12 Plants That Repel Unwanted Insects (Including Mosquitoes)

Basil

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. It is pungent and effective even without needing to be crushed.

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.

Lavender

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.

Lemongrass

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.

Lemon Thyme

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, 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. You can also burn some sprigs on a barbecue or campfire to keep mosquitoes at bay temporarily.

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.

Mint

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

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. You can also toss some sprigs on the grill to scare off mosquitoes from the immediate vicinity.

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.

Catnip

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. In lab trials, nepetalactone has been found to be even more effective than DEET at repelling mosquitoes; however, when applied topically, it has little effect.

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.

Alliums

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, slugs, cabbage worms, 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

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 floral borders, and relying on their natural pyrethrum, you can receive the same insect-repelling advantage without the harmful effects.

Nasturtiums

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

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

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 sugary 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.

Keep in mind, though, that while your pet carnivorous plant might catch the occasional insect, it's not likely going to make a major dent in a mosquito or fly infestation at your home.