QUESTION: At a local nursery, I saw a mosquito plant. Does it actually repel mosquitoes? Also, are there any plants that are effective at repelling flying insects (flies, gnats, mosquitoes, etc.) from an area? — Earl Fox
ANSWER: With the zika virus prominent in the news, we’re all aware of mosquitoes this summer. Unfortunately, I’ve never found any research showing that plants can effectively be used to repel mosquitoes.
The plant most commonly sold as the mosquito plant or citrosa is a lemon-scented geranium. The lemony-scented essential oils in the plant do have mosquito-repellent properties. But the scent is not produced by the plant just sitting in an area. You can smell the fragrance only if you disturb the foliage physically, and even that will not drive mosquitoes out of an area.
For the best protection, you would have to rub the leaves of the plant on your skin to get any repellent benefit. And there are lemon-scented herbs that are more effective, including lemon thyme and lemon balm, which both contain more of the essential oils and are better choices.
So the plants you read about being “mosquito-repellent plants” will not keep the bugs out. However, burning or boiling the herbs may help repel mosquitoes from an area.
As for the herbs, before you rub them on your skin, check yourself for allergies. Rub a small area of your inner forearm a few times with the leaves. If there’s no skin reaction or redness the next day, it’s likely safe for you use these plants. Rubbing these on your skin will only provide a short period of protection. For the most effective, longest-lasting repellents, choose those containing Deet.
Here are some plants that have mosquito-repelling properties when rubbed on the skin:
– basil (Ocimum, especially lemon, cinnamon and African blue basil)
If there were actually plants that repelled mosquitoes just by being planted in a pot or in the ground, we would all have these plants in our landscapes and never be bothered by flying insects. But, sadly, this is not the case.
Dan Gill is a horticulturist with the LSU AgCenter.
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