The plant commonly sold as a Citronella Plant is typically a fragrant scented geranium (Pelargonium citrosum ‘Van Leenii’). It is marketed as a mosquito repellent because its foliage releases a strong lemon-like scent caused by the chemical citronellal. While commercial citronella oil comes from lemongrass (Cymbopogon nardus or C. winterianus), the geranium variety is popular for its ease of growth and pleasant aroma. Maximizing the benefits of this plant requires understanding how to properly cultivate, place, and actively use its leaves.
Essential Care and Cultivation Requirements
The citronella geranium thrives in warm climates, requiring a balance of sun, soil, and moisture. For robust growth, the plant needs full sunlight, meaning a minimum of six hours of direct sun exposure daily. In intense summer heat, afternoon shade can prevent leaf scorching.
Choosing the right container or planting location is important, as this plant is susceptible to root rot in soggy conditions. It requires a well-draining soil mix, ideally one rich in organic matter. Water the plant deeply only when the top one to two inches of soil feel dry, allowing the soil to dry slightly between waterings.
Consistent pruning during the active growing season helps maintain a bushy shape and encourages new growth. Pinch back the growing tips and remove any leggy or dead foliage. This maintenance ensures the plant remains dense and healthy.
Utilizing the Plant for Passive Pest Control
The citronella plant’s reputation as a bug deterrent stems from the volatile oils in its leaves. When the plant sits passively on a patio, the oils are not diffused in high enough concentration to create a protective barrier. The scent must be released manually to offer any noticeable effect.
For passive control, strategic placement is the most effective approach. Position potted plants near high-traffic areas, such as seating arrangements or entryways, where people frequently brush against them. Physical contact crushes the foliage slightly, releasing the signature lemony scent into the immediate vicinity.
The scent can mildly interfere with a mosquito’s ability to locate a host by temporarily masking human odors. For a boost in effectiveness, gently rustle the leaves just before spending time outdoors. This action releases citronellal vapors, creating a small, short-lived aromatic cloud that may offer minimal local deterrence.
Harvesting and Active Topical Use
To access the full potential of the plant’s essential oil compounds, the leaves must be harvested and physically manipulated. The best time to harvest foliage is in the early morning after the dew has dried, when the concentration of volatile oils is often at its peak. Use clean, sharp shears to cut mature leaves from the outer portion of the plant, taking care not to strip the plant completely.
For immediate, active application, crush a handful of freshly cut leaves between your palms to rupture the oil glands. Once the oil is visible, rub the resulting pulp directly onto exposed areas of your body. This process applies the highest possible concentration of citronellal directly to the skin, offering a temporary, localized deterrent effect.
Before applying the crushed leaves liberally, perform a small patch test on a discreet area of skin. The essential oils can cause irritation or an allergic reaction in some individuals.
Other Uses
Harvested leaves can be dried completely and used in homemade potpourri or animal bedding for a pleasant scent. Alternatively, fresh, crushed leaves can be steeped in a carrier oil, such as olive or jojoba oil, to create a basic infused oil for topical use.
Preparing the Plant for Winter Survival
The citronella geranium is a tender perennial and cannot survive freezing temperatures. Outside of USDA Zones 9 through 11, it is typically grown as an annual. To keep the plant alive for the next season, bring it indoors before the first frost, ideally when nighttime temperatures consistently drop below 45°F.
Before moving the plant, prune it back significantly by cutting the stems just above a leaf node to encourage bushier regrowth. Thoroughly inspect the foliage and soil for pests, such as whiteflies or mealybugs, and treat them before bringing the plant indoors. Once inside, place the plant in a bright location, such as a south-facing window, where it can receive several hours of direct sunlight daily.
During indoor dormancy, the plant requires less water, so allow the soil to dry out more substantially between waterings.
Propagating for Next Season
An alternative strategy for long-term ownership is to take three-to-five-inch stem cuttings in the fall and root them in moist, well-draining soil. These smaller cuttings are easier to manage indoors and provide a backup supply of new plants for the following spring.