12 Plants That Repel Unwanted Bugs

2022-06-25 04:15:28 By : cheng iris

Insects have one of the most important ecological roles in nature, but you must admit: Bites from mosquitoes, gnats, flies, and no-see-ums are highly annoying. To prevent their itchy and painful punctures, many slather themselves in chemical insect spray (DEET, one of the worst offenders, is neurotoxic and has been detected in groundwater). They don't know they can repel bugs—at least partially—with plants.

Learn about 12 plants that could help you manage the mosquito population in your garden. As a bonus, you can use most of them to make your own natural bug repellent.

The smell of some herbs and flowers, resulting from the distribution of tiny globules that contain essential oils, can help ward off bugs. High temperatures can cause the globules to become volatile, evaporating the essential oils and turning them into vapors. The many globules on the underside of rosemary leaves are one of the best examples of this.

Disclaimer: This probably isn't enough to make your garden totally insect-free. Dr. Bodie Pennisi, a professor and landscape specialist at the University of Georgia's Griffin campus, says it's unclear how many plants would be needed to effectively repel insects and how close together they would need to be planted. But who would want a bug-free garden, anyway, when bugs are food for so many birds and other beneficial critters?

One of the best things people can do to hold down mosquito populations, she advises, is to eliminate any standing water, which is where mosquitoes breed.

Some of the plants on this list are toxic to pets. For more information about the safety of specific plants, consult the ASPCA's searchable database.

Basil as a plant is particularly effective against a certain pest called the flea beetle (and the cabbage webworm, a non-insect). It also contains four volatile compounds that could deter mosquitoes: estragole, citronellal, limonene, and nerolidol.

You can also use fresh basil to make an insect repellent spray. A simple recipe calls for pouring four ounces of boiling water into a container with four to six ounces of fresh basil leaves, stems attached. Let the leaves steep for several hours, remove the leaves, and squeeze all of the leaves' moisture into the liquid. Then thoroughly mix four ounces of vodka into the basil-spiked water. Store in the refrigerator and apply as a spray when going outdoors, making sure to keep the spray away from your eyes, nose, and mouth.

Humans are generally attracted to the smell of lavender, but mosquitoes, flies, and other unwanted insects aren't. Lavender essential oils have an 80.9% repellency effect against the mosquito species Anopheles stephensi.

Place tied bouquets around your house to help keep flies out. Plant it in sunny areas of the garden or near your home's entryways to help keep these areas pest-free. You can also use oil extracted from the flowers as a natural mosquito repellent. As a bonus, lavender oil nourishes the skin and has a calming effect.

You've no doubt seen citronella used in conventional mosquito repellents (usually in candles). This natural oil is found in lemongrass, an ornamental that can grow up to four feet tall and three feet wide in one season. Studies have shown that this plant has a 100% repellency effect against Anopheles culicifacies, one malaria-carrying species of mosquito, and is highly effective against others, too.

It's worth noting that lemongrass isn't just the name of one plant; it's the umbrella name for plants in the Cymbopogon family, which also includes citronella grass. This grass—with many culinary uses—is hardy only in South Florida (USDA Plant Hardiness Zone 10) and grows as an annual everywhere else. It does well in a pot or in the ground in a sunny, well-draining location.

This hardy herb has been shown to repel mosquitoes, but only when crushed. One professor, Dr. Donald Lewis of Iowa State University's Department of Entomology, once said the plant has 62% the repellency of DEET. To release its citronellal, you must first bruise the leaves. To do this, simply cut off a few stems and rub them between your hands.

The plant can adapt to dry or rocky, shallow soil and will thrive in your herb garden, a rock garden, or a front border as long as these are in sunny locations.

Thyme oil can cause skin irritation for those sensitive to plants in the mint family (such as sage, lavender, and oregano). Before adopting as an insect-repellant, determine your tolerance by rubbing crushed leaves on a small area of your forearm for several days to ensure no side effects occur. Thyme oil should also be avoided during pregnancy.

The smell of mint repels mosquitoes. The aromatic properties found in the leaves are also present in the stems and flowers. With a little work, the plant's oils can be extracted and combined with apple cider vinegar and cheap vodka (or witch hazel) to make a mosquito repellent. Containers of mint strategically placed in the garden or on the patio could help keep nearby plants insect-free.

Mint is best grown in pots rather than the ground because it spreads aggressively. Once established in the garden, it can be difficult to remove.

Rosemary's oils are as delicious to home cooks as they are unpleasant to many insects. The plant itself and its cuttings are both effective repellents. You can make a simple spray by boiling one quart of dried rosemary in a quart of water for 20 to 30 minutes, then straining the liquid into a container containing a quart of cool water. Store the DIY repellent in the refrigerator and discard when it no longer smells like rosemary.

Rosemary is available in various forms. Plants can be grown in containers on a patio and shaped into ornamental pyramids, grown in herb gardens, or planted in landscaped beds, where some varieties can grow quite large.

A member of the mint family, catnip contains a chemical called nepetalactone, which attracts cats and repels insects such as mosquitoes, flies, deer ticks, and cockroaches. It reportedly triggers a chemical receptor in insects that creates the sensation of pain or itching.

Catnip plants are relatively easy to grow. You can plant from seeds or as plants outdoors in the spring or fall. It grows to three or four feet tall and blooms small lavender flowers. Be careful, however, as catnip can become invasive and take over your garden.

Jacky Parker Photography / Getty Images

Plants in the allium family—such as the dramatic Allium giganteum, which grows stalks up to six feet tall—have been regarded as a broad-spectrum natural insecticide throughout Indigenous history. They are said to repel insects like aphids and carrot flies that plague vegetable gardens.

Plants that will benefit from being planted with alliums include tomatoes, peppers, potatoes, cabbage, broccoli, kohlrabi, and carrots. Alliums include small-growing herbs such as chives and garlic chives, leeks, and shallots. They're edible, and they're great for keeping aphids off rose bushes.

Chrysanthemums are effective against roaches, ants, Japanese beetles, ticks, silverfish, lice, fleas, bedbugs, spider mites, harlequin bugs, and root-knot nematodes. They contain pyrethrum, which can kill flying and jumping insects. In fact, pyrethroids—compounds synthesized from chrysanthemums—are used in many conventional home and garden insecticides and are frequently used in indoor sprays, pet shampoos, and aerosol bombs.

However, pyrethroids are known to have harmful effects on aquatic ecosystems, birds, and non-target insects. By planting chrysanthemums in your garden and relying on their natural pyrethrum, you can receive the same insect-repelling advantage without the harmful effects.

The edible nasturtium reportedly repels whiteflies, squash bugs, aphids, many beetles, and cabbage loopers. These flowers release an airborne chemical that repels predacious insects, protecting not just the nasturtium but also other plants in the grouping. Because many of the insects nasturtiums repel favor vegetables—tomatoes, cucumbers, kale, kohlrabi, collards, etc.—this plant is great to use along the edges of vegetable gardens. Fortunately, nasturtiums do not repel the all-important pollinator, the bumblebee.

Floss flowers contain coumarin, a chemical used in some commercial insect repellent sprays. Mosquitoes don't like the smell of this chemical, also found in sweetgrass. Not only do they help keep biting bugs at bay; they're also notably ornamental, producing blue, pink, and white blooms in the summer and fall.

Floss flowers do best in fertile soil in rock gardens, flower beds, or as an edging plant.

Pitcher plants, comprising the largest group of carnivorous plants, trap and ingest insects. These exotic-looking plants lure insects into their "pitcher," actually a specialized leaf, through a combination of nectar, fragrance, and color. Once inside the pitcher, insects find themselves on a slippery surface with downward-facing hairs. They then fall into a pool of water and drown or die from exhaustion, becoming food for the plant.

Critters that most often fall prey to North American pitcher plants are ants, flies, wasps, bees, beetles, slugs, and snails. Pitcher plants, which grow in bogs in the wild, need a sunny, moist area, which is generally a difficult combination for home gardeners. Growing them in pots that sit in saucers of water is easier.

To check if a plant is considered invasive in your area, go to the National Invasive Species Information Center or speak with your regional extension office or local gardening center.

 U.S. Department of Health and Human Services. "Toxicological Profile for DEET (N,N-DIETHYL-META-TOLUAMIDE)." Centers for Disease Control. 2017.

Kianmatee, Supawan, and S.L. Ranamukhaarachchi. "Pest Repellent Plants for Management of Insect Pests of Chinese Kale, Brassica oleracea L." International Journal of Agriculture and Biology. 2007.

Asadollahi, Amin, Mehdi Khoobdel, Alireza Zahraei-Ramazani, Sahar Azarmi, and Sayed Hussain Mosawi. "Effectiveness of plant-based repellents against different Anopheles species: a systematic review." Malaria Journal. 2019.

Auerbach, Paul S. "Wilderness Medicine (6th Edition)." Elsevier Science. 2016.

Lewis, Dr. Donald. "Mosquito Repellent Plants." Iowa State University Department of Entomology. 1993.

Maia, Marta Ferreira, et al. "Plant-based insect repellents: a review of their efficacy, development and testing." Malar J. 2011, vol. 10, S11, doi:10.1186/1475-2875-10-S1-S11

Ayu Manik Pratiwi, Maharani, and Purwati. "The Repellent Activity Test of Rosemary Leaf (Rosmarinus officinalis l) Essential Oil Gel Preparations Influence on Aedes aegypti Mosquito." Journal of Physics: Conference Series. 2021.

Melo, Nadia. "The irritant receptor TRPA1 mediates the mosquito repellent effect of catnip." Current Biology. 2021.

"Companion Plant Chart." Keweenaw Bay Indian Community.

Simon, Terri. “Borders in Your Garden: Friend of Foe?” Texas A&M Agrilife Extension. 2018.

Hénault-Ethier, Louise, MSc. "Health and environmental impacts of pyrethroid insecticides: What we know, what we don’t know and what we should do about it." Équiterre. 2016.

Faires, Nicole. "The Ultimate Guide to Natural Farming and Sustainable Living Permaculture for Beginners." Skyhorse Publishing. 2014.

Milne, Marc, et al. “Carnivorous pitcher plants eat a diet of certain spiders, regardless of what's on the menu.” Ecosphere. 2018, doi:10.1002/ecs2.2504

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