella repel bees and wasps?
This is a common question, and the answer is nuanced. Some studies suggest that certain components of citronella, particularly citronellal, can deter bees at high concentrations. However, the effects are inconsistent, and bees are not reliably repelled by citronella products at the concentrations typically found in candles or sprays.
Wasps show some sensitivity to citronella as well, but again, results vary. If stinging insects are your concern, citronella is unlikely to be a reliable solution. Identifying and removing nest sites, keeping food covered, and avoiding sweet scents and bright floral patterns are more effective strategies.
Importantly: try not to harm bees in your pest control efforts. Bees are essential pollinators facing serious population pressures. Repellents are far preferable to insecticides in any area where bees are present.
Is citronella safe for dogs?
This is where pet owners need to pay attention. Citronella is toxic to dogs. It can cause skin irritation on contact, and ingestion — eating the plant, licking citronella oil off skin, or chewing on candles — can cause vomiting, lethargy, and in significant amounts, more serious symptoms.
If you use citronella products outdoors, keep dogs away from treated surfaces and out of reach of candles. The Pelargonium citrosum plant (the garden citronella) is also considered toxic to dogs by the ASPCA. If you suspect your dog has ingested citronella oil or plant material, contact your veterinarian or the ASPCA Animal Poison Control Center at (888) 426-4435.
Is citronella safe for cats?
Cats are even more sensitive to citronella than dogs. Felines lack certain liver enzymes needed to metabolize many essential oils, including those found in citronella, making them more vulnerable to toxicity. Symptoms of citronella exposure in cats include drooling, weakness, and vomiting.
Keep citronella candles, sprays, and plants away from cats. The ASPCA lists Pelargonium species as toxic to cats. If you’re using citronella products in a home with cats, ensure they can’t access treated areas or products directly.
Is citronella a perennial?
It depends on where you live. The garden citronella (Pelargonium citrosum) is a tender perennial — it’s perennial in USDA hardiness zones 9 through 11, where winters are mild. In zones 8 and below, it’s typically grown as an annual or brought indoors before the first frost.
True citronella grass (Cymbopogon nardus) is also a tropical perennial, hardy in zones 10 to 12 in the ground, and grown as an annual or container plant elsewhere.
If you’re in a colder climate and want to overwinter your citronella plant, bring it inside before temperatures drop below 40°F. It does well in a sunny window and can be moved back outdoors in spring after the last frost date.
How to care for a citronella plant
Citronella plants are not demanding, but they do have preferences.
Light: Full sun to partial shade. At least six hours of direct sun produces the most robust growth and strongest fragrance.
Water: Moderate and consistent. Let the top inch of soil dry out between waterings. Overwatering is the most common mistake — citronella plants are susceptible to root rot in waterlogged soil.
Soil: Well-draining is essential. A standard potting mix with added perlite works well in containers. In-ground plants benefit from raised beds or slopes that prevent water from pooling.
Fertilizer: A balanced liquid fertilizer every two to four weeks during the growing season supports healthy growth. Reduce or stop feeding in winter if the plant is kept indoors.
Pruning: Pinch back stem tips regularly to encourage bushy growth and prevent legginess. Remove dead or yellowing leaves as they appear.
Container growing: Citronella plants thrive in containers, which has the added benefit of letting you move them indoors for winter. Choose a pot with good drainage and repot every one to two years as the plant grows.
How to grow citronella from seed or cuttings
From seed: Citronella seeds can be started indoors six to eight weeks before the last frost. Sow seeds on the surface of moist seed-starting mix — they need light to germinate — and keep warm (70–75°F) until sprouts appear in ten to twenty days. Transplant outdoors after frost danger has passed.
From cuttings: This is the easier and more reliable method. Take a stem cutting of four to six inches from a healthy plant, remove the lower leaves, and place in a glass of water or directly into moist potting mix. Roots typically develop within two to three weeks. Cuttings taken in late summer can be rooted and kept indoors over winter as a free way to carry your plant through to the following spring.
Where to buy citronella plants
Citronella plants are widely available at garden centers, home improvement stores, and nurseries in spring and early summer — typically from April through June. Look for them in the herb or annual sections; they’re often sold alongside rosemary, lavender, and other fragrant plants.
Online, they’re available through Amazon, Etsy (for small sellers and unusual varieties), and nursery-specific retailers like Logee’s and Burpee. If you’re looking for true citronella grass rather than the geranium, specialty herb and tropical plant nurseries are your best bet — read descriptions carefully, as labeling is inconsistent across retailers.
How to make citronella candles
Making your own citronella candles is straightforward and lets you control the oil concentration — which can be higher than many commercial products.
What you’ll need:
- Soy wax or beeswax flakes
- Citronella essential oil (pure, not fragrance oil)
- Candle wicks
- Heat-safe containers (mason jars work well)
- A double boiler or heat-safe pitcher in a pot of water
- A thermometer
Basic method:
- Melt wax to approximately 170°F using a double boiler. Avoid direct heat.
- Remove from heat and let cool to around 140°F.
- Add citronella essential oil at a ratio of about 1 ounce of oil per pound of wax — this is higher than most commercial candles and will perform better. Stir thoroughly.
- Pour into prepared containers with the wick centered and held in place with a pencil or wick holder resting across the top.
- Allow to cool undisturbed for several hours.
- Trim wick to about ¼ inch before the first burn.
For best repellent performance, burn in an enclosed or sheltered space with minimal air movement, and use multiple candles for larger areas.
The bottom line on citronella
Citronella is a legitimate, plant-derived insect repellent with real science behind it — in the right form. Topically applied citronella oil provides genuine, if short-duration, protection against mosquitoes and other insects. Candles offer modest, localized benefit in still air. The garden plant, while beautiful and fragrant, is not a passive mosquito barrier.
If you’re building a natural pest control strategy, citronella has a place in it — as a topical repellent, as part of a homemade candle, or simply as a fragrant garden plant you’ll enjoy crushing between your fingers on a summer evening. Just don’t rely on it to do the heavy lifting from a pot on your porch.
Frequently asked questions
Does the citronella plant keep mosquitoes away? Not meaningfully just by growing nearby. The plant needs to be disturbed — leaves crushed — to release its oils, and even then, the concentration is lower than commercial citronella oil. Plant it for fragrance and occasional use; don’t count on it as a passive repellent.
Is citronella the same as lemongrass? They’re related but different. Both belong to the Cymbopogon genus and share some aromatic compounds, which is why lemongrass is sometimes marketed as a mosquito repellent. True citronella grass (Cymbopogon nardus) has higher concentrations of the specific compounds used commercially. Lemongrass has some repellent properties but is not a substitute for citronella oil in terms of efficacy.
How long does citronella repellent last? Applied to skin, citronella-based repellents typically provide 30 minutes to two hours of protection depending on concentration and formulation. Reapplication is necessary more frequently than with DEET or picaridin.
Can you use citronella oil directly on skin? Diluted, yes. Pure citronella essential oil should be diluted in a carrier oil (like coconut or jojoba) before skin application — typically 10 to 20 drops per ounce of carrier oil. Undiluted essential oils can cause skin irritation. Always patch test first.
Does citronella work on ticks? Research on citronella as a tick repellent is limited. It is not currently recommended as a primary tick repellent; permethrin applied to clothing and EPA-registered repellents are more reliable options for tick protection.
