The citronella plant, known for its lemony scent, is often marketed as a natural insect repellent. Many consider growing these plants indoors for their aromatic qualities. While commonly called “citronella plants,” there are two main types: Citronella Grass (Cymbopogon nardus or Cymbopogon winterianus) and the Citronella Geranium (Pelargonium ‘Citronella’). The scented geranium is more commonly grown as an ornamental plant. Understanding their specific needs and actual indoor repellent capabilities is key for successful cultivation.
Growing Citronella Indoors
Cultivating citronella plants indoors is feasible but requires specific environmental conditions. These plants thrive with ample sunlight, ideally receiving six to eight hours of direct sun daily. A south-facing window is often the most suitable location. If natural light is insufficient, especially during winter, supplement with a grow light to prevent leggy growth.
Citronella plants need adequate space, reaching up to two feet tall and wide for the geranium variety. Choose a pot at least 12 inches deep and twice the width of the root ball. These plants prefer cooler conditions, ideally between 60°F to 70°F (15°C to 21°C). While they tolerate warmer indoor temperatures, extreme heat can stress the plant.
Essential Care for Indoor Citronella
Providing precise care is important for indoor citronella plants to maintain their health and characteristic fragrance. Watering should be consistent but careful; the soil needs to be kept moist but never waterlogged to prevent root rot. It is advisable to allow the top inch of soil to dry out between waterings before rehydrating the plant. Well-draining soil is crucial for citronella, with a mix of perlite, peat moss, and sand often recommended, or a standard potting mix designed for good drainage.
Humidity preferences are moderate. While not overly sensitive, extremely dry indoor air can be detrimental. Occasional misting or placing the pot on a pebble tray with water can help increase ambient humidity. Fertilization is not always strictly necessary, but a balanced, water-soluble houseplant fertilizer can be applied once a month during the active growing season, from spring through summer.
Pruning is also beneficial, as it encourages a bushier growth habit and helps maintain the plant’s shape. Removing dead or damaged leaves and trimming back stems by about one-third, cutting just above a leaf node, promotes new growth and overall plant vigor.
Citronella as an Indoor Insect Repellent
A common belief is that a citronella plant indoors will effectively repel mosquitoes and other insects. However, this is largely a misconception. The plant itself does not release enough repellent compounds into the air to deter insects in a room. Its characteristic lemony scent, containing compounds like citronellal, citronellol, and geraniol, is primarily released when the leaves are crushed or bruised.
Therefore, for any repellent effect, one would need to actively bruise or rub the foliage, which is not practical for continuous indoor insect control. The effectiveness often associated with “citronella” comes from concentrated citronella oil, extracted from grass varieties and used in products like candles, sprays, or lotions. These products are formulated to release volatile compounds more effectively. While the plant can add a pleasant citrusy aroma when disturbed, it serves more as an ornamental plant indoors than a standalone insect repellent.
Safety Concerns
When growing citronella plants indoors, be aware of potential safety concerns, especially for households with pets or small children. The citronella plant, particularly the Pelargonium ‘Citronella’ variety, is toxic to cats and dogs if ingested. Ingestion can lead to symptoms such as vomiting, diarrhea, and depression.
For humans, while citronella oil is generally safe topically in small amounts, direct ingestion of plant material can cause mild irritation. Keep citronella plants out of reach of curious children and pets to prevent accidental ingestion. Placing them on high shelves or in inaccessible rooms can help mitigate these risks.