Mosquitoes and other insects are a worldwide problem, especially in the spring and summer. Mosquitoes, in particular, are the bane of many a summer barbecue. Luckily, there are numerous methods to help fight these obnoxious creatures.
However, many contain synthetic chemicals and ingredients that are toxic to animals besides pests, including beneficial insects and even mammals (like humans). In humans, the most common side effects of mosquito repellents are allergic reactions and rashes. But it can also lead to headaches, dizziness, and even seizures.
One alternative to synthetic products is natural insect repellents. These can still cause allergic reactions and may be toxic. Always exercise caution when trying a new product or plant. Here, we provide an overview of the most popular plants that deter mosquitoes.
Plants that repel mosquitoes
Cymbopogon, or lemongrass, is a genus in the grass family. The species lemongrass, Cymbopogon citratus, is native to India and Sri Lanka. It is an introduced species in tropical and subtropical regions of the Americas, Africa, and parts of Asia, among others. Its primary uses are culinary, medicinal, ornamental, and as a source of essential oils. Lemongrass gets its name from the strong lemon scent of its leaves. It grows in tall, wide bunches, with leaves up to 2 meters tall in 1-meter wide tufts.
Lemongrass is widely used in medicine due to its antibacterial, antifungal, anti-inflammatory, and antimicrobial qualities. It can help lower cholesterol, potentially preventing cardiac issues and diseases.
Lemongrass has been shown to destroy many kinds of cancer cells, without harming healthy cells. This provides a potential non-toxic alternative to chemotherapy. It is further used to treat stomachaches and gastric ulcers. Lemongrass can even help reduce anxiety and relieve insomnia. Despite these health benefits, more research is needed before lemongrass extracts can become part of the medicinal mainstream.
Lemongrass repels mosquitoes and other insects. It can be toxic to some predatory beneficial insects, however, so use it with caution. Because it deters mosquitoes, it also helps to prevent diseases transmitted by mosquitoes, including malaria.
You can plant lemongrass in your yard or garden, but it will not just repel mosquitoes where it’s planted. It must release its oils. The easiest way to do this is to crush the leaves. You can even apply the oil to your skin as a repellent, but be sure to test for allergic reactions first. Rub a tiny amount on your inner forearm a few times a day. If you don’t feel irritation or see redness, you’re likely safe. To be extra safe, consider purchasing a commercial product with lemongrass oil in it rather than putting concentrated lemongrass oil on your skin.
Citronella grass, Cymbopogon nardus, is a species of lemongrass. It is a tropical/subtropical grass native to southeast Asia and parts of Africa. It has been introduced to the Americas, where it is grown as an ornamental and for its oil. You can grow it in yards and gardens in warm regions. In colder regions, it grows as an annual. Like lemongrass, citronella grass grows tall and wide and its oil is a mosquito repellent.
Commercial insect repellents often contain citronella oil. These products aren’t as effective as advertised, however. Citronella’s major effect is to mask the human scents that attract insects rather than actively repelling insects. Recent studies have found that citronella candles and citronella wristbands do not work well against mosquitoes. Citronella oil is also an ingredient in pet flea collars and flea shampoos, though its effectiveness against fleas is questionable.
Citronella further has antifungal, anti-inflammatory, antioxidant, and antimicrobial properties. It reduces the proliferation of cancer cells. It is used in traditional medicine to reduce fever and is thought to alleviate stress. You can also use it as an antiseptic for cleaning surfaces.
A plant similar to citronella is citrosa, Pelargonium citrosum, also known as the mosquito plant. Though advertised to protect against mosquitos, it is ineffective.
Pelargonium is a genus of plants called geraniums (or simply pelargoniums) that are often confused with the genus Geranium. Both are in the family Geraniaceae. There are over 280 species of Pelargonium. Their flowers differ in color. While commonly white or pink, some have black flowers. Pelargoniums are native to Africa, Asia, and Australasia. They are a low-maintenance garden plant requiring full sun in the spring and summer. They cannot tolerate overwatering or frost. You can grow them as annuals in colder regions or bring them inside during the fall and winter.
The oils of Pelargonium act as insect repellents. These oils have strong scents that you can release by brushing against the leaves. Different species have different scents, including evergreen, peppermint, lemon, rose, and apple. In addition to the varied fragrances, pelargonium plants have beautiful blooms, making them a beautiful and decorative addition to your garden. This plant repels cabbage worms and Japanese beetles. In commercial products when combined with glycerin, lecithin, vanillin, coconut oil, and soybean oil, geranium oil can be as effective against mosquitoes as DEET-based products. In addition to mosquitoes, geranium oil repels ticks.
Coleus is a genus of an annual plant, popular for its colorful leaves. They grow best in partial shade but some newer varieties can grow in full sun. Coleus plants are easy to grow. However, they are neither drought-, overwatering-, nor frost-tolerant. They are native to warm regions of Asia so will grow best in hot climates.
One of the reasons coleus is easy to grow is that it is resistant to many pests and diseases. Keep an eye out for mealy bugs, aphids, whiteflies, and rot, though. Not only are insect pests deterred by coleus, but one species, Coleus canina, also repels cats. This species helps prevent garden damage by cats because its scent, while essentially undetectable by humans, is unpleasant to cats.
Horsemint (Monarda punctata), also called spotted beebalm, is a perennial, flowering mint that grows in clumps. Its light-colored flowers (ranging from purple to yellow to green) make it a pretty ornamental garden plant.
Horsemint is drought-tolerant and requires full or partial sun. It grows in sandy soils and reaches heights over 1 meter. Its leaves have a distinct oregano scent and its flowers attract butterflies, bees, moths, and hummingbirds.
Horsemint is also medicinal. For example, its leaves can be crushed and steeped in cold water to alleviate backaches. It is also used against fever, inflammation, and chills.
Its oils, in addition to being mosquito repellents, have antibacterial properties and can be used against respiratory bacteria, including Streptococcus. A component of horsemint, thymol, in an important ingredient in mouthwash.
Tiger grass (Centella asiatica), also called spadeleaf, is a tropical to subtropical perennial. It grows in moist habitats, often wetlands, so it is not drought-tolerant and perhaps not an ideal garden plant. Furthermore, mosquitoes lay their eggs in standing water, so keeping a wetland plant in your yard may be mildly counterproductive. Not technically a grass, tiger grass is a creeper with kidney-shaped leaves.
Common in Asia, tiger grass is a culinary herb and used in cosmetics and traditional medicine. Its medicinal uses include the treatment of wounds, diarrhea, fever, anxiety, depression, and skin conditions such as eczema. It has anti-inflammatory, antibacterial, and antiviral properties.
In addition, it’s on this list because its leaves contain substances that kill mosquito larvae (the extracts showed larvicidal action against three different species of mosquitoes). Its essential oils act as a mosquito repellent. Like the other plants on this list, it will not repel mosquitoes simply by growing in the garden. You must release the oils by crushing the leaves.
In the spring, when you start preparing your garden, consider including the plants on this list. Not only would the ornamentals be a decorative addition to your garden, but you’ll also have a ready supply of oils to use for repelling mosquitoes.
In order to get the most out of your mosquito-repellent plants, plant them near your patio, deck, and other outdoor spaces and near entrances. This will ensure you brush against the plants when you’re spending time outside or as you leave your house.
If you choose one of the culinary plants, it will also be convenient to have it growing close to the house for easy access when cooking. Some also have a pleasant scent that will enhance the enjoyment of your outdoor spaces. A few of the plants mentioned above are safe to apply directly to your skin. However, if you have sensitive skin, you can also carry fresh, crushed leaves in your pockets. The oils will still be detectable by mosquitoes.
For maximum effectiveness, make sure that your yard isn’t attracting mosquitoes in the first place. Also, get rid of any standing water. This includes keeping pots turned upside down to prevent them from collecting rainwater, filling in puddles, and regularly changing the water in birdbaths. Be sure to fix any leaky outdoor faucets. Turn off the water supply to hoses when you’re not using them.
If you’re not into gardening, there are many commercial products that contain oils from these plants. Just remember, citronella candles and wristbands don’t work well.
There are many alternatives to synthetic chemical products. Give these insect-repellent plants a try if you’re looking for something more natural that can also enhance your garden.