Mosquito-repelling plants for the balcony: Citronella and scented geraniums

By planting your balcony thoughtfully, you can prevent precisely that situation.

Many people instinctively reach for chemical sprays or light scented coils that smell more like a campsite than a holiday retreat. Yet a few carefully selected herbs and fragrant plants can create a kind of natural scent barrier that confuses mosquitoes while turning the entire balcony into a pleasantly scented miniature garden.

How plants outsmart mosquitoes: the science behind it

Mosquitoes do not find us by chance. They rely primarily on two signals: the carbon dioxide we exhale and our body odours. This is exactly where certain aromatic plants come in.

Their leaves and stems contain essential oils that are released into the air and thoroughly disrupt mosquitoes’ “smell sensors”.

These fragrances form a veil over the scent signals produced by people and pets, making it far more difficult for mosquitoes to locate a source of blood. A 2023 study by the French research institute INRAE found that correctly positioned plants can reduce the number of mosquitoes in an area by up to 45 per cent. This is not mysticism, but a measurable effect.

Scented geraniums rather than decoration: the true balcony guardians

When people hear “geranium”, they often picture the familiar red balcony flowers hanging in window boxes everywhere. They may look attractive, but they do little to deter mosquitoes. It becomes interesting only with scented geraniums, particularly the variety often sold as a rose geranium (botanically Pelargonium graveolens).

Its leaves contain large amounts of essential oils. Brush your hand across them or snap a leaf, and the plant releases an intense fragrance with notes of rose and citrus. Mosquitoes strongly dislike this aroma and keep their distance.

A strongly scented rose geranium placed directly on a windowsill can act like an invisible curtain, allowing noticeably fewer mosquitoes into the home.

In practical terms, rose geraniums should be placed as close to doors and windows as possible, ideally in planters that “guard” the transition between the home and the balcony.

Citronella: a classic with an immediate effect

The second major classic among mosquito deterrents is the citronella plant, a tropical sweetgrass. Many people know the name from candles or coils, but the living plant is the more powerful option.

Its long, narrow leaves are packed with lemon-scented compounds. These interfere with insects’ nervous systems, encouraging them to keep their distance. In the UK climate, citronella needs a warm, sheltered position and is usually grown in a pot on the balcony.

• Position: sunny and protected from the wind
• Container: a fairly large pot, as it can grow vigorously
• Placement: as close as possible to the seating area or balcony door

Pairing citronella with scented geraniums creates a strong first line of defence that is both visually appealing and intensely fragrant.

Edible and effective: lemon basil and peppermint

Lemon basil: protection and summer flavour in one

Lemon basil is still something of an insider tip in the UK. Unlike the classic basil used for pesto, this variety has a pronounced citrus scent. That is precisely what mosquitoes dislike.

It also has a practical advantage: its leaves enhance salads, fish dishes and fruit bowls, and work beautifully in homemade lemonade. Place the pot close to the balcony railing or beside a sun lounger for protection as well as fresh seasoning within easy reach.

Peppermint: powerful fragrance, vigorous roots

Peppermint is exceptionally hardy and rich in menthol, the compound responsible for its distinctive cool mint scent. Mosquitoes are sensitive to it.

Peppermint is ideal for beginners, but it needs to be kept under control because its roots can quickly take over an entire planter.

The solution is to keep peppermint in its own pot, then place that pot inside a larger container or balcony planter. This keeps it manageable and allows you to position it specifically in “problem areas”, such as beside a small table or at the head of a sun lounger.

The perfect plant mix for a balcony planter

The effect becomes particularly strong when several of these plants work together as one system. Their different scents overlap, saturating the air more evenly with active compounds.

The more different fragrance sources there are in a small space, the denser the “scent curtain” mosquitoes have to pass through.

A combination for a longer balcony planter could look like this:

• Two rose geraniums as strongly scented “end posts” at either side
• One citronella plant in the centre as a tall focal point