Do Mosquito-Repellent Plants Really Work?
By Chris Williams on June 17, 2016.
With all the concern lately about mosquito-transmitted diseases, there seems to be some heavy marketing on the part of plant nurseries and garden stores to sell “mosquito-repellent plants” for your home and yard. The claim is that you can simply put pots of these repellent plants anywhere that you don’t want mosquitoes and your family will be protected from bites.
Folks, it doesn’t work that way. A plant sitting in a pot is going to have no effect at all on hungry mosquitoes. What they don’t tell you is that to get mosquito repellent properties from that plant you have to process it to release its essential oils. That means, at the minimum, crushing or boiling and extracting oils from the leaves or flowers. Mosquitoes are not going to get a whiff of that potted plant and head in the other direction. In fact, they might use the plant as a resting site.
There is a huge long list of nursery-grown plants that now claim mosquito-repellent properties including the well known citronella, lemon balm, catnip, even lavender and basil. Most sellers never mention that the plant, as is, is not repellent. In fact, they infer just the opposite. One site said to “place a pot of marigolds anywhere in the garden where you want a mosquito-free zone.”
You Want Repellency? Prepare to Crush, Boil and Extract!
At least one website offered close to the correct way to utilize mosquito-repellent plants: For citronella, you have to crush the leaves to get the essential oil. (That could take a lot of citronella.) For catnip, boil the flowers to make a spray. For lemon balm, crush the leaves and rub them on your skin. Even if you manage to extract the essence from the plant, there is no information on how much you need to apply or how long you can expect any repellent properties to last.
Be Safe. Follow Expert Recommendations Instead
If you like the plant for its appearance, buy it. Otherwise spend your money on legitimate insect repellents instead. This is not the time to experiment with off-the-wall repellents. The Centers for Disease Control gives a high recommendation to only 4 different insect repellent ingredients. These are all considered to be highly protective against mosquitoes for hours if you buy a product with at least 20-30% of the repellent by volume. The old standby DEET is still considered to be the best repellent ingredient. The other three are picaridin, IR3535, and oil of lemon eucalyptus. Notice that it’s OIL of lemon eucalyptus — that proves the point!
For a list of brand name products that contain these ingredients, as well as the right way to use insect repellents, see CDC’s fact sheet on insect repellents.