The plant sold as the “citronella plant” is actually a scented geranium, Pelargonium citrosum ‘Van Leenii’. This perennial subshrub, often called the mosquito plant, is a hybrid known for its ruffled, lacy foliage and strong lemon scent. Although its name suggests a link to commercial citronella oil (derived from Citronella Grass), this scented geranium is the variety most commonly cultivated by home gardeners for its aromatic qualities and ease of care.
Cultivating the Citronella Plant
The citronella plant thrives in full sun, requiring at least six hours of direct light daily. In regions with intense summer heat, the plant benefits from afternoon shade to prevent scorching. An ideal compromise is a spot that receives morning sun and protection during the hottest part of the day.
The plant requires well-draining soil, adapting well to sandy or loamy mixtures. Proper drainage is important because the scented geranium is susceptible to root rot in overly saturated conditions. For potted specimens, a standard container mix works well, often amended with organic matter.
Water only when the top inch or two of soil feels dry. While established plants tolerate some drought, consistent irrigation is needed during the active growing season. Ensure excess water drains completely from the container to avoid standing water.
As a tender perennial, the citronella plant is not cold-hardy outside of USDA Zones 9 through 11 and is treated as an annual elsewhere. To overwinter, bring the plant indoors before nighttime temperatures drop below 45°F. Prune the stems back by up to one-third, cutting just above a leaf node, and place it in a sunny, south- or west-facing window.
Indoors, water less frequently, allowing the soil to dry slightly more between applications. Reduced light and cooler temperatures encourage semi-dormancy, helping the plant survive winter. Regular pruning of growing tips encourages a bushier appearance and prevents the plant from becoming leggy.
Maximizing the Plant’s Repellent Properties
The plant’s reputation as an insect deterrent stems from volatile essential oils stored in its leaves. These oils contain repellent compounds like geraniol, citronellol, and linalool. However, the plant does not automatically release sufficient oil into the air to repel insects over a wide area.
The scent is only released when the leaves are physically disrupted (crushing, brushing, or tearing). A stationary, untouched plant offers little more than a localized burst of fragrance. Studies show that the plant’s ability to repel mosquitoes in an open area is often insignificant.
For personal protection, the most effective method is rubbing fresh, crushed leaves directly onto the skin. This transfers concentrated compounds, creating a short-term deterrent. Note that the oil may cause skin irritation and should be tested on a small patch of skin first.
Optimal placement is near seating areas, along walkways, or on patios where the plant is likely to be brushed against. This ensures movement or contact releases the aroma. While not a broad-area shield, its strong, lemon-like fragrance provides a pleasant aromatic experience.
Propagating New Plants
The citronella plant is easily multiplied using stem cuttings, which reliably produce an identical clone. The best time to take softwood cuttings is during spring or early summer when the plant produces new, non-woody growth. Use clean, sharp shears to take a cutting three to five inches long.
The cutting should include two or three leaf nodes, where roots will form. Remove all but the top two or three leaves to reduce moisture loss and focus energy on root development. Dipping the cut end into rooting hormone powder is optional but can speed up the process and increase success.
Insert the cutting into moist, well-draining potting soil, burying the bottom node or two. Place the pot in bright, indirect light and keep the soil consistently moist. Roots typically establish within three to four weeks, after which the new plant can be treated like a mature specimen.