Written by: Karin Apfel
Super insect-repelling plants to have around the barn.
Grow these around your house and barn to repel biting insects such as mosquitoes and ticks. Crush the leaves and stems, and you have a handy, short-acting repellant to put on your skin. You can even make a repellant spray by crushing the plants, soaking them in water, then straining out the plant matter. All 10 of these plants are safe to grow around pets and children, but ingestion of substantial amounts should still be avoided.
Often planted in vegetable gardens to repel harmful insects, marigolds contain pyrethrum, a compound used in many commercial repellants. Studies have shown that essential oils derived from these plants offer a protection time of roughly half that of DEET, two to three hours.
Not only will your cats thank you, but this lowly weed contains nepetalactone, which can repel mosquitos up to 10 times more effectively than DEET according to one study. It is highly invasive, so plant it only where you don’t mind an extensive patch of it and a possible gathering of all the local moggies.
The citrosa plant (commonly known as citronella) carries the citronella fragrance in its foliage, which mosquitos, in particular, have some distaste for. It also smells nice to humans so is often grown in gardens or pots near the home.
As one of the most pungent of the culinary herbs, basil makes an excellent natural insect repellant. A 2011 review published in the Malaria Journal found that the essential oils from Ocimum (aka basil) provided high levels of mosquito protection largely due to the chemical eucalyptol (cineole).
A drought-resistant plant with a pleasant (to humans) aroma is lavender. Historically used to repel moths via dried flower sachets, it can deter mosquitos and is also used in many herbal tick repellants.
Another culinary herb, rosemary was used in wedding ceremonies during the Middle Ages and was traditionally referred to as a love charm. In fact, it was more likely used to repel the fleas that infested clothing and bedding in the day. This property was due to the presence of camphor in rosemary which is toxic to many insects.
Sweet-smelling peppermint oil has a high concentration of natural pesticides, mainly pulegone as well as menthone and cineole (see basil). It has shown to be effective as a larvicide for mosquitos, killing within 24 hours of exposure to a solution of peppermint and water.
On the more pungent side of insect deterrents is garlic. Ingestion is neither useful nor advised for insect control (it can cause anemia in horses). However, garlic oil diluted in water is a decent insecticide so can work to kill fleas and mites. And, of course, repel vampires.
Scented geraniums contain geraniol a compound similar to citronella, that has short-term mosquito repellant properties and has been successfully tested on the mosquito species that carry West Nile virus.
10. Lemon Balm
Another invasive member of the mint family, lemon balm or balm mint attracts bees and butterflies while repelling mossies. It contains both citronellal and geraniol and is often used in homemade repellants since it is very safe when applied topically.