Though it natively thrives in USDA hardiness zones 10 and 11, lemongrass is a fibrous natural mosquito repellant candidate that provides a productive portfolio of additional properties. Scientifically known as Cymbopogon citratus, this plant is best known for its inclusion as an ingredient in Asian cuisine as well as for its natural inclusion of citronella compounds ideal for blocking mosquitoes from biting (1).
While the lemongrass plant can be useful on its own, most scientific studies have studied this plant in its derivative essential oil form. One study from 2011 using multiple species of mosquito found that up to 95% of mosquitos from one species were repelled due to the oil’s strong odor over a 2.5 hour period (2).
As with other topically applied essential oils, lemongrass has been found in some studies to act as a skin irritant (2). While this result was not common, it was likely caused by a degree of acidity found within the essential oil form itself.
When choosing between lemongrass and other plant-based mosquito repellants, lemongrass is often one of the best options for gardeners who are just beginning to experiment. This is because lemongrass is fairly easy to grow and produces a great volume of its productive leaves in a single annual growing season.
When it comes to actually using lemongrass, nearly all current users agree that the best method for application is by crushing the leaves and then applying the oily mixture directly to the skin. In regulated conditions (where the user is not sweating), protections from lemongrass oil can last several hours, while sweat can easily degrade its effective lifespan by more than half.
Also, current users caution against immediately applying lemongrass oil to the entire body upon first use. Instead, they recommend applying it to a single small area of the body in order to evaluate whether your body not will mount an allergic reaction against its topical presence. If this occurs, lemongrass will not be a good option to you, nor will any plants that contain citronella oil.
Forms of Lemongrass & Where to Get Them
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Plants
As noted, lemongrass plants are fairly versatile and hearty when it comes to mosquito repellant plants. As an herb at heart, this plant flourishes best in moist soil that has been supplemented with a substantial layer of nutrients (manure is ideal). In terms of spacing, consider placing your new lemongrass plants up to 24 inches apart to accommodate for their outward growth pattern (3).
When harvesting a lemongrass plant, consider making two separate bins based on its primary uses. If you intend to use your lemongrass for its essential oil, separate its leaves (with caution, as they tend to be sharp) and crush them as soon as possible in order to obtain its essential oil. However, those looking to use lemongrass for its cooking ingredient qualities will need to withdraw the bulbous base, clean it, and keep it cold until use.
If you are looking to plant some lemongrass of your own, you can often pick up live starters such as these online. You may also consider looking at a plant nursery in order to find the best candidate for your garden.
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Essential Oils
As noted, lemongrass’ essential oil is the key component when it comes to deterring mosquitoes from biting. While this hasn’t been attributed to a single compound, general consensus states that this property can be attributed to its “lemony” scent (which can be directly experienced when smelling the oil or boiling lemongrass leaves to make a tea). This scent then overpowers a mosquito’s olfactory nerves, causing the scent to “camouflage” your presence from the mosquito’s perspective.
Lemongrass oil is broadly available, including through online sources such as this.
Sources
1 – Leite JR, Seabra Mde L, Maluf E, et al. (July 1986). “Pharmacology of lemongrass (Cymbopogon citratus Stapf). III. Assessment of eventual toxic, hypnotic and anxiolytic effects on humans”. J Ethnopharmacol. 17 (1): 75–83. doi:10.1016/0378-8741(86)90074-7
2 – Marta Ferreira Maia and Sarah J Moore. Plant-based insect repellents: a review of their efficacy, development and testing. Published online 2011 Mar 15. doi: 10.1186/1475-2875-10-S1-S11
3 – How-To: Growing Lemongrass – Bonnie Plants
Other Plants & Herbs as Mosquito Repellents
Checkout our analysis of other plants & herbs as natural mosquito repellents: