Flies are among the most ubiquitous and ecologically significant insects on earth, belonging to the order Diptera — meaning two wings — which encompasses over 125,000 known species distributed across virtually every habitat on every inhabited continent. While most people associate flies primarily with nuisance and disease transmission, they play genuinely important ecological roles as pollinators, decomposers, and food sources for countless other animal species. The common housefly alone is estimated to carry over 100 different pathogens on its body, making fly control a genuine public health concern in homes, food preparation areas, and livestock facilities worldwide.
Flies reproduce with extraordinary speed — a single female housefly can lay up to 500 eggs in her lifetime and the entire life cycle from egg to adult can be completed in as little as 7 to 10 days under warm conditions. Global economic losses attributable to fly damage in agriculture and livestock production run into billions of dollars annually, with the Australian sheep blowfly alone costing the Australian wool industry an estimated 280 million dollars per year. Different fly species are attracted to different environments and food sources, with some preferring decaying organic matter, others targeting fresh food and cooking odors, and still others seeking blood meals from humans and animals.
The use of aromatic plants to repel flies is one of the oldest and most widely practiced forms of natural pest management, with historical records from ancient Egyptian, Greek, Roman, and medieval European cultures all documenting the use of strongly scented herbs and plants to deter flies from living spaces, food stores, and stables. The mechanism of action is primarily olfactory — the volatile aromatic compounds produced by these plants overwhelm or confuse the fly’s highly sensitive olfactory receptors, making the protected area less attractive or actively repellent to approaching flies. Many of the most effective fly-repelling plants produce compounds that are simultaneously pleasant to humans while being intensely deterrent to flies.
Growing fly-repelling plants around the home, patio, garden, and livestock areas offers a natural, chemical-free, environmentally friendly alternative or complement to conventional fly control methods. Many of the most effective fly-repelling plants are also useful herbs, beautiful ornamental plants, or both — making them genuinely multi-functional additions to any garden. The most effective approach combines multiple fly-repelling plants in strategic locations — near doorways, windows, outdoor dining areas, compost bins, and livestock shelters — where their aromatic volatile compounds create overlapping zones of deterrence that significantly reduce fly pressure without any synthetic chemicals.
Plants that repel Flies
1. Lavender
Lavender is the most widely recommended and well-documented fly-repelling plant available to home gardeners, producing aromatic volatile compounds — particularly linalool and linalyl acetate — that are intensely deterrent to houseflies, blowflies, and numerous other fly species while being deeply pleasant to humans.
Planting lavender near doorways, windows, patios, and outdoor dining areas creates a naturally fragrant barrier that significantly reduces fly intrusion, and dried lavender bundles hung inside the home provide additional indoor fly deterrence. It grows to 18 to 30 inches in most garden varieties and is hardy in USDA zones 5 to 9.
2. Basil
Basil is one of the most effective and practical fly-repelling plants for the home garden and kitchen, producing powerful volatile aromatic compounds — particularly eugenol and linalool — that are strongly deterrent to houseflies and mosquitoes while simultaneously providing one of the most useful culinary herbs available.
Potted basil plants placed on kitchen windowsills, beside outdoor dining tables, and near doorways are widely reported to significantly reduce fly activity in their immediate vicinity. It grows to 12 to 24 inches as an annual herb in most climates and performs best in full sun with consistently moist soil.
3. Mint
Mint is one of the most potent and widely used natural fly repellents available, producing high concentrations of menthol and other volatile compounds that are intensely deterrent to houseflies, blowflies, horse flies, and stable flies across a wide range of species.
The strong, pervasive aroma of mint — particularly spearmint and peppermint varieties — overwhelms the olfactory receptors of flies and creates a deterrent zone that extends well beyond the immediate vicinity of the plant. It spreads vigorously and is best grown in containers to prevent it becoming invasive, reaching 12 to 24 inches in height and performing in USDA zones 3 to 9.
4. Rosemary
Rosemary is a highly effective, dual-purpose fly-repelling plant producing the volatile aromatic compound camphor alongside numerous other terpenoids that are strongly deterrent to flies and other flying insects while making it one of the most useful and beloved culinary herbs in the world.
The aromatic leaves and stems repel flies year-round as an evergreen shrub in mild climates, providing continuous protection near doorways, garden seating areas, and kitchen windows. It grows to 2 to 4 feet in height as a perennial shrub in USDA zones 7 to 10 and as an annual herb in colder zones.
5. Marigold
Marigolds are among the most widely planted and most effectively tested natural insect-repelling plants in horticulture, producing pyrethrum compounds and strongly aromatic volatile compounds from both the flowers and the foliage that repel flies, mosquitoes, aphids, and numerous other pest insects.
Planted in borders, containers, and window boxes near outdoor living areas and kitchen doors, they create an aromatic barrier that reduces fly activity across the surrounding area. French marigolds reaching 6 to 12 inches in height are particularly effective due to their very strong, pungent foliage aroma, while African marigolds reaching 24 to 36 inches provide additional deterrence through sheer aromatic mass.
6. Catnip
Catnip is one of the most scientifically well-documented natural insect repellents available, with research by Iowa State University demonstrating that nepetalactone — the primary volatile compound in catnip — is approximately ten times more effective at repelling certain fly and mosquito species than DEET, the most widely used synthetic insect repellent.
It grows to 18 to 36 inches as a vigorous, spreading perennial herb, hardy in USDA zones 3 to 9, and the crushed or bruised leaves release the deterrent compounds most effectively. It is an outstanding fly-repelling plant for garden borders, though its effect on neighborhood cats should be considered.
7. Bay Laurel
Bay Laurel is a classic, traditional fly-repelling plant used since ancient Greek and Roman times to deter flies from food stores, kitchens, and living spaces, producing the aromatic volatile compound eucalyptol and other terpenoids that are strongly deterrent to flies and food moths alike.
Fresh or dried bay leaves placed near food storage areas, on kitchen shelves, and around waste bins are a traditional and still widely practiced fly deterrent, and potted bay trees placed near doorways and patios provide ongoing deterrence from the aromatic leaves. It grows to 4 to 20 feet depending on conditions and is hardy in USDA zones 8 to 10.
8. Lemon Balm
Lemon Balm is a highly effective fly-repelling herb producing very high concentrations of citronellal and other lemony volatile compounds that are strongly deterrent to flies, mosquitoes, and gnats while providing a gentle, pleasant lemon fragrance that is universally appealing to humans.
Crushing or bruising the leaves releases the highest concentrations of the deterrent compounds, and rubbing crushed lemon balm leaves directly on exposed skin provides temporary personal fly protection. It grows to 18 to 24 inches as a spreading perennial herb, hardy in USDA zones 3 to 7, and self-seeds readily in garden conditions.
9. Pennyroyal
Pennyroyal is one of the most potently fly-repelling members of the mint family, producing exceptionally high concentrations of pulegone — one of the most effective natural insect-deterrent compounds known — that repels flies, fleas, mosquitoes, and numerous other pest insects with remarkable effectiveness.
It has been used as a natural fly repellent in homes, stables, and food storage areas across Europe and North America for centuries, with dried pennyroyal bundles hung in doorways and windows a traditional household fly deterrent. It grows to 6 to 12 inches as a low, spreading perennial and is hardy in USDA zones 5 to 9. Note that pennyroyal is toxic if ingested and should be kept away from children and pets.
10. Tansy
Tansy is a traditional cottage garden herb with a very long history of use as a fly repellent in European households, producing high concentrations of thujone and camphor volatile compounds that are strongly deterrent to flies, mosquitoes, and ants. Bunches of tansy were traditionally hung in doorways and windows and strewn on floors of homes and stables to deter flies throughout the summer months, a practice documented across medieval and early modern European sources.
It grows to 3 to 4 feet as a vigorous, spreading perennial, hardy in USDA zones 4 to 8, and produces attractive, button-like yellow flowers in summer. Note that tansy contains toxic compounds and should not be used in food preparation.
11. Wormwood
Wormwood is one of the most powerfully aromatic of all fly-repelling plants, producing very high concentrations of thujone, absinthin, and other bitter, pungent volatile compounds that are strongly deterrent to flies, moths, and numerous other pest insects across a wide range of species.
The extraordinarily bitter, intense aroma of the silver-grey foliage is effective even at relatively low plant densities and the silvery leaf color provides significant ornamental value in addition to the deterrent properties. It grows to 3 to 4 feet as a vigorous, spreading perennial, hardy in USDA zones 4 to 9, and requires minimal care once established.
12. Rue
Rue is an ancient, traditional fly-repelling herb used since at least ancient Greek times to deter flies and other insects from homes and food preparation areas, producing powerful volatile compounds including 2-undecanone that are strongly deterrent to flies, fleas, beetles, and mosquitoes.
The blue-grey, aromatic foliage releases deterrent compounds continuously in warm weather and the plant provides year-round ornamental value as an evergreen sub-shrub in mild climates. It grows to 18 to 24 inches, is hardy in USDA zones 4 to 9, and produces attractive yellow flowers in summer. Note that rue can cause skin irritation in sensitive individuals and should be handled with care.
13. Eucalyptus
Eucalyptus is one of the most widely used and scientifically documented natural fly repellents available, producing very high concentrations of eucalyptol — also called cineole — alongside numerous other volatile terpenoid compounds that are strongly deterrent to flies, mosquitoes, and numerous other biting and nuisance insects.
Eucalyptus essential oil is one of the most commercially important natural insect repellent ingredients used in the personal care and pest control industry, and growing eucalyptus trees near outdoor living areas provides substantial, ongoing fly deterrence from the continuously released aromatic volatile compounds. Most species reach considerable size outdoors in USDA zones 8 to 11.
14. Citronella Grass
Citronella Grass is the primary commercial source of citronella essential oil — the most widely used natural insect repellent in the world, found in candles, sprays, lotions, and diffusers across every market globally — producing extraordinarily high concentrations of citronellal, geraniol, and citronellol that are among the most effective natural fly and mosquito deterrents known.
Growing citronella grass plants in large containers on patios and around outdoor seating areas provides significant ambient fly deterrence from the continuously released aromatic compounds. It grows to 4 to 6 feet in height as a tropical grass suited to USDA zones 9 to 12 or grown as an annual container plant in cooler climates.
15. Lemon Thyme
Lemon Thyme is a highly effective fly-repelling herb combining the general insect-deterrent properties of standard thyme with additional citrusy, lemony volatile compounds that are particularly effective against houseflies and fruit flies.
The aromatic foliage releases deterrent compounds continuously in warm weather and the crushed leaves provide strong personal fly deterrence when rubbed on exposed skin. It grows to 6 to 12 inches as a low, spreading, evergreen perennial sub-shrub, hardy in USDA zones 5 to 9, and produces attractive pale pink to white flowers in summer that are excellent for bees and other pollinators.
16. Thyme
Thyme produces thymol and carvacrol — two of the most effective natural insect-deterrent volatile compounds identified in plant species — that repel flies, mosquitoes, and numerous other pest insects with documented effectiveness in laboratory and field studies.
The strongly aromatic foliage releases deterrent compounds throughout the growing season and the plant is among the most multi-functional of all fly-repelling plants, simultaneously providing an outstanding culinary herb, attractive garden perennial, and excellent pollinator plant. It grows to 6 to 12 inches, is hardy in USDA zones 4 to 9, and requires minimal care in well-draining, sunny positions.
17. Sage
Sage produces camphor, thujone, and numerous other strongly aromatic volatile compounds that are effectively deterrent to flies, mosquitoes, and other flying insects when the plant is growing actively and releasing its characteristic, powerful aroma. Burning dried sage — smudging — creates an even more concentrated aromatic smoke that has been used by numerous indigenous cultures worldwide as a fly and insect deterrent in enclosed spaces.
It grows to 18 to 24 inches as a compact, evergreen perennial, hardy in USDA zones 4 to 8, and is one of the most attractive and versatile fly-repelling herbs for the combined kitchen and ornamental garden.
18. Lemon Verbena
Lemon Verbena is an intensely lemon-fragrant shrubby herb producing very high concentrations of citral, limonene, and other citrusy volatile compounds that are effectively deterrent to flies, mosquitoes, and gnats while providing one of the most intensely pleasant lemon fragrances of any garden plant.
The fresh leaves rubbed on exposed skin provide reasonable temporary personal fly protection and the plant growing in pots near outdoor seating areas provides ambient deterrence from the continuously released aromatic compounds. It grows to 2 to 4 feet in USDA zones 8 to 10 or as a tender perennial container plant in cooler climates.
19. Witch Hazel
Witch Hazel produces astringent, aromatic compounds including hamamelis tannins and volatile aromatic alcohols that have modest fly-deterrent properties alongside their much more widely documented medicinal and cosmetic applications.
The aromatic bark and leaves have been used in traditional North American folk medicine as an insect deterrent and the plant provides significant additional garden value through its extraordinary winter-blooming, fragrant flowers that appear on bare stems from autumn through early spring. It grows to 6 to 15 feet as a large, multi-stemmed deciduous shrub, hardy in USDA zones 3 to 8.
20. Lemongrass
Lemongrass is a tall, tropical grass producing very high concentrations of citral — the primary volatile compound responsible for its intensely lemon-like fragrance — alongside citronellal, geraniol, and other volatile terpenoids that are effectively deterrent to flies, mosquitoes, and gnats.
It is closely related to citronella grass and shares many of its insect-deterrent properties, and the fresh stalks placed near food preparation areas and outdoor dining tables provide significant ambient fly deterrence. It grows to 3 to 5 feet as a tropical clumping grass suited to USDA zones 9 to 11 or grown as an annual or container plant in cooler climates.
21. Peppermint
Peppermint is one of the most effective and most widely recommended natural fly repellents among the mint family, producing exceptionally high concentrations of menthol and menthone that are among the most potent natural fly-deterrent volatile compounds available from garden plants.
Research has demonstrated that peppermint oil is effective against houseflies, blowflies, stable flies, and numerous other fly species, and the living plant releases sufficient concentrations of these compounds to provide meaningful ambient deterrence in its immediate vicinity. It grows to 12 to 18 inches as a vigorously spreading perennial, hardy in USDA zones 3 to 8, and is best grown in containers to control its spreading habit.
22. Spearmint
Spearmint produces carvone and limonene — volatile compounds that are effectively deterrent to flies and mosquitoes — alongside the general menthol compounds shared with peppermint, making it an effective fly-repelling plant with a somewhat gentler, more refreshing fragrance than peppermint.
It is particularly effective against fruit flies when placed near fruit bowls, compost bins, and kitchen waste areas where fruit fly pressure is highest. It grows to 12 to 24 inches as a spreading perennial, hardy in USDA zones 3 to 9, and is similarly best grown in containers to prevent it from spreading uncontrollably through garden beds.
23. Chrysanthemum
Chrysanthemums are among the most scientifically important fly-repelling plants in the world, producing pyrethrin compounds — the most widely used natural insecticide in organic and conventional pest control products globally — that are toxic to flies and numerous other pest insects at sufficient concentrations.
The natural pyrethrin content in chrysanthemum flowers has been extracted and refined into pyrethrum powder and pyrethrin spray products that account for a significant global natural insecticide market. Growing chrysanthemums near outdoor areas and garden borders provides ambient fly deterrence from the ongoing release of pyrethrin volatiles. They grow to 18 to 36 inches and are hardy in USDA zones 5 to 9.
24. Feverfew
Feverfew is a traditional cottage garden herb producing pyrethrins and other volatile aromatic compounds that are effectively deterrent to flies, mosquitoes, and other flying insects, with a long history of use as a natural insect repellent in European folk medicine and household practice.
The strongly aromatic foliage releases deterrent compounds continuously throughout the growing season and the attractive, white daisy-like flowers provide significant ornamental value in addition to the deterrent properties. It grows to 18 to 24 inches as a short-lived perennial or annual, hardy in USDA zones 5 to 9, and self-seeds readily.
25. Clove
Clove plants and clove-based preparations are among the most potent natural fly repellents available, producing eugenol — one of the most effective natural insect-deterrent compounds identified in research — in very high concentrations in both the flowers and the leaves.
Whole dried cloves placed near food storage areas, in fruit bowls, and around waste bins are a traditional and highly effective fly deterrent used across European and Asian household traditions, and the growing plant provides ongoing deterrence from eugenol volatiles released by the aromatic foliage. It grows to 20 to 30 feet as a tropical tree suited to USDA zones 10 to 12.
26. Calamint
Calamint is a charming, underused aromatic perennial herb closely related to mint and producing similar volatile menthol-type compounds that are effectively deterrent to flies, gnats, and mosquitoes while providing an attractive, compact garden plant with clouds of small, pale pink to lavender flowers beloved by bees throughout summer.
The crushed or bruised leaves release the deterrent compounds most powerfully and the plant growing in borders near outdoor seating provides ambient fly deterrence from the continuously released aromatics. It grows to 12 to 18 inches as a compact perennial, hardy in USDA zones 5 to 9.
27. Lemon Eucalyptus
Lemon Eucalyptus is a specific eucalyptus variety that produces exceptionally high concentrations of citronellal — the primary deterrent compound in commercial citronella products — and has been the subject of significant research into natural insect repellent compounds, with the Centers for Disease Control and Prevention in the United States recognizing oil of lemon eucalyptus as an effective insect repellent.
Growing lemon eucalyptus plants near outdoor living areas provides significant fly and mosquito deterrence and the oil extracted from the leaves is one of the most effective natural insect repellent ingredients commercially available. It grows to 20 to 40 feet in USDA zones 8 to 11.
28. Geranium (Scented)
Scented geraniums — particularly the citronella, lemon, and rose-scented varieties — are among the most popular and widely recommended natural fly and mosquito repelling container plants for patios, balconies, and outdoor dining areas, producing volatile aromatic compounds including citronellol and geraniol that are effectively deterrent to flies and mosquitoes at close range.
The citronella-scented geranium in particular is widely marketed as a natural mosquito and fly repellent plant and is one of the most commonly sold insect-repellent plants in mainstream garden retail. Most scented geraniums grow to 18 to 36 inches and are tender perennials suited to USDA zones 9 to 11 or grown as annual container plants.
29. Oregano
Oregano produces carvacrol and thymol — the same potent volatile insect-deterrent compounds found in thyme — in very high concentrations particularly in the strongly aromatic Mediterranean varieties, making it an effective fly-deterrent herb for the kitchen garden and outdoor dining area.
The strongly aromatic foliage provides continuous ambient fly deterrence near outdoor food preparation and dining areas where housefly and fruit fly pressure is typically highest, while simultaneously providing one of the most important and versatile culinary herbs for Mediterranean cooking. It grows to 12 to 18 inches as a spreading perennial, hardy in USDA zones 4 to 10.
30. Lemon Mint
Lemon Mint is a strongly lemon-fragrant mint variety producing high concentrations of limonene, linalool, and citrusy volatile compounds that are effectively deterrent to flies and mosquitoes with a particularly pleasant, refreshing lemon-mint fragrance.
The combination of mint-type insect deterrence and citrus volatile compounds makes it particularly effective against a wide range of fly species, and the crushed leaves provide strong personal protection when rubbed on exposed skin. It grows to 18 to 24 inches as a spreading perennial, hardy in USDA zones 5 to 9, and is best grown in containers to control spreading.
31. Camphor Plant
The Camphor Plant produces extremely high concentrations of camphor — one of the most potent and widely used natural insect-deterrent volatile compounds — in the leaves, stems, and bark, creating a powerfully aromatic environment that is strongly deterrent to flies, moths, and numerous other insect pests.
Camphor has been used as a natural insect repellent in Asia and Europe for centuries and remains a commercially important natural insect-deterrent compound in mothballs, chest linings, and household insect repellent products. It grows to 50 to 100 feet as a large tree in USDA zones 8 to 11 but can be maintained as a smaller specimen through regular pruning.
32. Nepeta (Catmint)
Catmint, the ornamental garden cousin of catnip, produces nepetalactone and similar volatile compounds that are effectively deterrent to flies, mosquitoes, and aphids while providing one of the most attractive and long-blooming ornamental perennials available for garden use.
The lavender-blue flower spikes produced in abundance from early summer through autumn are outstanding for bees and pollinators while simultaneously deterring fly pests, making catmint one of the most wildlife-beneficial fly-repelling plants available. It grows to 18 to 36 inches as a compact, spreading perennial, hardy in USDA zones 4 to 8.
33. Pyrethrum Daisy
The Pyrethrum Daisy is the most important commercial source of natural pyrethrin insecticide in the world, growing on an enormous commercial scale in Kenya — which produces approximately 70 percent of the world’s natural pyrethrum — and producing flower heads with pyrethrins content sufficient to provide very significant fly deterrence in the immediate garden environment.
It produces attractive, white to pale pink daisy flowers through summer and the dried, powdered flower heads have been used as an effective natural insecticide for over 2,000 years. It grows to 18 to 24 inches as a perennial, hardy in USDA zones 5 to 9.
34. Pennyroyal Mint
Pennyroyal Mint is the specific American native cousin of European pennyroyal, producing high concentrations of pulegone and other volatile mint-family compounds that are effectively deterrent to flies, fleas, and mosquitoes across a wide range of species.
It was widely used by Native American peoples as a natural insect repellent applied to clothing and skin, and colonial American households used it as a fly-deterrent strewing herb on floors and near doorways. It grows to 6 to 12 inches as a low, creeping perennial, hardy in USDA zones 5 to 9, and spreads readily in moist conditions.
35. Sweet Cicely
Sweet Cicely is a fragrant woodland herb producing anise-scented volatile compounds including anethole and estragole that are modestly deterrent to flies and other flying insects while providing an attractive, large-leafed, architectural garden plant with finely divided, fern-like foliage and clusters of small white flowers in spring.
The strongly anise-scented leaves and seeds have been used in traditional European folk medicine as a mild natural insect deterrent and the plant provides significant additional garden value as a shade-tolerant ornamental and edible herb. It grows to 3 to 5 feet, hardy in USDA zones 3 to 7.
36. Hyssop
Hyssop is a traditional Mediterranean aromatic herb producing pinocamphone and isopinocamphone volatile compounds that are effectively deterrent to flies, cabbage white butterflies, and other pest insects while providing an attractive, compact garden plant with vivid, deep blue-purple flower spikes that are exceptionally attractive to bees and other pollinators.
It has been grown in monastery herb gardens across Europe for centuries as both a medicinal herb and a fly-deterrent plant near food storage areas. It grows to 18 to 24 inches as a compact, semi-evergreen perennial, hardy in USDA zones 3 to 9.
37. Lemon Catnip
Lemon Catnip is a lemon-scented variety of catnip producing a combination of the potent nepetalactone compounds of standard catnip with additional citrusy lemon volatile compounds, creating a particularly broad-spectrum natural fly and mosquito deterrent with a more pleasant, less cat-attracting fragrance than standard catnip.
The combination of the well-documented insect-deterrent properties of nepetalactone with the additional citrus deterrence makes it an effective and pleasant-smelling natural fly-repelling plant for garden borders and container planting. It grows to 18 to 30 inches as a spreading perennial, hardy in USDA zones 3 to 9.
38. Sweet Basil
Sweet Basil is the most commonly grown basil variety and the most practically useful fly-repelling basil for kitchen and home use, producing the highest concentrations of eugenol, linalool, and estragole of the commonly available basil types — compounds that are effectively deterrent to houseflies and fruit flies in the immediate vicinity of the plant.
Potted sweet basil on the kitchen windowsill is among the most widely recommended and practically effective natural fly control measures for the kitchen, simultaneously deterring flies and providing fresh herb leaves for cooking throughout the summer season. It grows to 12 to 24 inches as an annual herb.
39. Apple Mint
Apple Mint produces the characteristic menthol-type volatile compounds of the mint family with an additional sweet, apple-like fragrance note that makes it particularly pleasant as a fly-repelling plant near outdoor dining and relaxation areas.
The soft, broadly rounded, fuzzy leaves release the deterrent compounds most powerfully when brushed or crushed and the plant creates significant ambient fly deterrence in its immediate vicinity. It grows to 18 to 30 inches as a spreading perennial, hardy in USDA zones 4 to 9, and like all mints is best grown in containers to prevent garden spreading.
40. Vetiver
Vetiver is a tropical clumping grass producing high concentrations of vetivone, khusimol, and numerous other complex sesquiterpene volatile compounds with documented insect-deterrent properties that have been used in traditional Indian, Sri Lankan, and Southeast Asian household pest control practices for centuries.
The strongly aromatic roots are the primary source of the deterrent compounds and have been woven into screens, mats, and sachets as natural insect repellents across South Asia for generations. It grows to 3 to 5 feet as a clumping tropical grass in USDA zones 9 to 11 and is increasingly available from specialist herb and aromatic plant nurseries.
41. Southernwood
Southernwood is a traditional cottage garden aromatic shrub producing very high concentrations of absinthol and other bitter, intensely aromatic volatile compounds that are strongly deterrent to flies, moths, and other flying insects with a very long history of use as a natural insect repellent across European folk traditions.
Bunches of southernwood were traditionally hung in wardrobes and linen cupboards to deter moths and near doorways and windows to repel flies, and the plant was a staple of medieval monastery herb gardens for exactly this purpose. It grows to 3 to 4 feet as a vigorous, semi-evergreen shrub, hardy in USDA zones 4 to 8.
42. Lemon Basil
Lemon Basil combines the general fly-deterrent volatile compounds of standard basil with additional citrusy lemon volatile compounds — particularly limonene and citral — that broaden the spectrum of fly species deterred and intensify the overall deterrent effect beyond that of standard sweet basil alone.
The lemon-basil fragrance is particularly pleasant and effective near outdoor food preparation and dining areas where the combination of basil and lemon aromatics creates a strongly deterrent microenvironment. It grows to 12 to 20 inches as an annual herb in most climates and performs best in full sun with consistent moisture.
43. Santolina (Cotton Lavender)
Santolina, commonly called Cotton Lavender despite not being a true lavender, is a compact, silver-leafed Mediterranean aromatic shrub producing strongly pungent, bitter volatile compounds including camphor and other terpenoids that are effectively deterrent to flies, moths, and beetles with a very long history of use as a natural insect repellent in European cottage and knot garden traditions.
The intensely aromatic silver foliage provides continuous ambient fly deterrence throughout the growing season and the compact, dome-shaped habit provides significant year-round ornamental value in the garden. It grows to 18 to 24 inches, hardy in USDA zones 6 to 9.
44. Allium (Ornamental Onion)
Ornamental alliums produce the sulfur-containing volatile compounds characteristic of the onion and garlic family — particularly allicin and related compounds — that are effectively deterrent to flies, aphids, and other pest insects in the immediate garden environment.
The large, spherical, purple or white flower heads of ornamental alliums are spectacular in the late spring and early summer garden while the sulfurous volatile compounds released by the bulbs and foliage create a deterrent zone around the plant. They grow to 12 to 48 inches depending on the variety and are hardy in USDA zones 4 to 8.
45. Garlic
Garlic is one of the most powerfully insect-deterrent plants available in the herb garden, producing exceptionally high concentrations of allicin and diallyl disulfide — sulfur-containing volatile compounds that are strongly deterrent to flies, aphids, spider mites, and numerous other pest insects at sufficient concentrations.
Garlic planted around the kitchen garden, near compost bins, and alongside vulnerable crops provides significant ambient fly deterrence and garlic spray preparations are among the most widely used natural pesticides in organic horticulture globally. Individual garlic bulbs are planted in autumn, maturing by early summer to 12 to 24 inches in height across USDA zones 3 to 9.
46. Lemon Geranium
Lemon Geranium is a strongly lemon-scented variety of scented geranium producing very high concentrations of citronellol, geraniol, and limonene — the primary volatile compounds responsible for the insect-deterrent properties of commercial citronella products — making it one of the most effectively fly and mosquito deterrent scented geranium varieties available.
The intensely lemon-fragrant leaves provide the highest concentration of deterrent compounds when bruised or crushed, and the plant growing near outdoor seating areas provides continuous ambient deterrence from the volatiles released by the aromatic foliage. It grows to 18 to 30 inches as a tender perennial suited to USDA zones 9 to 11.
47. Pineapple Sage
Pineapple Sage is a strongly aromatic sage variety producing a uniquely sweet, intensely fruity, pineapple-like fragrance from the aromatic foliage alongside the general sage-type camphor and terpenoid compounds that provide effective fly deterrence in the immediate vicinity of the plant.
The combination of attractive scarlet-red flowers — particularly appealing to hummingbirds — and the fly-deterrent aromatic foliage makes it one of the most multi-functional fly-repelling plants for the ornamental kitchen garden. It grows to 3 to 4 feet as a tender perennial in USDA zones 8 to 11 and as an annual herb in cooler climates.
48. Thai Basil
Thai Basil produces high concentrations of estragole, eugenol, and linalool — effective fly-deterrent volatile compounds — with a distinctively different, slightly spicier, more anise-like fragrance character than standard sweet basil that may be particularly effective against certain fly species attracted to the specific aromatic profile of sweet basil.
Placing potted Thai basil near outdoor Asian-cuisine cooking areas, street food stalls, and outdoor markets — where fly pressure around food is particularly intense — has been a traditional and widely practiced natural fly deterrent across Southeast Asian food culture for generations. It grows to 12 to 18 inches as an annual herb.
49. Mugwort
Mugwort is a traditional, widely distributed aromatic herb producing thujone, camphor, and numerous other intensely aromatic volatile compounds that are strongly deterrent to flies, mosquitoes, and moths with a very long history of use as a natural insect repellent across European, Asian, and Native American folk traditions.
Bunches of dried mugwort have been hung in doorways, stables, and food storage areas to deter flies across multiple cultural traditions worldwide, and the plant was used as a strewing herb in medieval European households specifically for fly deterrence. It grows to 3 to 5 feet as a vigorous, spreading perennial, hardy in USDA zones 3 to 8.
50. Clary Sage
Clary Sage is a large, beautiful biennial or short-lived perennial herb producing high concentrations of linalool, linalyl acetate, and sclareol — volatile aromatic compounds that are effectively deterrent to flies and other flying insects while making clary sage one of the most commercially important essential oil crops in the perfumery and aromatherapy industries.
The large, dramatic, purple-bracted flower spikes reaching 3 to 5 feet in height are highly ornamental and the strongly aromatic foliage provides continuous ambient fly deterrence throughout the growing season. It is hardy in USDA zones 4 to 9 and self-seeds readily in appropriate conditions.