Mosquitoes are vectors for various diseases, prompting many to seek effective ways to protect their outdoor spaces. While synthetic chemical repellents are highly effective, certain flowers and herbs offer a natural, non-toxic approach. These plants contain compounds that mosquitoes dislike, providing a localized deterrent when strategically placed around patios and entryways.
Identifying Key Repellent Plants
A few specific flowers and herbs are recognized for their mosquito-deterring properties. French Marigolds (Tagetes patula) are frequently planted options, featuring brightly colored blooms in shades of yellow, orange, and red. These easy-to-grow annuals release a strong, pungent odor from their flowers and foliage that mosquitoes tend to avoid. This powerful scent allows marigolds to function well as border plants or when grouped in containers near gathering spots.
The Citronella Geranium (Pelargonium citrosum), often marketed as the “Mosquito Plant,” is distinguished by its deeply lobed leaves and distinctly citrusy aroma. This scented geranium is not the true source of commercial citronella oil, but its fragrance is similar. Citronella Geraniums are frequently grown in pots and thrive in full sun or partial shade.
Lavender (Lavandula) is a hardy, drought-resistant perennial effective at deterring mosquitoes. Varieties with a higher camphor content, such as ‘Grosso’ or ‘Provence,’ tend to be the most potent insect repellents. The scent comes from essential oils concentrated in the foliage and flower spikes. Lavender thrives in sunny spots with good drainage, and its aroma is disliked by many flying insects.
How Plant Compounds Deter Mosquitoes
The repellent effect of these plants stems from the release of volatile organic compounds (VOCs) stored within their tissues. Mosquitoes are primarily attracted to the carbon dioxide and lactic acid that humans exhale and secrete, and these plant compounds work by disrupting the insect’s ability to detect those attractants. The strong, often unpleasant, aromas effectively mask the human scent trail, making it difficult for mosquitoes to locate a host.
Marigolds contain compounds called pyrethrins, which are natural insecticides. These compounds are closely related to pyrethrum, a substance historically extracted from chrysanthemum flowers and used in commercial pesticides. Since these chemicals are toxic to mosquitoes and other insects, the plants are often avoided in the garden.
Lavender’s repelling action comes largely from the compound linalool, an alcohol that has been shown to interfere with the mosquito’s olfactory system. Similarly, the Citronella Geranium releases a scent containing citronellol, which mimics the aroma of true citronella oil. These specific chemicals provide the localized protective effect.
Maximizing Repellent Plant Effectiveness
Simply planting repellent flowers in a garden bed offers limited protection because the release of essential oils is often too diffuse to create a meaningful barrier. Strategic placement is necessary to maximize effectiveness. Positioning potted plants directly near seating areas, such as on a patio table or flanking a doorway, concentrates the repellent scent where protection is needed. This localized application creates a small, scented bubble that helps deter insects.
For many of these plants, including Lavender and the Citronella Geranium, the repellent effect is not released passively. Actively crushing or rubbing the leaves is often required to break the oil glands and release a concentrated burst of compounds. This manual activation releases the strongest dose of chemical deterrents, which can then be rubbed directly onto the skin as a mild, temporary repellent.
Using container gardening allows these species to be moved closer to areas of activity, such like barbecue spots or children’s play zones. While botanical repellents offer localized protection, they do not provide the complete, area-wide eradication associated with commercial chemical treatments like DEET.