Citronella grass is a fragrant ornamental plant widely sought after for its natural ability to deter insects. This tall, clump-forming grass is a source of the essential oil used in many commercial insect-repelling products. The primary appeal lies in the strong, lemon-like scent that releases a volatile oil known to confuse and discourage mosquitoes. Finding the correct species and knowing how to care for it ensures you get the maximum benefit from its aromatic foliage. This plant offers a pleasant, organic alternative for managing pests in outdoor living spaces.
Identifying the Correct Citronella Grass Species
The term “citronella plant” often causes confusion because two very different plants are sold under this name. True citronella grass belongs to the Cymbopogon genus, which includes Cymbopogon nardus (Ceylon citronella) and Cymbopogon winterianus (Java citronella). These species are the sources for commercial citronella oil, containing high concentrations of insect-repelling compounds like citronellal and geraniol.
True citronella grass is a tall, clumping perennial that can reach heights of five to eight feet in warm climates. Its foliage consists of long, thin, bright green blades that have a characteristic reddish tint at the base of the stems. The aromatic oil is contained within the leaves and stems, requiring the plant material to be bruised or crushed to release the strong scent.
The common imposter is often labeled as the “Mosquito Plant” or citronella geranium (Pelargonium citrosum). This plant has soft, lacy, lobed leaves and a bushy, shrub-like growth habit, growing only about two to three feet tall. While Pelargonium citrosum does emit a lemon scent when disturbed, it contains much lower levels of effective citronella compounds and is largely ineffective at repelling mosquitoes. When purchasing, always check the label for the scientific name Cymbopogon to ensure you are buying the correct, oil-producing grass.
Where to Purchase Citronella Grass
The search for true citronella grass (Cymbopogon species) often begins at local garden centers and specialized plant nurseries. These locations are generally the best source for established plants, as they carry larger, healthier stock grown specifically for the ornamental market. The optimal time to purchase is in late spring or early summer, after the final threat of frost has passed, which aligns with the start of the primary growing season.
Large big-box retailers and home improvement stores also stock citronella grass, though it is frequently sold as an annual in cooler climates. While convenient, the quality can vary, so inspect the plants closely for signs of a healthy root system and vibrant color. Be especially cautious at these locations, as they are the most likely to mistakenly display the ineffective Pelargonium citrosum alongside the true grass.
Online seed and plant suppliers offer another viable option, particularly for sourcing specific cultivars or purchasing in bulk. You can purchase established plugs or small starter plants, which are easier to ship and transplant. Buying seeds is also an option, but Cymbopogon is typically propagated vegetatively by dividing the clumps. Regardless of the vendor, ensure the plant you select has bright green foliage, no yellowing leaves, and appears vigorous.
Post-Purchase Care and Placement
Citronella grass thrives under conditions that mimic its tropical origin, making proper placement and care essential. The plant requires a location that receives full sun, ideally six or more hours of direct sunlight daily, to encourage robust growth and oil production. In regions with intense summer heat, the plant may benefit from afternoon shade to prevent scorching of the leaf tips.
The grass needs well-draining soil and consistent moisture; the soil should be kept moist but never soggy. In containers, which are common outside of its perennial hardiness zones, select a pot with excellent drainage. Water thoroughly whenever the top inch of soil feels dry. Regular watering, especially during dry spells, is necessary to support its large, clumping form.
To leverage the insect-repelling scent, strategically place the potted grass near outdoor seating areas or entry points where mosquitoes are a concern. The plant does not naturally release enough volatile oil into the air to create a protective barrier on its own. To activate the aroma and release the maximum amount of citronellal, you must brush against or gently crush a few of the blades. Since citronella grass is a tropical perennial, hardy only in USDA Zones 10 to 12, it must be treated as an annual or brought indoors before temperatures drop below freezing in most temperate climates.