Home & Garden Garden 16 Plants That Repel Unwanted Insects By Tom Oder Writer Furman University. Tom Oder is a writer, editor, and communication expert who specializes in sustainability and the environment with a sweet spot for urban agriculture. our editorial process Twitter Twitter Tom Oder Updated September 09, 2020 Fact-checked by Betsy Petrick Fact Checker Ohio Wesleyan University Brandeis University Northeastern University Betsy Petrick is an experienced researcher, writer, and producer. Our Fact-Checking Process Article fact-checked on Oct 19, 2020 Betsy Petrick Treehugger / Steven Redmond Share Twitter Pinterest Email Home & Garden Planting Guides Indoor Gardening Urban Farms Insects Are you an insect magnet? If you aren't, you probably know one. Insect magnets attract annoying insects the second they walk outdoors — or so it seems. If this describes you, take comfort in knowing that one of the ways you can fight back against mosquitoes, gnats, flies, no-see-ums and other pesky bugs doesn't have to involve covering yourself with a sticky spray or engaging in chemical warfare. To help you enjoy going outdoors, try strategically placing insect-repelling plants in your garden or on your patio. Essential oils in these plants act as nature's bug repellent. Insects tend to avoid them. You can even use some of these plants to make your own natural bug repellent. But know that simply including insect-repelling plants in your landscape will not in itself ensure your garden is insect free. "There's not enough research in this area to support that," says Dr. Bodie Pennisi, a professor and landscape specialist at the University of Georgia's Griffin campus. "The concentration of oils is not there to offer that kind of protection." There may be fewer insects, but no one's done the research into how many plants, planted how close together, would be effective in repelling insects to any great extent, says Pennisi. 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. For those who would like to give the natural route a try, we've described some easy-to-find herbs readily available at most nurseries that are said to repel mosquitoes and other annoying insects. The smell from fragrant herbs is the result of the distribution of tiny globules that contain oils. High temperatures, for example, can cause the globules to become volatile, evaporating the essential oils and turning them into vapors, Pennisi says. The many globules on the underside of rosemary leaves (seen above) are one of the best examples of this. We've included our take on ornamental flowers that can help keep plant-attacking insects at bay. Keeping your growing areas as insect free as possible will help your vegetable garden stay productive and your ornamental beds attractive. In addition, we've included a carnivorous plant that eats insects which you can also include in your eco-friendly insect barrier. First, the herbs Basil Treehugger / Steven Redmond Repels house flies and mosquitoes. Plant basil in containers by your house doors and in outdoor areas where you like to relax or entertain. Basil is delicious in salads, in many pork and chicken recipes and with a variety of soups. Basil also improves the flavors of certain vegetables, include tomatoes, peppers and asparagus. You also can use fresh basil to make an insect repellent spray. A simple recipe calls for pouring four ounces of boiling water into a container holding four to six ounces of clean, fresh basil leaves (stems can be attached), letting the leaves steep for several hours, removing the leaves and squeezing all of the leaves' moisture into the mixture. Then thoroughly mix four ounces of (cheap!) vodka with the basil-water mixture. Store in the refrigerator and apply as a spray when going outdoors. Be sure to keep the spray away from your eyes, nose and mouth. Lavender Place dried lavender is bundles to keep flies out of your home. Tatiana Mihaliova/Shutterstock Repels moths, fleas, flies and mosquitoes. Lavender has been used for centuries to add a pleasantly sweet fragrance to homes and clothes drawers. Although people love the smell of lavender, mosquitoes, flies and other unwanted insects hate it. Place tied bouquets in your home to help keep flies outdoors. Plant it in sunny areas of the garden or near entryways to your house to help keep those areas pest free. You can also use oil extracted from the flowers as a mosquito repellent you can apply to exposed skin when going into the garden or patio. The Everything Lavender website has a guide for extracting the oil and making a lavender-infused body oil. Added benefits are that lavender oil nourishes the skin and has a calming effect that induces sleep. Lemongrass Lemongrass contains citronella, a natural oil often found in insect-repelling candles. Zulashai/Shutterstock Repels mosquitoes. You've no doubt seen citronella candles in stores during the summer and read how citronella will keep mosquitoes away. Citronella is a natural oil found in lemongrass, an ornamental that can grow up to four feet tall and three feet wide in one season. (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 wonderful culinary uses is hardy only in South Florida (Zone 10), so almost everyone else will have to grow it as an annual. It does well in a pot or in the ground in a sunny, well-drained location. Use its fragrant, narrow leaves in chicken and pork dishes and to flavor soups and salad dressing. Many Asian recipes call for lemongrass. Lemon thyme Bruise the leaves on this hardy plant to repel mosquitoes. Andrea_44 [CC BY 2.0]/Flickr Repels mosquitoes. This hardy herb 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. The plant itself will not repel pesky mosquitoes. To release its chemicals, you must first bruise the leaves. To do this, simply cut off a few stems and rub them between your hands. Before you do that, though, it's advisable to make sure the plant's natural properties will not adversely affect you. Determine your tolerance by rubbing crushed leaves on a small area on your forearm for several days. Mint Repels mosquitoes. 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. Cuttings of mint in mulch can help broccoli, cabbage and turnips. The leaves are commonly used to flavor minty iced tea. The aromatic properties found in the leaves are also present in the stems and flowers. With a little work, the plant's aromatic 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 will help keep nearby plants insect free. Rosemary Treehugger / Steven Redmond Repels mosquitoes and a variety of insects harmful to vegetable plants. 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. Rosemary's oils are as delicious to home cooks who use herbs as they are unpleasant to many insects. The plant itself and its cuttings are effective repellents. You can make a simple repellent spray by boiling one quart of dried rosemary in a quart of water for 20 to 30 minutes and then straining the liquid into a container at least a half-gallon in size that contains a quart of cool water. Put a cap on the combined liquid and store it in the refrigerator. Add the repellent to small squirt bottles as needed when going outdoors. Discard the remaining repellent in the refrigerator when it no longer has a strong telltale smell of rosemary. Sage Like rosemary, sage has a strong smell that's pleasant to us but not to insects. Ryan Yee/Shutterstock Like rosemary, sage is a perennial plant that can be grown in planters on a patio or planted into landscaped beds. If you're camping or making s'mores in the backyard, toss a little sage or rosemary into the fire. The scented smoke helps keep away unwanted insects. You can make a bug repellant spray using sage, too. Try this recipe from SFGate, which incorporates rosemary, mint and apple cider vinegar. Catnip Treehugger / Steven Redmond Though catnip is an herb, it's one that people usually don't eat. Cats love it, of course. A member of the mint family, it contains a chemical called nepetalactone, which attracts cats but repels insects such as mosquitoes, flies, deer ticks and cockroaches. Essential oils from catnip can be used to make a DIY natural insect repellent spray like this one. 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. Other herbs Bay leaves: Repel flies. When you grow this plant, you won't have to rely on the dried leaves from stores to add flavor to roasts and soups. Just pick the leaves as you need them.Chives: Repel carrot flies, Japanese beetle and aphids.Dill: Repels aphids, squash bugs, spider mites, cabbage loopers and tomato hornworms.Fennel: Repels aphids, slugs and snails.Lemon balm: Repels mosquitoes.Oregano: Repels many pests and will provide ground cover and humidity for peppers.Parsley: Repels asparagus beetles.Thyme: Repels whiteflies, cabbage loopers, cabbage maggots, corn earworms, whiteflies, tomato hornworms and small whites. Next up: Ornamental flowers Alliums Beautiful tall alliums will keep insects out of your vegetable garden. Toshihiro Gomo [CC BY 2.0]/Flickr Plants in the Allium family, such as the dramatic Allium giganteum which has flower heads that adorn stalks up to six feet tall, are regarded as a broad-spectrum natural insecticide. They repel numerous insects that plague vegetable gardens, including slugs, aphids, carrot flies and cabbage worms. Plants that will benefit from the proximity of alliums include tomatoes, peppers, potatoes, cabbage, broccoli, kohlrabi and carrots. They also will keep aphids off rose bushes. Alliums include small-growing herbs such as chives and garlic chives, leeks and shallots. Chrysanthemums Treehugger / Steven Redmond Repel roaches, ants, Japanese beetles, ticks, silverfish, lice, fleas, bedbugs, spider mites, harlequin bugs and root-knot nematodes. The ingredient in chrysanthemums that makes them so effective as an insect-repelling companion plant is pyrethrum. Because pyrethrins can kill flying and jumping insects, they are used in America's most commonly available home and garden insecticide and are frequently used in indoor sprays, pet shampoos and aerosol bombs. Although chrysanthemum flowers can be used to make an insecticidal spray, pyrethrum can be carcinogenic to humans and care should be taken in using them in this form. Make sure you understand the risks. Marigolds Aphids, mosquitoes and even rabbits don't like the smell of marigolds. Swaminathan [CC BY 2.0]/Flickr The scent from various types of marigolds repels aphids, mosquitoes and even rabbits. The roots of marigolds are well-known among farmers to repel nematodes , though those qualities require a year to take effect. They have even been proven to repel whiteflies away from tomato plants, according to a study published in 2019 in PLOS One by Newcastle University's School of Natural and Environmental Sciences. Researchers discovered that marigolds release limonene, which slows down whiteflies when they are flying around tomato plants. Grow marigolds as an annual in most parts of the country, mixed in along the border of your flower beds or interspersed throughout your vegetable garden as they can also spur on the growth of certain plants, especially roses. Although marigolds are easy to grow in sunny locations, they can fall victim to gray mold, several types of leaf spot, powdery mildew, damping off and root rot. Nasturtiums Nasturtiums release an airborne chemical that repels insects. Christian Guthier [CC BY 2.0]/Flickr Repel whiteflies, squash bugs, aphids, many beetles and cabbage loopers. Nasturtiums could be considered the poster child for companion planting, which is growing a variety of plants close to one another for the benefits each brings to the others. Nasturtiums release an airborne chemical that repels predacious insects, protecting not just the nasturtium but other plants in the grouping. Because many of the insects nasturtiums repel favor vegetables — tomatoes, cucumbers, kale, kohlrabi, collards, broccoli, cabbage and radishes — nasturtiums are an idea choice for planting along the edges of vegetable gardens. Fortunately, nasturtiums do not repel the all-important pollinator — the bumblebee. Petunias Treehugger / Steven Redmond Repel aphids, tomato hornworms, asparagus beetles, leafhoppers and squash bugs. Some people think of petunias as nature's pesticide. They're popular mostly because they are available in a variety of bright colors, require such minimal maintenance they are almost foolproof to grow and can be grown in garden beds, containers or hanging baskets. Plant them in sunny areas near vegetables and herbs such as beans, tomatoes, peppers and basil. Geraniums Pelargonium citrosum is also known as the Mosquito Repellent Plant. ajisai13/Shutterstock Geraniums can repel leafhoppers and other types of insects. One type of geranium, Pelargonium citrosum, is known as the Mosquito Repellent Plant. When in bloom, they have pretty flowers with a lemon-like fragrance that can help keep bugs at bay. These plants grow fast and like sunny, dry climates. Plant them in flower beds or vegetable gardens. Floss flowers Floss flowers produce a chemical called coumarin, which mosquitos don't like. Real Moment/Shutterstock Floss flowers contain coumarin , a chemical used in bug repellent sprays. Mosquitoes don't like the smell of the chemical, which is also found in sweetgrass. These small, flowering plants produce blue, pink and white blooms in the summer and fall. They work well in rock gardens, flower beds or as an edging plant. Floss flowers like really fertile soil, so you may want to fertilize them. Other ornamental flowers Common lantanas: Repel mosquitoes.Four o'clocks: Attract but poison Japanese beetle.Narcissus: Repel moles. Then the carnivorous plants Pitcher plants Pitcher plants trap and eat insects. Eric Sonstroem [CC BY 2.0]/Flickr Trap and ingest insects. Pitcher plants are the largest group of carnivorous plants. 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, the insect finds itself on a slippery surface with downward-facing hairs. The insect then either slips or falls into a pool of water. Once in the water, it drowns or dies of exhaustion in trying to escape, which is impossible because of the downward-facing hairs. The plant then digests the insect. Insects 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 area that stays moist, generally a difficult combination for home gardeners. Growing them in pots sitting in a saucer of water is easier. However, don't keep the growing medium too wet. It just needs to be moist. Others Venus flytrap: Consumes ants and other insects. View Article Sources Kynes, Sandra. Llewellyn's Complete Book of Essential Oils. Llewellyn, 2019. Auerbach, Paul S. Wilderness Medicine (6th Edition). Elsevier Science. 2011. 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 “15 Garden Plants That Repel Pests Naturally.” MasterClass. “Pest Control Companion Planning Chart.” Brigham Young University. Boyd, Carolyn. “Bait & Switch?.” Texas A&M Agrilife Extension. Hooks, Cerutti R.R., et al. “Using marigold (Tagetes spp.) as a cover crop to protect crops from plant-parasitic nematodes.” Applied Soil Ecol. 2010, vol. 46, pp. 307-320., doi:10.1016/j.apsoil.2010.09.005 Conboy Niall J.A., et al. “Companion planting with French marigolds protects tomato plants from glasshouse whiteflies through the emission of airborne limonene.” PLoS ONE. 2019, vol. 14, e0213071., doi:10.1371/journal.pone.0213071 Faires, Nicole. The Ultimate Guide to Natural Farming and Sustainable Living Permaculture for Beginners. Skyhorse Publishing. 2014. “Growing Plants for Hawaiian Lei.” College of Tropical Agriculture and Human Resources University of Hawaii at Manoa. Llorera, Daisyl Ann L., et al. “Lantana Camara Leaf Extract: A Prospective Organic Mosquito Larvicide,” CAM Research Journal, vol. 2, no. 1, September 2014, pp. 96-111. Anderson, Marcia. “Excavation Experts: Are Moles or Voles Ruining your Lawn? (Part 2).” Environmental Protection Agency. 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 “Venus flytrap.” U.S. Fish & Wildlife Service.