How to Care for Your Citronella Plant

Citronella (also known as the Mosquito plant, Pelargonium citrosum, and citrosa geranium), is an evergreen perennial known for its lacy leaves and lemony scent. Native to South Africa, this herbaceous shrub produces bright pink, white, or lavender flowers over the summer months, and can bloom outdoors in warmer climates like Florida or Southern California in the USA. 

While originally marketed as a mosquito repellant, as biological compounds like citronellol, geraniol, and citronellal can be found in the plant leaves and can repel mosquitos, the amounts present are so small that it would require crushing the leaves to show any effect. With that said, while citronella plants may not repel a mosquito, the plant is not pet safe, so make sure it is out of the way of cats and dogs that like to chew.

Plant parents and gardeners love these plants as they are easy-to-care for houseplants, they love sun and can tolerate light shade both indoors and outdoors, and they have adapted to drought making them perfect for beginners. So if you’re ready to help your Citronella thrive, this guide walks you through watering, sunlight, and diagnosing common health issues. 

Pelargonium citrosum is a hybrid plant whose roots can be found with the Pelargoniums living in tropical regions of Southern Africa along the Western Cape and Langeberg Mountains, growing on the sandy banks along rivers and streams. The seeds are adapted to spread through the wind, as they are lightweight and have a feathered spiral-shaped tail to help the seed drill into the soil when it lands. The bright flowers help attract bees for pollination, while its lemony scent deters local wildlife from taking a bite. 

While the plants have been on collector’s radars since the late 1700’s, it wasn’t until the 1990s that the mosquito plant became popular all over the world due to marketing. Its scent resembles the lemongrass or citronella grass (Cymbopogon nardus) allowing marketers to create a comparison and since then it has thrived as part of household nurseries and home landscapes. That’s likely why you’re seeing them at your nursery and are on this guide.

Knowing if your Citronella is the actual plant is vital to giving it proper care. Although Citronella is called a geranium, since 1789 they have been classified as a separate genus, Pelargonium, that is within the same Geraniacea family as Geraniums. 

Most geraniums on the market are actually Pelargoniums, known as scented geraniums or tender geraniums. Unlike true geraniums, Pelargoniums are not cold resistant, have a woody stem, and most flowers are asymmetrical with 5 petals and patterns. 

There are 3 Pelargonium species that are sold interchangeably as the Mosquito plant in many nurseries: Pelargonium citrosum, Pelargonium graveolens, and the cultivar Pelargonium citrosum 'Van Leenii.' Here’s how to identify yours.

Citronella Pelargoniums are easygoing plants that love sun and warm temperatures, and should be overwintered inside. With the guide below, you’ll learn how to keep your scented geranium thriving year round.

Pro-tip: Deadhead or pinch off small stems to encourage more blooms. 

If grown in a container, look for one that is at least 12 inches deep and twice as large as the root ball to give the taproots plenty of room to grow. If grown outside as part of the landscape with multiple plants, your Citronella loves their space as it helps them get enough light to all their leaves and should be given at least 12 inches of space between plants. 

Pro-tip: 5-10 days after transplanting into a new container, pinch back stems and older flowers to keep your Citronella shrub like and promote fresh growth in its new pot. You can also rotate your shrub every week to ensure all sides benefit from plenty of light and have even growth.

Water when the top 1-2 inches of potting mix feel dry, usually around every 5-6 days in the warmer months. When the top few inches feel dry when you stick your finger into the pot, give your plant a good soak and add water until it drains from the pot's drainage holes. This means the soil is thoroughly moistened and can also flush excess salts in the soil. 

Pro-tip: These scented geraniums are drought tolerant, but if you see the edges of the leaves start to turn brown it’s time to increase watering frequency as that means your mosquito plant is thirsty. 

Overwatering can cause root rot, so it is better to wait a few days until the top 1-2 inches feel dry when you stick your finger into the pot rather than stick to a strict watering schedule. The rule of thumb is you’ll water more frequently in hot, dry climates compared to cooler humid ones. Reduce watering in the fall and winter as temperatures cool and growing slows.

Pro-tip: Avoid watering with tap water; Citronella can be sensitive to the minerals found in hard tap water, and prolonged exposure can cause tip burn. Use distilled, filtered, rain, or bottled water instead. 

Citronella prefers bright direct light for at least 6-8 hours a day when grown outside, and up to 12 hours if inside. Place by a South, East, or West facing window that receives plenty of light throughout the day, or by a north facing window with hot afternoon sun filtered by a gauze curtain or shade cloth.

If your plant appears leggy or has sprawling floppy stems, it probably needs more sunlight. Move it outside or onto a windowsill or box to increase light exposure. 

Mosquito plants can be placed on an outside patio during the warm spring and summer months without needing a blind, shade, or shadow so they can get more direct light exposure. But make sure to spend a few days slowly adjusting their position outside from partial shade to full direct sunlight to help them acclimate to the change from indoors to outdoors if you take them in during the colder months. 

Plant fact: Young plants will be less tolerant of direct sunlight in the afternoons, so try to position them to receive plenty of bright morning sun instead. 

If the leaves are shriveling, wilting, or turning brown, check if the soil is too dry as you may be underwatering. If your plant wilts in the heat of the midday sun and has not recovered by evening it likely needs more water. Add water to the soil until it feels damp but not wet, and until water begins draining from the bottom of the pot. Make sure your potting mix is well draining but does retain some moisture. 

If the leaves are turning yellow, appear pale, or have started dropping, this is a sign of overwatering so reduce the watering frequency and check for bacterial or fungal growth. Your plant may also appear limp and the roots may also have turned brown or black if overwatered. Check the top few inches of your potting mix to make sure it isn’t waterlogged. Remove the discolored leaves to promote foliage growth and flower formation. 

As your Citronella matures, older leaves also naturally start to turn yellow. Once there are no more green parts of the leaf, it can be pruned to promote new growth. If it's a single leaf yellowing at a time, it’s more likely to be aging compared to the plant as a whole turning yellow. 

Yellow leaf edges can also be a sign of shock due to watering with cold water. Use room temperature water instead, especially with sensitive young plants.