Citronella Plant Easy Guide: How to Grow the Mosquito Plant

When you think of citronella, it likely stirs up memories of refreshing citrusy scents on a hot summer’s evening, the trusty barrier against pesky insect bites. But citronella plants are diverse and multifunctional species, with much more to offer than just their smell.

Used in food, cosmetics, medicine, and much more, these undemanding yet worthwhile plants are some of the simplest plants to grow, rewarding gardeners with their pretty pink petals long throughout spring and summer. 

Here is our very easy guide to growing and caring for your own citronella plant, both indoors and outdoors. 

What is Citronella Pelargonium? 

 Pelargonium citronellum, also known as Pelargonium citrosum, is a flowering tender perennial shrub belonging to the Pelargonium genus which contains around 280 species in total. They can be both herbaceous or woody, depending on their age. Most commonly known as citronella pelargonium, mosquito plant, or simply as citronella, this plant is famed for its distinctive citrus fragrance and pretty pink blooms. 

Citronella is native to temperate and humid tropical and subtropical regions of Africa, particularly South Africa, and some parts of Asia. In its natural habitat, citronella grows as perennial, but when cultivated in cooler northern climates it is treated as an annual, as it won’t survive freezing winter temperatures. 

These shrubs can grow vigorously, reaching heights of up to two meters and spreading around a meter wide when mature. As they age, these plants develop woody stems at the base, which branch out into dense, bushy, lime-green and deep green foliage.

Each leaf features irregular, jagged edges which appear similar to parsley leaves, and are covered in very tiny glandular hairs. It is this fine hair that contains the citrusy scent that citronella plants are famed for.

The scent is released when the leaves are touched or crushed. During the summer, citronella plants produce a beautiful spray of delicate, powder-pink to lilac-coloured blooms, which protrude proudly atop singular stems.

Each flower is made up of five irregularly spaced petals, and two of these petals are often decorated with areas of a deeper colour. The unusual foliage, charming flowers, and pleasant scent make citronella a popular addition to many summer gardens.

The History of Citronella Pelargoniums

Citronella plants belong to a diverse group of plants which are colloquially known as scented leaf pelargoniums. There are hundreds of varieties of scented leaf pelargoniums, each with its own unique aroma, ranging from sweet and chocolatey, to minty, to fruity, and even spicy or musky. 

Despite long being recognised as a scented pelargonium, it wasn’t until 1983 that the Pelargonium citronellum was formally identified as an individual species. The Pelargonium citronellum takes its name from a chemical substance called citronella, which has a distinct lemony scent similar to that given off by this particular scented leaf pelargonium, and thus the plant is best known simply as citronella. 

Strictly speaking, however, this moniker isn’t wholly appropriate for this pelargonium. True citronella plants actually belong to the grass family and are known as lemongrass, and are in fact no relation to citronella pelargonium. The only similarity between the two is their citrusy scents. 

Uses and Benefits of Citronella Pelargonium

Beautiful blossoms and uplifting aromas aside, citronella is one of the most practical and versatile plants to grow! Here are just a few ways that you might choose to use your plant. 

Mosquito Repellant? Does it really work? 

Perhaps the most common use for citronella is as a mosquito repellant. And whilst many insects are indeed averse to strong, lemony smells, the citronella pelargonium doesn’t contain the ‘true’ citronella oils of the citronella grass. It is only the grass plant, and not the pelargonium, whose oils are extracted for use in chemical insect repellants.

It is thought that the citrus scent of the pelargonium mimics the chemicals given off by true citronella, and has a similar, but weaker, deterrent effect, although there is much debate over its true efficacy. 

Many people report that crushing or rubbing the foliage on their skin does have some repellant effects, although this is anecdotal, rather than scientific. Simply having a citronella pelargonium nearby won’t be enough to deter mosquitos from biting. The leaves need to be crushed and rubbed on the skin to release the scent. And even then, the scent is short-lived, so repeated applications will be necessary.

Perfume and Cosmetics 

Scented pelargoniums, citronella included, are often used as an organic scent ingredient in many commercial and homemade cosmetics and perfumes. Because it is a natural ingredient, it rarely produces adverse reactions when applied to the skin, and is a great alternative to harsh chemical fragrances. 

Essential Oils and Pot Pourri 

The strongly scented leaves of citronella lend themselves perfectly to the essential oils used in aromatherapy, adding a refreshing and uplifting fragrance. The oils are extracted from the foliage to be used either alone or as part of a combination of oils for treatments. You can also dry out the leaves of your citronella plant to create a beautifully aromatic homemade potpourri to make your home smell heavenly.  

Food

Citronella foliage is edible and is often used as a fragrant herb added to cooking. It brings a delicate citrusy taste to both sweet and savoury dishes. It can also be used as a standalone flavouring for drinks and syrups. 

Companion Planting 

Similar to the way that the scented oils of citronella deter mosquitos from feasting on us when rubbed on our skin, citronella plants can also be used to deter harmful pests from feasting on our crops. Many gardeners grow citronella as a companion plant near to pest-prone vegetables such as tomatoes, acting as a natural alternative to pesticides. Their strongly scented foliage deters any would-be predators without harming any beneficial wildlife. 

Care guide

With so many potential uses, there’s no end to the benefits of growing your own citronella. Plus, scented pelargoniums are one of the easiest plants to grow, and will adapt effortlessly to both indoor and outdoor growing. They are an incredibly forgiving plant, perfect for horticultural novices and experts alike. Here is our simple guide to caring for your citronella. 

Growing Citronella Outdoors

From seedlings or young plants

Citronella pelargoniums are popular plants, and can young plants be readily purchased from most garden centres and nurseries. If you are planting outdoors, wait until the last frost has passed in late spring. If they are going to be grown in ground borders, leave about 20 inches of space around each plant to give the bushy foliage plenty of room to spread as it matures. Containers should be at least twelve inches deep and wide to comfortably accommodate their growth. 

Growing from seed

If you plan to grow your citronella from seed, the best time to sow them is in either early autumn or very late winter, so the seedlings have plenty of time to become established before the spring. Sow the seeds thinly into seed trays filled with loose compost and cover them with a very fine sprinkling of soil.

Position the tray indoors, somewhere with moderate light and a mild temperature. Keep the soil lightly moist until the seeds germinate in around three weeks. Once established, the seedlings can be transplanted into individual pots and kept away from direct sunlight near a window or in a greenhouse until late spring. Once the last frost has passed, they will be ready to transfer to their intended growing position. 

Soil

Citronella plants need loose and well-draining soil. Heavy soils retain too much water and citronella is prone to root rot if its roots are oversaturated. Add in some sand or light horticultural grit to improve drainage for your citronella.

Citronella plants also like relatively fertile soil, so whether planting in borders or containers, make sure you work plenty of extra organic matter into the substrate. Although they are not particularly fussy about pH levels, citronella tends to grow best in a slightly acidic substrate. 

Light 

Citronella plants grow best in full sun and need at least six hours of direct sunlight per day. Citronellas which don’t receive enough sunlight may become leggy as they stretch out to find more light, and they may struggle to flower, although they will still produce a strong citrus scent in their foliage.

In very warm climates, where the afternoon sun is very intense, try to position your citronella somewhere that receives a little afternoon shade. Your citronella will flower most prolifically when it receives full sun. 

Water

Citronellas are hardy plants and can tolerate a little drought during summer. That being said, they grow best in slightly humid conditions, so try to keep their soil evenly and lightly moist, whether growing in the ground or containers. Citronella is sensitive to being overwatered, so always wait for the top inch of soil to dry out between waterings. If the soil becomes too dry for prolonged periods, you may notice the bottom leaves becoming yellowed and wilted. 

Food

If you are growing your citronella for its beautiful blooms as well as its fragrance, make sure you add some additional fertiliser throughout spring and summer to encourage plenty of long-lasting flowers. Citronella isn’t a particularly hungry plant, so monthly feeds will be sufficient throughout the growing season, or even less frequently if growing in very fertile soil.

Potted plants will need slightly more food than border-grown plants. During autumn and winter, you won’t need to give your citronella any additional food.  

Pruning 

To encourage dense, bushy growth, you can pinch or prune off the tips of your citronella stems to redirect energy towards the foliage. Citronella grown in shadier spots will need regular pinching back to prevent them from becoming sparse and leggy. Periodically remove any fading or yellowing leaves and any spent flowers to keep your citronella looking its best and encourage more blooms long into late summer. 

Overwintering 

Winter care for your citronella plant depends on your local climate. Citronella is a tender perennial and will survive a mild winter outdoors. If you are lucky enough to live in a warmer climate, protect your citronella by mulching around the base if grown in borders, whilst container-grown citronellas can be temporarily moved to a more sheltered position in the garden. 

If you live in a colder climate, where temperatures regularly reach freezing or lower, it’s best to treat your outdoors citronella as an annual. They will die back after the first frost arrives, at which point, they can be dug up and disposed of. If you want to keep your outdoors-grown citronella safe for next season, dig it up well before the first frost arrives, making sure you keep the whole root ball intact.

Place it in a small pot filled with loose, fertile soil, and position it on a sunny windowsill indoors. Treat your citronella as a houseplant during the coldest months, with reduced watering and no fertiliser. Once the last frost has passed in late spring, you can transfer your citronella back to the garden.

Growing Citronella Indoors

For the most part, caring for an indoors citronella is much the same as caring for an outdoors citronella. They can happily live inside all year round and be treated as a houseplant, or you may wish to bring your outdoors citronella inside over winter. Here’s our easy guide to caring for citronella indoors. 

Pots 

Select a pot with plenty of drainage holes that will allow excess water to flow freely from the soil. The pot should be a good few inches wider in diameter than the plant, to accommodate for their fibrous roots and bushy foliage. You should aim to repot your citronella every couple of years to accommodate their increasingly woody roots and stems. 

Soil  

Indoors, your citronella will need a well-draining and fertile potting mix. A standard houseplant compost will be perfectly adequate, but you can give your plant a boost by working through some additional organic manner. Adding extra drainage materials such as perlite or vermiculite will protect your plant against root rot.

Light 

Just as outdoors citronella enjoys plenty of bright sunlight, your indoors citronella needs lots of bright, warm sunlight to thrive. Position your citronella on a sunny windowsill where it will receive at least six hours of sunlight per day. If the sun’s warmth is particularly intense during the summer, you could move it to a slightly more sheltered position or use a translucent voile to diffuse the light. 

Water

Much like outdoors citronella, indoor plants like evenly moist soil. Allow the top inch of soil to dry out between waterings, and make sure the excess water drains thoroughly afterwards. You can reduce the frequency of your watering during winter when your citronella is not actively growing. 

Food

As with outdoors citronella, feed your indoor plant sparingly throughout the spring and summer months to encourage plenty of pretty pink flowers. You won’t need to feed it during autumn and winter. 

Propagating your Citronella plant 

Citronella plants are incredibly easy to propagate, meaning you can expand your collection cheaply and easily. The best way to propagate is from cuttings, and the method is the same whether your citronella is growing indoors or outdoors. 

From a mature plant, select a healthy stem with lots of foliage. Snip the stem at around three to five inches from the top, and remove most of the leaves, leaving just two or three attached to the cutting. Fill a small pot with a well-draining, nutrient-rich substrate, and gently press the snipped end of the stem into the soil.

If you want to speed up the rooting process, you can dip the end of your cutting in a small amount of rooting hormone before placing it in the soil. Place your cutting somewhere warm where it will receive a moderate amount of indirect sunlight and keep the plant and the soil lightly moist but not soggy, ideally using a spray bottle to mist it. After a few weeks, your cutting should start to produce its own healthy root system, after which you can move the cutting to its intended growing position. 

FAQs

Conclusion

Whether you’re charmed by citronella’s delicate blooms, you’re captivated by its uplifting fragrance, or you’re a foodie who’s always on the lookout for interesting ingredients, there are countless reasons to have a go at growing your own citronella plant. And happily, this forgiving flower is accessible to any gardener, no matter their expertise. It’s impossible not to be tempted by this citrusy sensation! 

Sharing is caring!