Grass (Poaceae family) is a curious thing – on the one hand, it’s a weed that some people love and some hate. On the other hand, some types of grass are edible or even beneficial.
Take, for example, Cymbopogon nardus (sim-buh-POH-gon NARD-us), a perennial plant from Sri Lanka that’s become one of the most important sources of citronella oil.
This is where this plant gets its common name of citronella grass, although it’s also sometimes referred to as Ceylon citronella.
Note that this common name sometimes refers to the entire genus, but this species is the one most people refer to when talking about citronella grass.
Citronella Grass Care
Size and Growth
This fast-growing grass can reach a height of up to 6’ feet and a clump size of around 4’ feet across.
Its long, lanceolate leaves give off a citrus scenery when bruised or crushed.
Flowering and Fragrance
While not common indoors, citronella grass may bear flowers from summer into fall.
These are usually a light brown to pink coloration and are somewhat unremarkable in size.
Light and Temperature
While your lawn may love lots of direct sun, citronella grass is a bit more sensitive and can scorch in the midday sunlight.
Try planting it with full exposure to the east or west but some partial shade at midday. Dappled sunlight is also an excellent option.
If growing indoors, an eastern or western window where it can get at least 6 hours of direct light or 8 hours of filtered light will work great.
However, be sure to use a sheer curtain or avoid putting it directly in a southern window.
A moderate humidity level is perfect for this plant, ranging from 40% to 70% percent.
Avoid anything higher, as this can lead to fungal infections, and note that it will need more frequent watering in arid conditions.
Citronella grass is generally grown outdoors in USDA hardiness zones 10 to 12, although it can actually handle a wide temperature range.
Brief exposures down to 32° degrees Fahrenheit won’t cause serious harm, but prolonged exposure or temperatures lower than this can harm or even kill the plant.
At the other end of the spectrum, it can tolerate up to 90° degrees Fahrenheit but may scorch or dry out at higher temperatures.
North of zone 10, many people like to grow this grass as an annual.
It can also be cut back to 3” inches and brought inside to a sunny window or placed under grow lamps to keep it thriving throughout the winter.
Watering and Feeding
Citronella grass likes moist soil, but that doesn’t mean you have to drown it.
Instead, wait to water the plant until the top 2 to 3” inches of soil is dry.
You can test this by sticking your finger straight down into the ground, as each knuckle is approximately 1” inch from the next.
Keep in mind this plant may need to be watered as often as daily or as little as once per week, depending on how much direct sunlight the grass receives or how humid its environment is.
This is why you don’t want to water on a schedule.
When watering, the soak and dry method work very well for this plant in both a container or the ground.
Avoid using overhead watering to reduce the risk of fungal infections. This is a very forgiving grass and only needs to be fed once in the spring.
As with most grasses, a high-nitrogen mix works best, and you can generally use the same fertilizers you would use on your lawn.
Soil and Transplanting
While some grasses can grow in almost any soil type, citronella grass needs something more loose, such as sandy or loamy soils.
It also prefers a surprisingly acidic soil pH of 5.8 to 6.0, which means it may not be compatible with many other garden plants.
This can be mitigated by creating a barrier around the plant at least a foot deep so the soil inside and outside of the barrier won’t mix.
Peat moss, perlite or vermiculite, and sulfur are all good things to add to maintain proper drainage and pH levels.
While many people further south will want to grow citronella grass in their yard or garden, those further north (and some in the south) may wish to grow this plant in pots.
While this can make it possible to grow the plant in cooler climates or on patios, it does mean you will need to repot them every once in a while.
You’ll want a fairly large container to start, with a gallon being a great starter size.
When you see the plant has run out of room to spread, it’s time to give it a new container a size larger.
You will also want to repot every 2 to 3 years to ensure it has fresh soil.
Remember, grass can be fragile, so while using a trowel to loosen the soil around the pot’s edges, you don’t want to pull at the grass itself. Instead, tip the pot and gently slide the grass out.
Grooming and Maintenance
As this is a type of grass, there’s very little need for any type of maintenance.
If you’re growing indoors (or there are local ordinances that affect ornamental grass size), you can trim the blades down to shape or a desired size without harming the plant.
How To Propagate Cymbopogon Nardus
As with most grasses, division and seeds are the two easiest ways to propagate this plant.
However, some have also reported success using stem cuttings.
Citronella Grass Pests Or Diseases
While somewhat sensitive to too much direct sunlight, not much will harm this plant.
In fact, your biggest problems are water related, such as root rot, fungus gnats, or fungal infections.
However, you should be aware that this grass is considered mildly toxic to humans and pets.
While not life-threatening, consuming this grass can cause several uncomfortable symptoms, including:
- Hypothermia-like symptoms
- Lack of muscle coordination
- Muscle weakness
Note also that some people may have a skin sensitivity or allergy to citronella grass, although this isn’t very common.
Cymbopogon Nardus Uses
One of the most obvious uses of this plant is to repel mosquitoes and several other pests.
The essential oil is extracted for several commercial uses, such as citronella candles.
You can also break off leaves and rub them on your skin for some instant bug repellent.
When potted, this plant makes a lovely accent for patios and decks and can be brought inside for the winter in cold climates.