Society Garlic (Tulbaghia violacea) is a perennial herb often cited as a natural remedy for keeping mosquitoes away. It is widely planted due to the common belief that its distinctive, pungent aroma creates a natural barrier against biting insects. The central question for many is whether this popular claim holds up to scrutiny, requiring an examination of the plant’s chemical mechanism and available scientific evidence.
Characteristics of Society Garlic
Society Garlic is a clumping, herbaceous perennial native to the rocky grasslands of southern Africa. It is easily identified by its narrow, gray-green, grass-like leaves that grow in dense tufts up to a foot tall. In warmer months, the plant produces slender stalks topped with clusters of star-shaped, lilac-pink or purple flowers. As a member of the Amaryllidaceae family (which includes onions and culinary garlic), it shares a characteristic sulfurous scent when the leaves or roots are bruised.
The Chemical Basis for Repulsion
The proposed repellent mechanism relies on the volatile organic compounds (VOCs) released by the plant. When the tissue is damaged or crushed, an enzymatic reaction produces volatile sulfur compounds, which create the strong, distinct garlic-like odor. This scent is hypothesized to confuse or overwhelm the sensitive olfactory receptors of mosquitoes.
Mosquitoes rely on smell to locate hosts by detecting carbon dioxide and body odors. The plant’s aroma is theorized to mask these attractants, making the immediate area unpleasant. This deterrent effect depends on the continuous release of airborne molecules, but when the plant is undisturbed, the release is passive and highly localized.
What Scientific Studies Show
Concrete scientific data on the mosquito-repellent power of the living Tulbaghia violacea plant is scarce. Researchers have focused instead on extracts and essential oils from its close relative, common garlic (Allium sativum). Studies using concentrated garlic extract in traps showed a reduction in attracted mosquitoes compared to controls.
However, concentrated garlic oil applied to the skin provides only a short window of protection, typically lasting about 30 minutes. This suggests that volatile compounds must be present in high concentration to be effective, usually achieved only by crushing the material or extracting the oil. Consuming garlic offers no significant systemic protection against mosquito bites in controlled trials. Therefore, the simple presence of an unbruised Society Garlic plant offers only minimal, highly localized relief.
How to Deploy the Plant for Mosquito Control
Despite the limited evidence for the undisturbed plant, homeowners can utilize Society Garlic to maximize any potential localized effect. The sulfurous odor is only strongly emitted when the foliage is damaged. Active release of the oils is necessary to achieve the concentration of volatile compounds needed to potentially confuse nearby mosquitoes.
Maximizing Localized Effect
To maximize the plant’s potential, homeowners should focus on active release:
- Plant the herb in dense clusters near gathering areas, such as patios, decks, or entryways, to concentrate the natural aroma.
- Actively crush a few leaves to immediately release volatile compounds into the air.
- Place potted plants directly on outdoor tables where they can be easily disturbed.
- Position plants in high-traffic areas where foliage is likely to be brushed against.