Using plants to get rid of mosquitoes is a wonderful idea, but it can be difficult to separate folklore from truth. Many plants commonly believed to be mosquito repellents, such as marigold and citrosa, are not as effective as people might believe, possibly because they are used incorrectly. Most plants need to be crushed or infused to release chemicals that repel mosquitoes. Even then, they do not appear to be as effective as chemical repellents such as DEET. Does this Spark an idea?
Plants With Essential Oils
Essential oils are concentrated liquids containing aromatic compounds derived from plants. Of all essential oils, only two are registered mosquito repellents with the U.S. Environmental Protection Agency: citronella and lemon eucalyptus. Oil of citronella is extracted from citronella grass (Andropogon nardus). But citronellal, one of the main ingredients in citronella oil, can be found in several species of lemongrass (Cymbopogon spp.), lemon thyme (Thymus X citriodorus) and lemon balm (Melissa officinalis). Crushed leaves of these plants are moderately effective at repelling mosquitoes when rubbed on skin.
Aromatic Plants
A number of aromatic plants have the reputation of being mosquito repellents. This list includes birch, cinnamon, cedar, geranium, pine, thyme, lavender, sage, spearmint and yarrow. Although there is no scientific proof that these plants or essential oils derived from these plants repel mosquitoes, they are often the primary ingredient in botanical mosquito repellents. According to Colorado State University Cooperative Extension, you can place drops of these essential oils in your hair and on your body to help repel mosquitoes. It also recommends a 50-50 infusion of chamomile and elder leaves. Infusions are made by pouring boiling water on the herbs and letting it steep for 15 minutes. Strain the liquid and use it as a repellent.
Catnip
The essential oil of catnip (Nepeta cataria) contains nepetalactone. Nepetalactone gives the plant its characteristic odor and, according to a research group at Iowa State University, is 10 times more effective at repelling mosquitoes than DEET, the chemical found in most mosquito repellents. However, follow-up studies have shown that catnip works better on some species of mosquitoes than others, according to the University of Wisconsin at Madison.
Companion Planting
Companion planting is when two or more plants are placed next to one another to improve the quality of crops and soil. It is also a natural way to repel insects, including mosquitoes. According to Cornell University Cooperative Extension and the Alabama Cooperative Extension Service, planting tomatoes and basil together repels mosquitoes, flies and hornworms. Use approximately three basil plants for each tomato plant. The Alabama Cooperative Extension Service also recommends planting roses and pennyroyal together. This pairing repels mosquitoes, flies, fleas and other insects.
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