Key Takeaways
- The commonly known Citronella plant or mosquito plant (Pelargonium citrosum) is widely believed to repel mosquitoes.
- However, studies have shown that the Pelargonium citrosum is not effective at repelling mosquitoes.
- The Citronella plant (Pelargonium citrosum) may have a lemon scent similar to Citronella grass, but it does not contain enough essential oils to effectively repel mosquitoes.
- The confusion arises because there are two different plants referred to as “Citronella plant”:
- Citronella plant (Pelargonium citrosum): Not effective at repelling mosquitoes.
- Citronella grass (Cymbopogon nardus and Cymbopogon winterianus): Effective in repelling mosquitoes, and in fact is the source of citronella oil used in mosquito repellents products like candles, lotions, and sprays.
- To naturally repel mosquitoes in your garden, consider planting other mosquito-repelling plants like Lavender, Marigolds, Basil, Rosemary, Mint, Lemongrass, and Garlic.
- While the Citronella plant (Pelargonium citrosum) is not effective at repelling mosquitoes, it can still be an attractive addition to your garden for its ornamental value.
- DEET is more effective in keeping mosquitoes away.
Table of Contents
Mosquitos are a nuisance and spread serious diseases, including West Nile and Zika virus in North America.
People seek innovative ways to repel mosquitos without relying on chemical deterrents like DEET.
Citronella torches and candles are popular alternatives, but the effectiveness of citronella plants as mosquito repellents is debated, especially in areas with high mosquito density.
Research suggests that citronella plants themselves do not repel mosquitos, as the insects do not distinguish between citronella and other plants like geraniums.
This article examines the citronella plant, its mechanisms, and its efficacy in deterring mosquitos.
Which Is The Real Citronella Plant?
The real citronella plant that repels flies come from the Cymbopogon plant family.
However, often marketed as mosquito repellents, “citronella plants” refer to the following two plants:
- Cymbopogon nardus (commonly known as Citronella Grass): This is a true citronella plant—a clumping grass that grows up to 6 feet tall and contains citronella oil, which is used in insect repellents. However, the plant itself does not release enough oil into the air to effectively repel mosquitoes.
- Pelargonium citrosum (commonly known as Scented Geraniums): These plants are often sold as “mosquito plants” or “citronella plants.” Crushed leaves emit a strong citronella-like scent, yet they lack significant citronella oil content. As a result, they are not effective in repelling mosquitoes.
Despite the marketing of both plants as mosquito repellents, their mere presence in a garden or on a patio does not significantly deter mosquitoes.
The most effective way to use citronella as a mosquito repellent is through products containing concentrated citronella oil, such as candles, torches, or sprays.
Where Does Citronella Oil Come From?
Citronella oil is derived from the leaves and stems of Cymbopogon, a genus of grass plants.
The two main species used for citronella oil production are Cymbopogon nardus, also known as Ceylon citronella, and Cymbopogon winterianus, known as Java citronella.
These plants are native to tropical regions of Asia, such as Sri Lanka, India, and Indonesia.
How Do You Extract Citronella Oil?
Extracting citronella oil involves the use of steam distillation.
Steam distillation: a process that exposes the plant material to steam and causes the oil to evaporate, extracts the oil.
Steam distillation creates vapor; the vapor is then cooled and condensed back into a liquid form, yielding the essential oil.
Due to its distinctive scent and insect-repelling properties, Citronella oil finds common use in insect repellents, candles, and other products.
Do Citronella Plants Really Repel Mosquitoes?
Citronella plants do not effectively repel mosquitoes by simply growing in a garden or placed on a patio.
While these plants contain insect repellent compounds, the amount released into the air is insufficient to provide significant protection against mosquito bites. Studies have shown that citronella plants do not significantly reduce mosquito populations or prevent mosquito bites.
There are relatively few studies that have been carried out to determine the efficacy of essential oils from citronella as arthropod repellents.
Citronella-based repellents only protect from host-seeking mosquitoes for about two hours although the formulation of the repellent is very important.
The second way to use volatile plant repellents is to continuously evaporate them.
Source: United States National Library of Medicine and National Institutes of Health
Is It Worth It To Grow Your Own Citronella Plants to Repel Flies?
No, it’s probably not worth growing your own citronella plants.
Growing your own citronella plants is not an effective way to repel mosquitoes in outdoor areas. Citronella plants, such as Citronella Grass (Cymbopogon nardus) and Scented Geraniums (Pelargonium citrosum), do not release enough citronella oil into the air to effectively deter mosquitoes.
While these plants may produce a citronella scent when the leaves are crushed, they do not provide a sufficient concentration of citronella oil to repel mosquitoes in a garden or patio setting.
For effective mosquito control, it is better to use products containing concentrated citronella oil, such as candles, torches, or sprays, or to opt for other proven mosquito repellent methods.
FAQ
Is Citronella Oil Toxic?
According to the information provided by the National Pesticide Information Center, the oil of citronella has low toxicity. It can cause mild skin and eye irritation and may trigger allergic reactions in some individuals with prolonged or frequent exposure. If ingested, it may lead to coughing or throat irritation. However, citronella oil is generally non-toxic to birds and only slightly toxic to fish and other aquatic organisms. Its low toxicity and usage patterns make it unlikely to harm wildlife. The Environmental Protection Agency classifies citronella oil as a minimum-risk pesticide.
Do Citronella Candles Actually Repel Mosquitoes?
Citronella candles are not an effective method for repelling mosquitoes in outdoor settings according to researchers at the University of Guelph in Ontario, Canada that conducted a study to investigate the effectiveness of citronella candles in repelling mosquitoes. The study found that candles only reduced the number of mosquitoes by 13% in a 1-meter radius around the candle, which is not statistically significant. The researchers concluded that citronella candles do not provide adequate protection against mosquito bites, and that other methods, such as DEET-based repellents or protective clothing, are more effective in preventing mosquito bites.
Are Citronella Plants More Effective Than DEET in Repelling Mosquitoes?
Citronella plants are not more effective than DEET in repelling mosquitoes. DEET is a synthetic chemical that has been proven to be one of the most effective mosquito repellents available. It works by disrupting the mosquito’s ability to detect and locate potential hosts. In contrast, citronella plants, such as Citronella Grass and Scented Geraniums, do not release enough citronella oil into the air to effectively repel mosquitoes.
References
Lindsey Hyland grew up in Arizona where she studied at the University of Arizona’s Controlled Environment Agriculture Center. She continued her gardening education by working on organic farms in both rural and urban settings. She started UrbanOrganicYield.com to share gardening tips and tactics. She’s happy to talk about succulents and houseplants or vegetables and herbs – or just about anything in a backyard garden or hydroponics garden.