Lemongrass and citronella grass are two different plants.
They’re close cousins in the same grass family, and the confusion gets worse because a third plant, a lemon-scented geranium, is also sold as “citronella.” If you want a plant to cook with, grow lemongrass (Cymbopogon citratus), because it’s the type sold for food, while citronella grass is grown for its oil and the citronella geranium is a scented patio plant.
None of the three will keep mosquitoes off your deck just by sitting in a pot.
Once you know which plant is which, you can pick the right one for your kitchen, your patio, and your pets, and you’ll avoid paying for a mislabeled pot at the garden center.
Which Plant Should You Grow? The Short Verdict
For most American home gardeners, I’d grow lemongrass. It gives you fresh stalks for soups, curries, and tea. It also has a bright citrus smell and makes a handsome fountain of leaves on a patio. If you are stocking up, a lemongrass plant is the first thing I would pick up.
Citronella grass makes sense if you want a big, bold ornamental grass and you like its sharper scent. Keep it out of the kitchen. It’s raised mainly as an oil crop.
The citronella plant, a scented geranium, is the easiest of the three to tuck into a small pot. It’s a pretty, lacy-leaved plant with a lemony smell when you rub the leaves. It isn’t a grass at all.
My simple rule for choosing between citronella and lemongrass:
- You want to cook with it: lemongrass.
- You want a tall, dramatic grass for a big container or warm-climate bed: citronella grass.
- You want a compact, fragrant pot plant for a table or railing: the citronella plant (scented geranium).
If you only have room for one, lemongrass gives you the most uses from a single pot.
Three Plants at a Glance
The three plants differ in family, edibility, and size, and the table below lays it out side by side. Lemongrass and citronella grass both belong to the genus Cymbopogon, a group of oil-rich tropical grasses. The citronella plant belongs to the geranium family.
| Lemongrass | Citronella grass | Citronella plant | |
|---|---|---|---|
| Botanical name | Cymbopogon citratus | C. nardus (Ceylon) or C. winterianus (Java) | Pelargonium ‘Citrosa’ |
| Plant type | Tropical grass | Tropical grass | Scented geranium |
| Stalk base | Pale green to white | Reddish to purple | Soft, branching stems |
| Grown for food | Yes | No | No |
| Typical height | 2 to 4 feet | 4 to 6 feet | 1 to 3 feet |
| ASPCA pet listing | Toxic to cats, dogs, horses | Not separately listed | Geraniums toxic to pets |
A few names on plant tags cause trouble:
- West Indian lemongrass (Cymbopogon citratus) is the cooking type you find in grocery stores.
- Ceylon citronella (Cymbopogon nardus) and Java citronella (Cymbopogon winterianus) are the two main citronella grasses. Both are grown to distill citronella oil.
- Citronella geranium, also sold as the mosquito plant, is a scented-leaf Pelargonium bred for its lemon smell.
How Can You Tell the Grasses Apart?
You’ll spot the difference fastest at the base of the stalks, where citronella grass turns reddish and lemongrass stays pale green. Leaf size, clump height, and scent add more clues, though smell alone can fool you.
Check the Stalk Base and Its Color
Pull the leaves back and look at where the stalks meet the soil. Lemongrass has thick, pale green to creamy white bases that look a bit like green onions. Those plump bases are the part you cook with.
Citronella grass has thinner bases with a reddish to purplish blush. That color difference is the single best field test for citronella grass vs. lemongrass.
One catch: lemongrass sometimes turns purple too, from cold nights or a lack of phosphorus. If your plant is changing color, read up on lemongrass turning purple or red before you assume it’s mislabeled.
Stress coloring usually shows up on the leaves, while citronella’s red sits at the stalk base.
Compare Leaf Shape and Growth Habit
Lemongrass forms a tight clump of arching, blue-green leaves about 2 to 4 feet tall. The leaves are narrow and slightly rough, with edges sharp enough to nick bare skin, so wear gloves when you trim.
Citronella grass grows bigger and looser. Mature clumps reach 4 to 6 feet in warm climates, and the leaves are longer and floppier. Its leaf edges are also sharp.
The citronella geranium looks nothing like either one. It has soft, deeply cut, slightly fuzzy leaves on branching stems, and it may produce small lavender-pink flowers.
Use Scent as a Clue, Not Proof
Crush a leaf between your fingers. Lemongrass smells clean and lemony, like lemon candy, because its oil is rich in citral. Citronella grass smells sharper and more medicinal, close to a citronella candle.
Treat smell as a hint only. Scent strength changes with weather, plant age, and the variety, and after a few sniffs your nose gets tired. Check the stalk color and the tag before you trust your nose.
Which One Can You Eat?
Lemongrass is the one to eat, and citronella grass should stay in the garden. The geranium version isn’t a food plant either.
Why Culinary Lemongrass Belongs in Food
Cymbopogon citratus is the lemongrass sold in grocery stores and used across Thai, Vietnamese, and Caribbean cooking. You use the tender lower 4 to 6 inches of the stalk, bruised or sliced thin, plus the leaves for tea.
Lemongrass oil is also on the FDA’s list of substances generally recognized as safe in food.
When your clump has stalks about half an inch thick, it’s ready to harvest lemongrass by snapping or cutting stalks at the base. For more on which parts are tender and how to prep them, see can you eat lemongrass.
Why You Shouldn’t Substitute Citronella Grass
Citronella grass is grown for oil, so it isn’t bred for flavor or tenderness. Its stalks are thin and woody, and the taste is harsh and soapy.
A few cooks in other parts of the world use it as a flavoring, but there’s no good reason to swap it in when real lemongrass is cheap.
The citronella geranium is even less suited to food. Scented geraniums can irritate skin, and this one isn’t sold as an edible herb. If a pot isn’t clearly labeled Cymbopogon citratus, I’d keep it out of your cooking.
Will Either Plant Keep Mosquitoes Away?
No living plant, lemongrass or citronella, will protect you from mosquito bites just by growing nearby. The repelling compounds are locked inside the leaves and only release in small amounts when you crush them.
Living Plants vs. Citronella Oil
Citronella oil is distilled from citronella grass, and it does repel mosquitoes for a short time. The trouble is that it evaporates fast. Lab studies show protection fading in under an hour, much faster than standard repellents.
A plant in a pot gives off far less scent than the concentrated oil. Brushing the leaves releases a little, but that cloud drifts off within minutes.
The same goes for lemongrass, whose citral-rich oil has some repellent action only in concentrated form. If you want the full details on that plant, my article on does lemongrass repel mosquitoes covers it.
Please don’t rub crushed leaves or undiluted essential oils on your skin. Pure oils can cause burns, rashes, and allergic reactions.
What to Use When You Need Reliable Protection
For real protection on summer evenings, use an EPA-registered repellent. My pick for people who prefer a plant-based product is an EPA-registered lemon eucalyptus repellent, made with oil of lemon eucalyptus (OLE).
It’s a different product from household lemon eucalyptus essential oil. Don’t use OLE products on children under 3.
These steps also help:
- Dump standing water from saucers, buckets, and birdbaths every 5 to 7 days.
- Run a box fan on the patio, since mosquitoes are weak fliers.
- Wear loose, light-colored long sleeves at dusk.
Keep your live lemongrass plants for their scent and the kitchen, and count on the repellent for bites.
How Do Their Growing Needs Compare?
Both grasses love heat, full sun, and steady moisture, while the citronella geranium prefers slightly drier soil and some afternoon shade in hot regions. None of the three survives frost outdoors.
Sun, Soil, Water, and Summer Feeding
Sun: Lemongrass and citronella grass need at least 6 hours of direct sun a day, and more is better. If you’re unsure your spot qualifies, check how much sun lemongrass needs.
The citronella geranium also wants 6 hours, but in the Southeast and Southwest it does better with afternoon shade.
Soil: Give the grasses rich, loamy soil that holds moisture yet drains well. The geranium prefers a lighter, sandier mix and slightly acidic soil.
Water: The grasses are thirsty. Keep the soil evenly moist, watering when the top inch dries, which can mean daily for pots in July. Water the geranium less often and let the surface dry between drinks, since soggy soil causes root rot.
Feeding: Feed lemongrass every 2 to 3 weeks in summer with a nitrogen-rich or balanced fertilizer. Citronella grass likes the same. Young geraniums need a balanced liquid feed every few weeks, and mature ones need little.
USDA Zones and When to Move Pots Indoors
All three are tropical. Lemongrass is hardy only in USDA zones 10 to 11, and in zone 9 it can survive with mulch and protection. Citronella grass and the citronella geranium have similar limits.
In the Northeast, Midwest, and Pacific Northwest, treat them as summer plants. Set lemongrass outside once nights stay above 60°F, and bring pots indoors before nights drop below 50°F. Curious about overwintering? See does lemongrass come back every year.
Before moving a grass indoors, cut it back to about 6 inches and set it in your sunniest south-facing window.
Starting Plants and Keeping Them Healthy
The cheapest way to start lemongrass is from grocery store stalks. Pick firm stalks with the base intact, set them in an inch of water, and pot them up once roots reach about an inch long. Here’s my guide to regrow lemongrass from store-bought stalks.
Citronella grass is best bought as a nursery division. The geranium roots easily from 4-inch stem cuttings.
Watch for these common problems:
- Brown, dry leaf tips: underwatering or low humidity.
- Yellow, limp leaves: soggy soil or a pot without drainage holes.
- Rusty streaks on grass leaves: rust fungus, so water at soil level.
- Aphids or whiteflies on geraniums: knock them off with a strong spray of water.
If your grass is fading anyway, my article on why a lemongrass plant is dying walks through the fixes.
Are These Plants Safe Around Pets?
None of these three is a safe snack for pets, and the ASPCA lists both lemongrass and geraniums as toxic. Most cases cause stomach upset, not life-threatening poisoning.
What the ASPCA Says About Lemongrass and Scented Geraniums
The ASPCA lists lemon grass as toxic to cats, dogs, and horses. Eating it can cause vomiting and diarrhea, and large amounts of the tough leaves can cause a blockage in the gut.
The ASPCA also lists geraniums (Pelargonium) as toxic to cats and dogs. Signs include vomiting, poor appetite, depression, and skin irritation. That covers the citronella geranium.
Concentrated citronella oil and lemongrass oil are a bigger risk than the plants, especially for cats, so keep candles and diffuser oils away from pets. For more detail, read is lemongrass safe for pets.<