There are several key mosquito repelling herbs, plants and flowers that are easy-to-grow, natural garden plants that help to keep outdoor rooms, decks and patios clear of pesky insect pests, yet are safe for honeybees, butterflies and pollinators. You may wish to explore substituting fragrant and strong-smelling herbs for commercial chemical sprays.
10 Key Mosquito Repelling Herbs to Grow at Home
1. Lemongrass or Citronella Grass
Citronella (Cymbopogon nardus and C. winterianusis) is the real deal. Citronella is the most common natural ingredient used in mosquito repellents and its strong citronella/lemon/citrus aroma covers other smells that attract mosquitoes (such as carbon dioxide from exhaling, or lactic acid from sweating), making it harder for them to find you. Citronella is offered commercially in many forms including scented candles and torches, but fresh leaves have the strongest smell. Citronella is in the same genus as Lemongrass (Citronella citrates), and the tender white bases of the grass are used in Thai cuisine, while the long slender leaves can be woven into a fan or mat. GardenGeri talks about Lemongrass on about.com: https://www.youtube.com/watch?v=DDwAuJGZAIk
Citronella nardus is a tropical, perennial ‘clumping’ grass that grows about 3-4 feet in metro-Atlanta and does best in full sun. Like any grass, springtime applications of nitrogen-rich compost or blood meal will increase vigor. It turns a lovely rust color in the autumn that harmonizes with fall mums and asters. Citronella sometimes winters over in Zone 8 or warmer, or if container-grown can be brought indoors during cold spells.
Get your citronella from a reliable source and choose Cybopogon nardus or Citronella winterianus. Other plants may be sold as ‘citronella scented’, but these do not have the mosquito repelling qualities of true citronella.
2. Lemon Thyme
Lemon Thyme has a greater concentration of citronella than the Scented Geranium widely sold as “fake citronella” or a mosquito repellent (!). Crushed leaves of thyme provide 62% of the repellency provided by chemical DEET.
Lemon Thyme is a hardy, edible perennial whose tiny blooms attract butterflies and bees in season. Its spreading, creeping habit is good on pathways or trailing down the side of a container or large pot.
3. Basil
All of the pungent kinds of Basil have a strong aroma even without touching or crushing. Pots of basil placed around the patio or deck are beautiful AND will help to keep mosquitoes away. Lemon Basil, Peruvian Basil, African Blue Basil and Cinnamon Basil are particularly strongly scented for this use. Basil Pesto is delicious on pasta, burgers, chicken, fish, veggies, tomatoes and just about anything grilled.
4. Ageratum
Also known as blue Floss Flower, annual Ageratum is a low-growing ornamental plant which reaches heights of 8 – 18” and is easily recognized by its lavender-blue flowers. This plant will thrive in full or partial sun and does not require rich soil. Taller Wild Ageratum blooms in late summer or fall.
Ageratum secretes coumarin, a smell that repels mosquitoes and an ingredient widely used in commercial mosquito repellents. Crush the leaves of Ageratum to increase the emitted odor, but don’t rub on the skin.
5. Catnip
Catnip is a natural mosquito repellent. Work at Iowa State in August 2001 found that catnip oil is ten times more effective than DEET, while in more recent work ISU has patented nepetalactone, the primary ingredient in catnip oil, in the search for a product to thwart mosquitoes.
Nepeta cateria, is very easy to grow. This low-growing, lavender-flowered perennial herb is related to mint, and grows easily as a cultivated perennial.
While catnip will repel mosquitoes in close proximity to the plant, some people apply crushed catnip leaves or catnip oil to a scarf or handkerchief for more robust protection. Or put 2 handfuls of catnip in the food processor, then add boiling water and white vinegar, and steep as a tea to brew a home-made mosquito repellent.
6. Lavender
One of the most beloved garden herbs, Lavender is “ever gray” and adds a silvery note to the landscape year-round. In bloom the lovely lavender-colored flowers are fragrant, and remain so even when dried. Lavender is a familiar fragrance for soaps and perfumes, but it can also repel mosquitoes. Try rubbing the crushed leaves or a few drops of lavender oil on a hankie or towel draped over your chair to repel pesky mosquitoes.
Give Lavender full sun, excellent drainage and an alkaline soil for best growth. In Atlanta this means the addition of coarse sand or Permatill to Georgia red clay along with plenty of organic matter. A flowerpot full of pulverized dolomite lime mixed in with the soil offsets the acidity of the native soils.
7. Marigolds
Ubiquitous yellow- and orange-flowered annuals, marigolds are tough annuals for flower borders with a distinctive smell that mosquitoes (and some people) find offensive. A member of the Daisy Family, Marigolds contain Pyrethrum, a natural pest control compound used in many organic insect repellents.
Marigolds do best with full sunlight and ertile soil. School kids often start marigolds for Mother’s Day from seed, but starter plants are inexpensive and readily available at garden centers. Sometimes marigolds will reseed in favorable conditions. Deadhead spent flowers to promote additional blooms.
Marigolds grown in containers can be positioned at entrances, open screened windows, decks or patios, and the smell may stop mosquitoes from going past this barrier. (Since wasps are attracted to bright yellow, avoid putting marigolds on the table.)
In addition to repelling mosquitoes, marigolds are said to be a companion plant for tomato plants (although this may be hearsay), so a few planted in and around tomatoes may help, and looks nice regardless.
Additional Strong-Smelling Members of the Marigold or Daisy Family (Asteraceae)
Santolina, Wormwood and the genus Tanacetum (tansy, pyrethrum, feverfew), all offer some repellent qualities and are easy to grow garden plants.
8. Lemon Balm
Really E-A-S-Y to grow, Lemon Balm smells like Citronella and is an edible herb in the Mint Family that grows in sun or shade. Rub the crushed or minced leaves on legs and arms or on a cloth worn around exposed limbs to repel mosquitoes.
When your lemon balm grows exuberantly, make Lemon Balm Wine Cooler for a cool and refreshing summer drink.
9. Pennyroyal
Fresh Pennyroyal is an amazingly effective natural mosquito repellent. This low-growing herb can be planted beneath a bench where shoes will bruise the leaves and emit the fresh minty smell, or in a vase as a cut flower for the table. Pennyroyal is also great against fleas and ticks. However, do not rub crushed Pennyroyal directly on your skin or on your dog’s coat because it is extremely toxic to the liver of humans, dogs and cats.
10. Bee Balm
Also known as Oswego Tea, Horsemint or Monarda, Bee Balm is perennial plant in the Mint family gives off a strong incense-like odor, confusing mosquitoes by masking the smell of its usual hosts (warm people).
Bee Balm is a fast growing, shade-tolerant and drought-resistant plant that reaches a height and width of 2 – 3 feet with pink, red, rose, white or lavender flower heads that attract pollinators such as bees, butterflies and hummingbirds to the garden. Bee balm grows in sun or shade and can be divided in spring or fall and given to friends or transplanted to other locations in the garden. Bee Balm leaves are also dried and used to make herbal tea.
Claims for Scented-Geranium “Citronella” are greatly exaggerated!
Garden centers often sell scented-geranium plants in place of citronella grass. These tender perennials (Pelargonium) are offered in pots ready to transplant to a larger container or in-ground beds. However, the University of Georgia cautions that no scientific data backs up the insect-repellent claims, with only 0.09% of the effective oil in contained in the leaves. Dr. Arthur Tucker of Delaware State College says that repellent claims are greatly exaggerated with only 0.09% of the effective oil in contained in the leaves.
Even without a repellent function, scented-geraniiums are wonderful, fragrant plants and are great houseplants or will occasionally winter-over in metro-Atlanta if temperatures do not fall below about 20 degrees F. Once established, new plants are easily propagated by cuttings and shared with friends and family after rooting. In addition to the “citronella-scented or lemon-scented geranium, there are many fun types of scented geraniums, from Rose to Coconut to Mint to Lime and more!
Additional Strategies
During summer and fall, folks are looking for ways to control mosquitoes. The first preventative measure is to drain standing water in order to eliminate breeding areas for mosquitoes. Mosquito dunks or mosquito fish are good to add to water gardens. Screen mosquitoes out of the house, and outside on the deck or patio, sit in front of a fan to blow lightweight mosquitoes away. A fabric softener sheet tucked into the sleeve also helps repel mosquitoes. Tea Tree or Neem is non-toxic and is effective as a repellent.
In addition to the discomfort of the itch, diseases such as Zika and the West Nile virus add to the problem. Commercial sprays are available, but exercise caution when using those containing DEET; adverse medical side effects can occur if used on children. Do not spray directly on the skin, but into a handkerchief or on a scarf, and wash off DEET repellents once you go back inside. Other DEET-free sprays are based on citrus oils or other non-toxic ingredients.
Digging Deeper