The citronella plant, a botanical charmer renowned as much for its aromatic charm as its supposed role in the fight against pests—moreso mosquitoes—is an easy-to-care-for floral jewel that you would want to have at your home or any of your spaces. Imagine brushing against a plant whose leaves a spurt of citrus-scented aroma, wouldn't that be a sensory delight? Well, that is the essence of the citronella plant. Plus, it is simply an all-round plant.
Also called Pelargonium citrosum, the citronella whose distinctive lemony aroma always wafts through the air at the slightest touch; offering more than just a pleasant fragrance as it also repels mosquitoes, is often a source of interest for gardeners, herbalists, and general plant enthusiasts due to its manifold benefits. Unlike the typical garden introductions that focus solely on pest control, this aromatic perennial brings to the table versatile applications and an unassuming beauty that enhances both outdoor and indoor spaces.
Understanding the Citronella Plant
Scientifically called Pelargonium citrosum, citronella belongs to the Geraniaceae family and is often referred to by various names including mosquito plant, Citrosa geranium, citronella scented geranium, and lemon-scented pelargonium. Its scent is more lemony than it is citronella-like. Despite its common name which implies a connection to true citronella grass, Pelargonium citrosum is botanically distinct. It is a perennial subshrub with fragrant leaves that, when crushed or disturbed, emit a citrus-like scent reminiscent of citronella.
Taxonomically, this plant has an interesting history. Both Pelargonium and Geranium genera belong to the family Geraniaceae. Carl Linnaeus, the Swedish naturalist who created the binomial nomenclature for naming organisms, originally included all species in one genus, Geranium. They were later separated based on distinct characteristics, with Pelargonium distinguished by having seven stamens or anthers. The specific sobriquet 'citrosum' refers to the chemical substance citronella that produces the characteristic lemon scent of the plant. Also, read more about the 8 most fragrant indoor plants here.
The citronella plant is sometimes listed as Pelargonium x citrosum, indicating its hybrid nature. Its formula hybridae, according to some botanical sources, is Pelargonium crispum x Pelargonium x limoneum Sweet. Still, several synonyms for it exist, including Pelargonium citriodorum, Pelargonium 'Citrosa', and Pelargonium 'Van Leenii'.
Clearing the Confusion - Citronella Plant vs. Citronella Grass
Many people often confuse the citronella plant (Pelargonium citrosum) and true citronella grass (Cymbopogon species). While both plants share mosquito-repelling properties and similar names, they are entirely different species. Citronella grass belongs to the Poaceae family and includes species like Cymbopogon nardus and Cymbopogon winterianus, which are the primary sources of commercial citronella oil.
On the other hand, the mosquito-repellant citronella plant (Pelargonium citrosum) is a scented geranium that was reportedly developed by Dutch horticulturist Dirk Van Leenan, giving rise to the name Pelargonium citrosum 'Van Leenii'. This plant contains compounds that mimic the scent of citronella but is botanically unrelated to true citronella grass. This distinction is insightful for those seeking specific mosquito-repellent plants for their landscapes.
Origin, History, and Distribution of the Citronella Plant
The history of using plants that repel mosquitoes dates back thousands of years across many civilizations. While the true citronella has been historically in Asian cultures, the Pelargonium genus has its own elaborate history of use in African traditions. Indigenous populations in Africa often used different Pelargonium species for their aromatic and medicinal properties.
True citronella grass originates from tropical regions of Asia. But the citronella plant has its roots in African species. Pelargonium citronellum - which is very closely related to Pelargonium citrosum - grows naturally in regions in the southeastern Western Cape of South Africa. It is commonly found on the northern foothills of the Langeberg Mountain Range, typically growing near streams in well-drained soil. The citronella plant's hybrid origins, therefore, are traced back to selective breeding efforts, likely involving African Pelargonium species like Pelargonium citronellum. Its cultivated status means it thrives under human care rather than in the wild, thus it is a garden-centric hybrid.
Unlike ancient medicinal herbs with millennia of folklore, the citronella plant, being a modern creation born from horticultural experimentation, was engineered to amplify the citronellal compounds found in its geranium relatives. And, while its precise lineage remains debated, its ancestors hail, as noted, from South Africa's Cape region which is a biodiversity hotspot for Pelargonium species. Introduced to global gardens as a mosquito-fighting plant, the citronella plant quickly became a poster child for plants that deter mosquitoes, despite continuing debates about its full efficacy.
Appearance and Seasonal Changes of the Citronella Mosquito Plant
This mosquito-repelling plant displays distinctive characteristics that make it recognizable among other garden plants. it features simple, alternately arranged leaves with conspicious veins on their undersides. The leaves are palmately shaped with sharply pointed lobes and are covered sparsely with small hairs and glandular hairs that release the plant's signature scent when touched.
The flowering period for this mosquito-fighting plant occurs during spring and summer, from August to January in its native South Africa, with peak blooming typically in early summer between September and October. The flowers are pink-purple with a conspicuous dark marking on the two larger upper petals, while the three smaller lower petals lack markings. This flowering pattern adds ornamental value to the plant's already useful mosquito-repelling properties.
About the Natural Habitat of the Citronella Mosquito Repellent Plants
In its natural environment, Pelargonium citronellum, the closest relative to this citronella plant, is considered rate but not threatened. It requires a specialized habitat and occurs in scattered populations throughout its native range. Understanding the natural growing conditions of these mosquito-repellent plants, therefore, helps gardeners recreate those optimal growing environments when cultivating them in their homes.
The plants that keep away mosquitoes often develop their repellent properties as defense mechanisms against pests in their native habitats. The citronella plant has, therefore, adapted to growing in conditions that include well-drained soil and adequate sunlight; factors that stimulate the production of the aromatic oils that give the plant its characteristic scent and mosquito-repelling properties.
Is Citronella a Perennial? Its Growth Habits and Characteristics
Often, many wonder: Is citronella a perennial? Well, the answer depends largely on a region's climate. The Pelargonium citrosum is technically a perennial subshrub in USDA zones 9-11, where it can survive year-round and grow up to 2 meters in height with a spread of about 1 meter. In these warm climates, the plant develops a woody base over time, enhancing its perennial nature.
However, in cooler regions (zones 8 and below), the question "Is citronella a perennial" question becomes a tad difficult, as the plant cannot survive frost. Growers in these areas typically grow it as an annual or as a container plant that can be brought indoors during winter months. This flexibility makes growing citronella plants accessible to gardeners in various climatic conditions.
Citronella Plant Care - Cultivating Your Mosquito-Fighting Plant
Successful citronella plant care begins with understanding its basic requirements. These plants that prevent mosquitoes are relatively undemanding, thus they are suitable for both beginners and experienced gardeners. Their adaptability adds to their popularity as both functional and ornamental additions to gardens.
Citronella Plant Light, Soil, and Water Requirements
When growing citronella, providing the right light conditions ensures healthy plants with stronger scents and better mosquito-repelling properties. The citronella plant thrives in direct sunlight but can also tolerate partial shade, thus, it is versatile for different garden locations. For optimal growth and oil production, a position that receives at least 6-8 hours of sunlight daily is ideal.
Regarding soil, the citronella plant prefers moist, rich, and well-drained potting mix. Heavy, waterlogged soils can lead to root rot and should be avoided. If your garden has clay-heavy soil, amending it with organic matter improves drainage and creates better growing conditions for these plants that will keep away mosquitoes from your home.
Watering should be done whenever the top layers of soil become dry, typically about twice weekly depending on climate conditions. Overwatering should be avoided as it may cause root rot, a common issue with many aromatic herbs. During hot summer months, the plants may require more frequent watering, while during cooler periods, watering frequency can be reduced.
Fertilization and Maintenance for Healthy Mosquito-Repelling Plants
For hearty growth, fertilize your citronella plant with granular compound fertilizer or organic options like chicken, goat, or sheep manure every two weeks. Liquid nutrients can also be effective when applied according to package directions. Regular fertilization ensures that the plant produces abundant foliage with high concentrations of aromatic oils that enhance its mosquito-repelling capabilities.
Maintenance for these plants that repel mosquitoes includes occasional pruning to maintain shape and encourage bushier growth. Removing spent flowers promotes continued blooming throughout the season. Additionally, 'fluffing up' the plant before outdoor gatherings releases more of its mosquito-repelling scent into the air, enhancing its practical benefits when you need them most.
The Many Hats of Citronella Plants
The versatility of the citronella plant goes far outside its well-known mosquito-repelling properties. This multi-functional plant also offers applications in culinary arts, medicinal treatments, and aromatherapy, all of which are applications that make it a valuable addition to any garden or home.
Citronella as Plants That Keep Away Mosquitoes
Among the many plants that keep away mosquitoes, the citronella plant is touted to stand out for its effectiveness. The plant works as a natural mosquito deterrent through its strong lemon scent, which masks the human odors that attract flying pests. For maximum effectiveness as a mosquito repellent plant, place several plants around seating areas or paths where people frequently gather.
However, while citronella plants are prominent among mosquito-fighting plants, they work best when combined with others that are equally repellent, in a comprehensive garden plan. The plant's efficacy can be heightened by occasionally brushing against the foliage to release more of the aromatic compounds, or by rubbing the leaves on the skin, albeit after testing for sensitivity, for more direct protection.
Culinary Applications of the Citronella Plant
Aside from its role as one of the plants that repel mosquitoes, the citronella plant offers gastronomic possibilities that many often overlook. The leaves can be used as a culinary herb, adding a citrusy flavor to teas and desserts. The scented geranium leaves can flavor cakes, butter, jellies, ice cream, and other dishes including meat and salad preparations.
When used in baking, a common technique involves placing the leaves at the bottom of the baking pan before pouring in the batter. After baking, the leaves are removed, but their distinctive flavor becomes infused throughout the baked goods. For tea preparation, dried leaves can be crushed and steeped in boiling water, creating a refreshing beverage with subtle citrus notes.
Medicinal and Aromatherapy Benefits
Historically, Pelargonium species have been used in traditional medicine, particularly in their native Africa. They have been employed to treat various conditions including intestinal, kidney, and respiratory issues, wounds, fevers, and other health ailments. While modern medical research on Pelargonium citrosum specifically is limited, the broader genus has documented antimicrobial and anti-inflammatory properties.
In aromatherapy, the citronella plant's oil is used as a relaxant. The uplifting, citrus fragrance promotes positivity and improved mood, making it valuable beyond its common role as a plant that deters mosquitoes. The pleasant scent can be enjoyed by crushing fresh leaves, using dried leaves in potpourri, or incorporating the plant into fragrant garden designs where brushing against the foliage releases its fragrant compounds.
Landscaping With Citronella Plants
Incorporating mosquito-repellent plants like citronella into landscape design creates functional outdoor spaces that remain comfortable even during mosquito season. The citronella plant's bushy growth habit and attractive foliage make it suitable for various garden applications beyond mere utility.
As an ornamental, the citronella plant shines in containers, borders, and patio gardens. Its lobed textured foliage and pinkish-lavender flowers add visual intrigue, while its scent elevates it among other plants that keep away mosquitoes—or so gardeners hope! Although studies suggest its mosquito-repelling power is milder than concentrated citronella oil, its presence in a garden layered with other mosquito-repellent plants like lavender, marigolds, and basil creates a synergistic defense.
Still, for container gardening, the citronella plant adapts well to pot culture, making it ideal for patios, decks, and balconies where mosquito control is often most needed. Its moderate size works well in medium to large containers, and their adaptability to container growing is particularly valuable in regions where the question: "Is citronella a perennial?" is often answered negatively, due to cold winters since these potted plants can be moved indoors for protection.
In landscape beds, citronella plants can be positioned near seating areas, entryways, or windows to maximize their mosquito-repelling benefits. Their attractive form and subtle flowers complement other garden plants while providing functional pest control. The plants perform especially well near water features, where they help control mosquitoes that might otherwise breed in the water.
Companion Planting With Other Mosquito Fighting Plants
For enhanced mosquito control, combine citronella plants with others that repel these pests such as lavender, rosemary, basil, marigolds, and catnip. Therein, its scent will be paired with rosemary's piney scent, basil's spicy undertones, and the perky radiance of marigolds in a diversity that not only confuses pests but also creates a multi-layered aromatic shield, which in turn creates a more comprehensive defense system while adding variety to the garden. Combining these different repellent plants with varying active compounds also creates a more effective barrier than any single species alone would.
The citronella plant also benefits pollinators, as it is safe for bees and does not repel beneficial insects like spiders. Hummingbirds and butterflies are similarly unaffected by the plant's repellent properties, making it an environmentally friendly choice for a mosquito-repellant that does not disrupt beneficial garden ecology. This selective repellent quality—deterring only biting insects like mosquitoes and flies—makes it particularly valuable in wildlife-friendly gardens. Most importantly, as one of nature's original mosquito-fighting plants, citronella connects modern gardeners to ancient plant wisdom, showing that sometimes the most effective solutions have been growing around them all along.
Feature image by @treatsbytara, header image by @v_heg.
