Anyone who likes Asian cooking is likely to be a fan of the lemongrass plant. With its lemony, slightly-bitter citrus flavor and aroma, it’s commonly used in food.
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But what very few realize is that it’s fairly easy to grow at home if you’re in a warm climate. Even cooler-climate gardeners can grow it outdoors during the late spring and summer. It’s easy to bring a small clump indoors for the cold months, allowing you to grow it year-round!
So let’s explore the citrusy sensation that is lemon grass. Not only is it good for food, it’s great in the landscape!
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Overview
All About Lemon Grass
If you’ve ever smelled a citrusy, lemony odor around tall clumps of sharp-edged grass, you’re in luck. Chances are that you’ve found a cymbopogon species… and it might be tasty, too!
While there’s a very wide variety of plants in the genus Cymbopogon, only a couple are lemongrass. Many varieties do have that distinctive aroma, but that doesn’t make them edible. Let’s explore the edible varieties in a bit more detail.
Which Cymbopogons Are Lemongrass?
Two species are what we choose when we opt to grow lemongrass. These two plants are very closely related, and provide a slightly-bitter lemony flavor.
Cymbopogon citratus ‘West Indian lemongrass’, ‘Lemon grass’
Far and wide, this species is the most popular for culinary use. It can grow to reach heights of up to six feet tall. Often, it will spread to reach 3-4 feet wide as well. It originates in southeastern Asia.
Like most grasses, it emerges as a dense, round clump with long, sharp-edged blades. Hidden in the base are many stems which, when the leaves are removed, are edible. A popular ornamental plant as well, lemon grass can act as a centerpiece plant or as a tall border.
Its lemony scent when sun-warmed can make for a bright and lovely aroma in your garden. Pairing this plant with other aromatic herbs may offer limited pest-repellent potential.
Cymbopogon flexuosus, ‘Malabar grass’, ‘Cochin grass’, ‘East Indian Lemon grass’
This is closely related to the West Indian variety, but is often taken for an ornamental grass. While it is not as distinct in flavor, it can be used for food as well. Its stem bases are narrower than the West Indian type, and the bulbous end smaller.
What this plant excels in is producing essential oils. Anyone who wants to distill their own lemongrass oil will find this to be perfect. The oils from this plant are used widely in culinary and skin care product use. It provides a lemony aroma or flavor to all manner of commercial goods.
Specimens of this plant have reached a height of nearly ten feet, but it averages in the six to seven foot range. Origins of this plant range from India to Thailand.
Other Closely-Related Species
Cymbopogon nardus ‘Citronella grass’
Commonly called citronella grass, this relative isn’t edible. Instead, it’s a lemony-smelling grass that’s grown for its essential oil. Harkening from the tropical regions of Asia, it’s becoming more popular in gardens.
The plant naturally acts as a very mild bug repellent while alive by producing a light citrusy scent. The oil produced from its leaves and stems is far more potent, and often in topical insect repellents.
If not kept in check, it can spread fast, often bordering on invasive. In pasture situations, it can prove to be a major problem, as cattle won’t graze on it no matter if it’s in large supply.
Caring For Your Plant
While not particularly demanding, growing lemongrass requires a few things – lots of sunlight, regular watering, and good soil. Your plants will grow to magnificent heights if you provide the right environment. Let’s discuss lemon grass care and maintenance!
Light & Temperature
Full sun, at least 6-8 hours per day, is necessary for your lemongrass plant to grow. It can tolerate partial shade if necessary, but does best in full sun conditions.
Temperature-wise, this plant’s a warm-climate plant through and through. Anything below 40 degrees is a risk of severe plant damage and possibly death. Frost greatly damages lemon grass leaves, and can kill the plant if it reaches the roots.
People in cold climates will need to bring their plant inside for the winter. It will readily grow in a pot as long as it has good lighting and consistent watering. Select a 6″ wide, healthy clump to separate and transplant for overwintering.
Water & Humidity
Don’t allow the soil around your plant to completely dry out during the growing season. Lemon grass really prefers damp soil at all times! Place about 3-4″ of mulch around your plants to help keep moisture in the soil, and keep the soil damp to the touch.
Your plants will like a little extra humidity during hot weather as well. In fact, they’re extremely tolerant of high humidity conditions. An occasional misting during dry weather will help your plant to thrive.
If your soil dries out too quickly, you may want to consider a soaker hose under the mulch layer. This slowly-seeping irrigation system helps the soil to absorb moisture well without wasting water.
Soil
Loose, fertile soil is ideal for your lemongrass plants. Be sure it’s well-draining but rich in organic material. Avoid hard-packed clay soils, as it doesn’t grow well in them.
A good blend for growing your lemon grass plant is two parts of loamy soil to one part compost. Try to use larger-particle composts to improve the drainage of your soil. You can add perlite if necessary, but the compost provides added nutrition.
Lemon grass isn’t very sensitive to soil pH. It will grow happily in multiple ranges.
Fertilizing
Fertilize your plants weekly. Use a half-strength solution of a nitrogen-rich, water-soluble fertilizer. Don’t apply the liquid fertilizer directly to the leaves of your plant. Instead, water around the base of the plant.
This fertilization should be done throughout the summer and early fall months. June through September is recommended, as that’s when the plant’s actively growing. These regular fertilizing sessions will keep your plant healthy through the hot season.
If you don’t have a water-soluble fertilizer that will work, aim for a slow-release granular formula. Balanced will work, but ideally an 8-6-6 would be perfect. This gives a little extra nitrogen to the plant to aid in stalk development.
Propagation
Generally, lemon grass plants are propagated from seed or by division. Let’s talk about these methods in more detail.
When you have a large plant, you can consider dividing it into smaller clumps. This allows your plant to have more room to continue growing, ensuring larger plants.
To do this, carefully remove the entire plant from the soil, being sure not to damage the roots. Dust off excess soil, then tease apart clumps of stems and bulbs. You may need to use a sanitized knife to cut apart tangled roots. Replant the smaller sections and allow them to get established again. Most people opt to divide into 6″ clumps of stems and leaves.
From seed, plants take up to 14 days to germinate. You can begin harvesting individual stalks after roughly 90 days. It’s often better to allow a plant up to 120 days, if only so it can begin to expand.
Sow seeds in moistened potting soil, just deep enough to cover the seed. Keep in a warm location, using a seedling heating mat if necessary. Once the plant has germinated, ensure it has a grow lamp or other consistent light for at least 8 hours a day.
Pruning & Harvesting
Pruning is actually an ongoing process for lemongrass. You will want to rake any dead material away from the bottom of your plants. Dead stalks should be removed entirely when seen.
Damaged leaves can also be pruned at any time with a clean pair of pruning shears. Be careful, as the leaf edges can be quite sharp! Wear a sturdy pair of work gloves when handling this plant.
In the early spring, before it begins active growth, a heavy trimming should occur. Trim the entire plant back to a couple inches above the white part of the stalk. Overwintered outdoor plants are especially in need of this trimming. Any leaves which have winter chill damage will be removed then.
To harvest your lemongrass for culinary use, look closely at the plant. Select a healthy, thick stem, and carefully pull back the soil to expose the bulb-like end. Using a sharp knife, cut the stalk off just beneath its bulb to remove the entire stalk. Be sure to get the entire bulb, and if a few roots come up with it, it won’t harm the plant.
Culinary Lemongrass Storage
To store freshly-harvested culinary lemongrass, begin by peeling off the fibrous outer layers. Expose the white, reed-like inner stem and bulb. This is the part you will be saving — while the leaves have flavor, they’re best used while presh.
Lay the lemongrass stems on a cookie sheet and freeze until solid. Transfer into a plastic storage bag. Before using, thaw them. Use the flat of your knife to crush the stem and bulb before chopping them up.
Problems
Most of your problems will stem from discoloration. This can be caused by care issues, diseases, and occasionally pests. Very few of these will be fatal to your plant. Here’s a short list of what to watch out for and treatment options in case one of these problems arises.
Growing Problems
Multiple things can cause your lemon grass leaves to change color. If it’s underwatered, leaves may begin to yellow or brown. Underfertilization during the active growing season may also cause this. If this occurs during spring/summer, water more consistently and fertilize regularly.
In zones 8a-9, lemongrass may also turn reddish or brown in the fall. This is a sign of the plant entering winter dormancy. People in these zones should mulch heavily to keep the roots warm during the cool season. Alternately, a clump of lemongrass can be dug up and replanted in a pot to overwinter indoors.
People in climates that are colder than zone 8a should plan on bringing theirs indoors. This plant is susceptible to massive cold damage and plant death in cold weather.
Pests
For those who grow their lemongrass indoors, spider mites can become a problem. More accurately, they can become a major damaging pest to your plant’s leaves. Use neem oil or a mite spray to wipe these out.
The yellow sugarcane aphid and a few other types of aphids can suck the sap out of lemongrass leaves. Fine yellow spots often appear on the leaves. Aphids can also spread plant diseases, so it’s important to wipe these out quickly! Neem oil or an insecticidal soap will get rid of these pests.
Finally, the grass bagworm is a minor problem in some regions. While it does not kill its host plant, it can eat unattractive holes into the long, sharp leaves. This bagworm is actually a moth larvae, and a spray or dust of bacillus thurigiensis kills them off.
Diseases
A specific type of rust, Puccinia nakanishikii, has been known to attack these plants. It can be difficult to control once established, so it’s best to avoid it entirely. Don’t wet the leaves of your plant while watering, instead watering at the plant’s base. If you find symptoms, opt for a liquid copper fungicide or a biofungicide to clear it up. Remove any damaged leaves which show signs of the rust so it doesn’t continue to spread.
Leaf blight caused by rhizoctonia solani is not uncommon. This same pathogen can cause root rot as well. Leaves may develop yellow splotches. Root and stem damage is visible as brown lesions near the soil’s surface. Plants may wilt in hotter weather. This fungal disease can remain in the soil for years. Some forms of bacteria, mostly Trichoderma species, can slow its development. Use an inoculant in the soil when planting. Also apply a water-soluble inoculant at least once early in the growing season.
Two fusarium strains cause leaf spot & clump rot in lemongrass. Fusarium equisetti and fusarium verticillium are common and impact many types of plants. Mycorrhizal and bacterial treatment is the most common form of protection against fusarium. Like rhizoctonia, fusarium fungi can live in the soil for a long time.
Frequently Asked Questions
Q: Is lemongrass an annual or a perennial?
A: In zones 10 & 11, Cymbopogon citratus will remain green year-round. It’s a perfect perennial in these environments which mimic its native range.
In zones 8a-9, you can manage to grow lemongrass as a perennial. The foliage may die back and turn brown. As long as the root structure is protected, it should recover in the spring.
Most other regions grow lemongrass outdoors as an annual or seasonal plant. When cooler weather arrives, a clump is brought indoors to overwinter in warmer temperatures.
Q: Is lemongrass safe around dogs and cats?
A: In dogs and cats, Cymbopogon citratus is known to cause stomach upset. It generally will not kill them, but they won’t be happy. The fibrous stalks can also cause intestinal problems if consumed. Horses are at higher risk, as they can develop breathing issues and weakness from this plant. Keep your equine friends away from lemongrass!
Q: Does lemon grass repel mosquitos?
A: Cymbopogon nardus, the Citronella grass, produces three oily compounds which are believed to repel mosquitoes (citronellol, citronellal, and geraniol). In limited quantities, other lemongrass varieties may also contain citronellol. Unfortunately for us, these only work in close range. You know how you get chased by mosquitoes when you move out of the range of your citronella candle? The plants have a similar localized effect. Growing citronella plant or lemongrass in your yard may reduce its likelihood to be colonized by mosquitoes, but will not necessarily repel them from your yard entirely. The area nearest to the sun-warmed plants may experience fewer mosquitoes than other parts.
The oils from citronella grass can be distilled and used to create insect repellents for topical use. As an oil, it’s far more potent and effective.
Both ornamental gardeners and edible gardeners will love their lemon grass. It isn’t a flowering plant, but it provides great visual appeal in the landscape. Plus, that lovely aroma and good flavor make it worth growing even if you just want it to cook with. So consider growing your own lemongrass next season. You’ll be glad you did!
