Using plants to deter insects is a natural control method relying on aromatic compounds to create an unwelcome environment. Effective nuisance control requires understanding the differences between the insects you wish to discourage. Bees are primary pollinators motivated by the search for nectar and pollen, while wasps are scavengers drawn to protein and sugary human food sources. Planting specific aromatic varieties acts as a gentle deterrent by masking attractive scents or confusing insect navigation.
Plants That Specifically Deter Wasps
Wasps, including yellow jackets and hornets, rely heavily on scent to locate food, ranging from sugary drinks to meat scraps. Plants producing strong, pungent odors are highly effective because they overload the wasps’ olfactory sensors, masking attractive food smells. This defense mechanism involves releasing volatile organic compounds (VOCs) that interfere with the insects’ ability to navigate toward a target.
Mint varieties are widely used deterrents, with species like peppermint and spearmint containing high concentrations of menthol and menthone. Pennyroyal, a type of mint, is particularly potent, emitting a powerful, sharp aroma that wasps find disagreeable. These robust herbs constantly release their repellent scent, making them ideal for container planting near outdoor dining areas.
Other powerful aromatic herbs like basil, thyme, and rosemary also serve as effective natural barriers. Basil contains compounds such as estragole and linalool, giving it a strong fragrance that masks the scent of nearby attractants. Thyme and rosemary possess oils that create a dense, herbaceous odor cloud wasps generally avoid.
Citronella grass (Cymbopogon nardus) and eucalyptus are known for distinct, sharp scents often utilized in commercial insect repellents. Citronella’s lemon-like scent contains citronellal, which deters various flying insects, including wasps. Similarly, the strong, camphoraceous aroma from eucalyptus leaves, rich in cineole, creates a localized zone of repulsion.
Plants That Specifically Deter Bees
Deterring bees requires a different approach, as these insects seek floral rewards, not human food. The most effective plants either emit strong, non-floral scents that confuse the bee’s navigation system or have flower structures offering little accessible pollen or nectar. Since bees are beneficial pollinators, the goal is to redirect them from specific areas, not eliminate them entirely.
French marigolds (Tagetes patula) are included in this category because their leaves and flowers release a strong, musky odor many insects find objectionable. This pungent scent confuses bees searching for traditional sweet floral aromas, causing them to bypass the area. The potent fragrance acts as a barrier, especially when the plants are grown in dense groupings.
Wormwood (Artemisia absinthium), a perennial herb, produces an acrid, bitter scent due to compounds like thujone. This strong, non-floral aroma is not recognized by bees as a nectar source, making it excellent for boundary planting. The bitter compounds may also signal a lack of nutritional value, discouraging foraging.
Certain varieties of geraniums (Pelargonium species) function as bee deterrents due to their flower characteristics. Bees are less attracted to red flowers because they cannot perceive the color red clearly. Many ornamental geranium cultivars have double-petaled blooms that physically obscure the flower’s center. This makes the pollen and nectar difficult for the bee to access, leading them to seek more rewarding flowers elsewhere.
Maximizing Repellent Effectiveness
To maximize the deterrent effect, strategic placement and maintenance are more important than simply growing plants in a garden bed. The goal is to create a physical and aromatic barrier between insects and the space you wish to protect, such as a patio or outdoor kitchen. This requires concentrating plants in high-traffic areas where human-insect interaction is most likely to occur.
Potted plants are especially useful for this purpose, as they can be moved directly next to seating areas, doorways, or garbage receptacles, which are prime targets for scavenging wasps. Creating a dense, low-growing hedge of aromatic herbs, such as mint or basil, around the perimeter of a deck establishes a continuous wall of repellent scent. The density of the planting matters, as a single plant will have a negligible effect compared to a concentrated grouping.
The release of volatile oils can be mechanically enhanced through basic maintenance techniques. Gently crushing or bruising a few leaves of herbs like basil or peppermint releases a concentrated burst of the active compounds into the air, amplifying the repellent effect right before a gathering. This action is useful for herbs whose scents are not strongly released by the sun alone.
For perennial plants, consider planting them in a location that receives full sun, as the heat encourages the evaporation of the essential oils, increasing their reach. However, for herbs like mint that spread aggressively, using containers is advisable to control growth while still allowing for strategic placement. Regularly pruning and harvesting the plants promotes new growth, ensuring a consistent supply of fresh, potent foliage.