Quick answer: The citronella plant you find at garden centers is a lemon-scented geranium (Pelargonium ‘Citrosa’), and it’s one of the easiest, best-smelling patio plants you can grow. It loves sun, hates wet roots, and grows into a bushy 2 to 4 foot plant in a single summer. The one thing to know before you buy is that it does not keep mosquitoes away just by sitting in a pot. The scent only comes out when you crush the leaves, and the real citronella oil comes from a completely different plant. Grow it for the fragrance and the looks, keep it out of reach of pets, and if you have a pond or patio tank, control mosquitoes in the water itself.
Citronella plant at a glance
| Detail | Citronella plant |
|---|---|
| Scientific name | Pelargonium ‘Citrosa’ (a scented geranium) |
| Other names | Mosquito plant, citrosa geranium, citronella geranium |
| Adult size | 2 to 4 feet tall and about as wide |
| Lifespan | Perennial in USDA zones 9 to 11. Grown as an annual elsewhere, or brought indoors for winter |
| Light | Full sun, at least 6 hours a day |
| Water | When the top 1 to 2 inches of soil are dry |
| Soil | Loose, well-draining potting mix |
| Pet safety | Toxic to cats, dogs and horses |
| Care level | Easy, good for beginners |
Citronella plant vs citronella grass vs lemongrass: which one do you actually have?
This is where most of the confusion starts. Three different plants get tied to the word “citronella,” and they don’t do the same job.
| Feature | Citronella plant (geranium) | Citronella grass | Lemongrass |
|---|---|---|---|
| Scientific name | Pelargonium ‘Citrosa’ | Cymbopogon nardus / C. winterianus | Cymbopogon citratus |
| Looks like | Bushy, lacy, slightly fuzzy leaves, small pink-lavender flowers | Tall clumping grass with reddish stem bases | Tall clumping grass with pale, thick stalks |
| Size | 2 to 4 ft | 5 to 6 ft | 3 to 5 ft |
| Where you’ll find it | Almost every garden center in summer | Specialty nurseries, warm climates | Nurseries and grocery stores (the stalks root easily) |
| Source of citronella oil? | No, it just smells similar | Yes, this is the real one | No, but its oil is similar |
| Main use | Fragrant patio plant | Oil production | Cooking and tea |
Here’s the honest part most plant tags leave out: the pot labeled “mosquito plant” is the geranium, and it has the weakest claim to the citronella name of the three. It was bred to smell like citronella, not to produce it. If a label just says “citronella plant,” it’s almost always the geranium, and that’s the plant this guide covers.
What it looks like and how to tell it’s the real thing
The citronella geranium has soft, deeply cut, lace-like leaves on sturdy green stems that turn woody at the base as the plant ages. In late spring and summer it puts out small pink to lavender flowers. They’re pretty, but they’re not why people buy it.
The easiest test is your nose. Gently rub a leaf between your fingers. A true citronella geranium gives off a strong lemony, citronella-candle smell right away. If you get a faint or plain “geranium” smell, you probably have an ordinary scented geranium with a hopeful label.
| Citronella geranium | Ordinary garden geranium | |
|---|---|---|
| Leaves | Lacy, deeply cut, slightly fuzzy | Rounder, often with a dark ring or zone |
| Scent when rubbed | Strong lemon and citronella | Mild, earthy or no scent |
| Flowers | Small, pale pink to lavender | Big, showy clusters in many colors |
Setting up your citronella plant
Scented geraniums come from dry, sunny ground, and they grow best when you copy that.
Pot or ground. A container is the easiest option for most people, because you can move it into the sun and bring it indoors before frost. Pick a pot with drainage holes, at least 12 inches wide for a full-size plant. In zones 9 to 11 you can plant it straight into a well-drained garden bed.
Sun. Give it at least six hours of direct sun. In very hot climates, a little afternoon shade keeps it from scorching. In too much shade it gets leggy, floppy and less fragrant.
Soil. Use a quality potting mix and add a handful of perlite if it feels heavy or holds water. The goal is soil that drains in seconds, not minutes.
Near your pond or tank. It looks great beside a backyard pond, a patio tub or a deck tank, but keep it in a pot or a raised spot. Wet pond margins and bog areas will rot its roots within weeks. Put it right beside a bench or path where you brush past it, since that’s when you’ll actually smell it.
Watering and feeding
Overwatering kills more citronella plants than anything else. Water deeply, then wait until the top inch or two of soil is dry before watering again. In a hot summer that might be every couple of days for a pot. In cool weather it could be once a week or less. Never let the pot sit in a saucer of water.
Feed it a balanced liquid fertilizer at half strength every two to four weeks in spring and summer. Too much fertilizer gives you lots of soft green growth with less scent, so go light. Stop feeding in fall and winter.
Pinch off the growing tips every few weeks while it’s young. Each pinch makes two new shoots, so you get a bushy plant instead of a tall, floppy one. The pinched tips smell great, so rub them on your hands on the way past.
Does the citronella plant repel mosquitoes?
Not on its own, and this is the thing most people buy it for. The lemony oils stay locked inside the leaves until you crush or rub them. A pot on the patio smells nice when you brush past it, but it doesn’t create a bubble that mosquitoes won’t cross.
Rubbing crushed leaves on your skin can give a small, short-lived effect. Test a small patch first, since the oils can irritate sensitive skin. For an evening outside, it’s a nice extra, not real protection.
If you have a pond or an outdoor tank, the far better approach is to stop mosquitoes where they start, in the water:
- Keep the water moving. Mosquitoes lay eggs on calm, still water. A small fountain, waterfall, air stone or pump breaks that up.
- Let your fish do the work. Goldfish, guppies and minnows all eat mosquito larvae. A pond with a few healthy fish rarely has a mosquito problem.
- Use Bti dunks in fishless water. These use a natural bacterium that only affects mosquito and black fly larvae. It’s safe for fish, plants and pets, and handy for water features, rain barrels and plant saucers.
- Leave some open water. Floating plants are great, but a solid mat covering the whole surface hides larvae from your fish.
- Empty anything that holds water. Saucers, buckets, old tires and clogged gutters breed far more mosquitoes than a healthy pond.
For a pond plant that does help, try hornwort. It’s easy, it cleans the water, and it gives fish and fry cover without choking the surface.
Is it safe for fish and pets?
Fish. A citronella plant in a pot beside your pond or tank is no risk to your fish. The oils stay in the leaves. Citronella products are a different story. Citronella oil is mildly toxic to fish, so keep tiki torches, oil lamps and candles back from the water’s edge where they can’t tip or drip in. Never spray any bug repellent over or near the water. If oil does get into a small pond or tub, move the fish to clean water, do a big water change, and run activated carbon in the filter if you have it. Keep candles and diffusers away from indoor aquariums too.
Pets. This is the real safety issue. Scented geraniums, including the citronella plant, are toxic to cats, dogs and horses. Chewing the leaves usually causes vomiting and a sore stomach, and rubbing against the plant can irritate the skin. Cats are the most sensitive. If you have pets that chew plants, keep it on a high shelf or skip it. If a pet eats some, call your vet or the ASPCA Animal Poison Control Center at (888) 426-4435.
Propagating and overwintering
Citronella plants are one of the easiest plants to multiply, which is good news, because in most of the US they won’t survive winter outdoors.
To take cuttings, snip a 4 to 6 inch stem just below a leaf joint, strip off the lower leaves, and push it into moist potting mix. Keep it in bright, indirect light and lightly damp. Roots usually form in a few weeks, and you’ll know it’s rooted when it starts putting out new leaves. Cuttings will sometimes root in a glass of water, but they rot more often that way, so soil is the safer bet.
Before your first frost, you have two options. Bring the whole plant indoors, cut it back by about a third, and keep it in your sunniest window with only occasional watering until spring. Or take a few cuttings in late summer, root them, and overwinter those small plants instead. They take up less room and often look better by spring than the old plant.
Common citronella plant problems
Yellow lower leaves. Almost always too much water. Let the soil dry out more between waterings and make sure the pot drains freely.
Tall, floppy, leggy stems. Not enough sun. Move it somewhere brighter and pinch the tips to push bushier growth.
No smell. Normal until you touch it. The scent comes out when leaves are rubbed. More sun also means stronger oils. If it still has no lemon scent when crushed, it may not be a true citronella geranium.
Black, mushy stem base. Stem or root rot from wet soil. The plant usually can’t be saved, but healthy top cuttings can. Root them in fresh, dry mix.
Sudden collapse in fall. Frost. Even one freezing night can kill it, so bring it in when nights start dropping toward 40°F.
Tiny white flies or sticky leaves. Whiteflies and aphids occasionally show up. Rinse them off with a strong spray of water. Don’t use insecticide sprays near your pond or tank.
FAQ
Does the citronella plant keep mosquitoes away?
Not by itself. The oils are inside the leaves and only come out when crushed. It’s a nice-smelling plant, but for real mosquito control around a pond, use moving water, larvae-eating fish and Bti.
Is the citronella plant the same as citronella grass?
No. The common citronella plant is a scented geranium. Citronella oil comes from citronella grass (Cymbopogon nardus and C. winterianus), a tall grass related to lemongrass.
Can I plant citronella next to my pond?
Yes, in a pot or a raised, well-drained spot. Don’t plant it in wet pond margins or bog areas, because its roots will rot.
Is citronella safe for fish?
The plant beside a pond or tank is safe. Citronella oil, candles and torches are mildly toxic to fish, so keep them away from the water.
Can a citronella plant grow in water or in an aquarium?
No. It’s a land plant that needs dry, well-drained soil. It won’t survive with its roots constantly wet or underwater.
Is the citronella plant toxic to cats and dogs?
Yes. Scented geraniums are toxic to cats, dogs and horses. Keep it out of reach of pets.
How long does a citronella plant live?
In zones 9 to 11 it can live for years outdoors. Elsewhere, it lasts one summer unless you bring it indoors or keep it going from cuttings, which can carry the same plant on for many years.