The lemongrass plant looks like an ordinary clump of grass until you brush against it and that bright citrus scent fills the air. Native to the warm, humid corners of South and Southeast Asia, this tender perennial (Cymbopogon citratus) earns its keep two ways: as a striking 3-to-5-foot ornamental grass that sways in the summer breeze, and as the lemony backbone of Thai, Vietnamese, and Cambodian cooking. The good news for home gardeners is that it is genuinely easy to grow, even in a pot on a sunny patio, and you can start a whole stand from a single grocery-store stalk. Here is everything you need to plant, grow, troubleshoot, harvest, and use lemongrass.
Lemongrass Is a Tender Tropical Grass, Not a True Herb
Despite its place in the herb garden, lemongrass is a grass in the Poaceae family. The genus Cymbopogon holds more than fifty species, but only a couple are what cooks mean by “lemongrass.” Knowing which one you have matters, because their flavor and uses differ.
Cymbopogon citratus, or West Indian lemongrass, is the one to grow for the kitchen. It forms a dense round clump of long, sharp-edged blades and can reach 3 to 6 feet tall and 3 to 4 feet wide. The swollen white stem bases hidden at the bottom of the clump are the prized edible part. Cymbopogon flexuosus, East Indian or Malabar grass, is taller and narrower with smaller bulbs; it is grown mostly for its essential oil and is milder on the plate. A third relative, Cymbopogon nardus or citronella grass, is the source of citronella oil but is not edible, so do not confuse it with the culinary types when buying plants.
All of them share the same tropical temperament. Lemongrass is perennial only in USDA zones 10 and 11, where it stays evergreen year-round. In zones 8a through 9 it dies back to the ground in winter and returns in spring if the roots are protected. Anywhere colder, treat it as an annual or grow it in a container you can move indoors. Frost damages the leaves and a hard freeze below 40 degrees Fahrenheit can kill the plant outright.
Give Lemongrass Full Sun, Rich Soil, and a Warm Start
Lemongrass loves heat, so site it in the sunniest spot you have. It wants 6 to 8 hours of direct sun a day; plants grown in shade stay sparse, leggy, and more prone to pests. Even in hot Southern gardens it thrives in full sun.
The soil should be rich, loamy, and well-draining but able to hold moisture. Before planting, work several inches of aged compost or composted manure into the bed to feed the plant and improve water retention. Lemongrass is not fussy about pH, but it does best in the slightly acidic to neutral range of about 6.0 to 7.0. A good container blend is roughly two parts loamy potting mix to one part compost, with a handful of perlite if drainage is poor.
Timing is the part beginners get wrong. Because lemongrass is so frost-sensitive, set out plants only after all danger of frost has passed and nighttime temperatures hold steady around 50 degrees Fahrenheit. In most of the country that means late spring. If you are adding several plants to a bed, space them about 24 inches apart so each clump has room to fill out and air can move between them.
Grow Lemongrass in a Pot If You Garden Anywhere Cold
For the majority of gardeners north of zone 9, a container is the smartest way to grow lemongrass, because you can carry the plant indoors before frost and keep it going for years.
Choose a pot at least 12 inches across, or a 5-gallon bucket with drainage holes, and use a quality potting mix enriched with compost. A bigger pot is better than a small one: lemongrass grows tall and top-heavy, and a mature clump can tip a light pot over in wind, so set containers in a slightly sheltered spot. Roots are vigorous and can quickly fill, and even split, an undersized pot, so plan to step the plant up or divide it every year or two. Refreshing the potting soil each spring also replenishes nutrients the previous season’s growth used up.
Water Consistently and Feed for Lush Growth
Lemongrass comes from regions of regular rainfall and high humidity, so it wants steady moisture. Keep the soil damp to the touch and never let the roots dry out completely during the growing season. The standard inch of water per week works as a baseline, but in heat and especially in containers you will likely water more. A 3-to-4-inch layer of mulch around in-ground plants conserves moisture, smothers weeds, and feeds the soil as it breaks down. That said, lemongrass becomes fairly drought-tolerant once well established, so it forgives the occasional missed watering better than it forgives soggy, waterlogged roots.
This grass is a heavy feeder, particularly of nitrogen, which fuels the leafy, stalky growth you are after. During the active season from late spring through early fall, feed every couple of weeks with a water-soluble fertilizer, or use a nitrogen-leaning slow-release granular formula such as a 6-4-0 or 8-6-6 at the start of the season. Water it in around the base rather than over the leaves. Plants that go hungry signal it with pale, yellowing, or browning foliage.
Start New Plants from a Grocery-Store Stalk, Seed, or Division
One of the most satisfying things about lemongrass is how easily it multiplies. There are three reliable routes.
Rooting stalks in water is the cheapest and most popular method, and it has a very high success rate. Buy fresh stalks from an Asian grocery or a well-stocked supermarket and pick the ones with as much of the bulbous base intact as possible; a few existing roots are a bonus. Stand them bulb-down in a jar with about an inch of water and set it on a bright windowsill. Change the water every day or two to keep fungus at bay. Over about three weeks the tops push out new leaves and the bases sprout roots; once those roots are 1 to 3 inches long and side shoots appear, pot the rooted stalks up in rich soil.
Division is the fastest way to bulk up plants you already have. In early spring, lift a mature clump, knock off excess soil, and tease or cut it apart with a clean knife into sections of at least five or six bulbs each. Replant the divisions immediately, water well, and keep them moist while they re-establish. Because lemongrass forms a dense, woody crown, a sharp spade or hatchet is often needed to slice through it like a pie.
Growing from seed works too, though seed can be hard to find. Press seed lightly into warm, moist potting mix; it germinates in roughly 7 to 14 days with a high success rate. Thin or transplant seedlings to stand about a foot apart when they reach 6 inches tall, and plan on about 90 days from germination before the first harvest.
Harvest the White Stalk Bases as Soon as Plants Are a Foot Tall
You can begin harvesting once a plant is about 12 inches tall and the stem bases are at least half an inch thick across. Harvesting is different from pruning: rather than shearing the top, you take whole stalks from the outside of the clump, leaving the younger inner stalks to keep growing. A healthy mature clump can yield a small harvest every two to three weeks during active growth.
To harvest, grasp a thick outer stalk near the base and pull, or cut it off at ground level with a sharp knife just below the bulb. You want the entire swollen white base, which looks like a fat green onion; if a few roots come along, it will not hurt the plant. The grassy upper leaves can be razor-sharp, so wear gloves and trim the tops off carefully.
The tender white inner stalk is the part most recipes call for. Peel away the tough fibrous outer layers to expose the soft, pale heart, then bruise it with the flat of a knife to release the oils before slicing or mincing. The fibrous green leaves are too tough to eat but make an excellent steeped tea or a flavoring for broth and marinades. To store the stalks, freeze them whole or chopped in a sealed bag; to keep the leaves, bundle and hang them upside down in a dark place, then store dried in a sealed jar, where they hold their flavor for up to a year.
Cook With the Stalks and Steep the Leaves for Tea
Lemongrass tastes of clean, bright lemon with a faint hint of ginger and none of the bitterness of citrus rind, which is why it anchors so much Southeast Asian cooking. In the kitchen, trim off the base and outer leaves and use the yellow-white stalk: cut it into 2-to-3-inch pieces, bruise them, and drop them whole into curries, soups, and stews to infuse the broth, then fish them out before serving. For stir-fries, salads, and sauces, finely mince the tender heart so it can be eaten directly.
Beyond the stove, the leaves steep into a soothing citrus tea, and the plant’s essential oil is widely used in aromatherapy and cosmetics for its fragrance. Leftover trimmings need not go to waste: tossed on the compost pile or scattered along a patio edge, the aromatic foliage adds a fresh lemon note to the garden.
Watch for Spider Mites, Aphids, and Rust
For all its toughness, lemongrass does run into a few problems, most of which show up first as discolored leaves. Reading the color is the fastest way to diagnose what is wrong.
Yellowing leaves, especially when the soil is wet and stem bases feel soft or mushy, usually point to overwatering; let the plant dry out and ease off the watering schedule. Browning leaves more often signal the opposite, too little water or too little nitrogen, so during the growing season water more consistently and feed regularly. In zones 8a through 9, leaves turning reddish or brown in fall is not a problem at all but the natural sign of winter dormancy; mulch heavily over the crown to insulate the roots until spring.
Pests are uncommon, partly because the plant’s own aromatic oils deter many insects, but a few do bite. Spider mites are the main nuisance on plants overwintering indoors, leaving fine speckling and webbing; aphids suck sap and cause yellow spots and wilting; and the grass bagworm, a moth larva, can chew unsightly holes in the leaves. Knock back mites and aphids with neem oil or insecticidal soap, and treat bagworms with Bacillus thuringiensis.
The disease to know is rust, caused by the fungus Puccinia nakanishikii, first reported in Hawaii in 1985. It shows as light yellow spots on the leaves with brown streaks and dark pustules on the undersides, and severe cases can kill the plant. Rust spreads by wind and splashing water in warm, wet, crowded conditions, so prevent it by spacing plants properly, watering at the soil line instead of overhead, removing infected leaves, and keeping plants well fed. Leaf blight from Rhizoctonia and leaf spot or clump rot from Fusarium are less common but follow the same playbook: improve airflow, water at the base, and remove affected tissue.
Overwinter Lemongrass Indoors to Keep It Year After Year
In zones 10 and 11 lemongrass simply stays put and stays green. Everywhere colder, you have to bring it under cover before the first frost, ideally when nighttime lows start dropping toward 50 degrees Fahrenheit, since the plant is severely damaged below 40 degrees.
The simplest approach is to dig up a few stalks or a 6-inch clump, trim the foliage back to a few inches, pot them, and set them in a bright, south-facing window. Water just enough to keep the soil barely moist, because growth slows to a crawl over winter. A second option suits gardeners short on window space: cut a potted plant down hard and store it dormant in a cool, dark spot such as a basement, watering only a few times all winter to keep the roots alive. Either way, in early spring trim the clump back to about 6 inches, move it into bright warmth, resume normal watering, and the plant will rebound quickly once temperatures climb above 40 degrees.
A Word on Mosquitoes, Pets, and Companion Plants
Lemongrass is often sold as a mosquito-repelling plant, and the claim is only half true. The plant does contain small amounts of citronellol, the compound that makes citronella grass (a different species) repel mosquitoes, but those oils only work at very close range and only when released, not while the plant simply sits in the ground. Growing it near a seating area may modestly reduce mosquitoes in that immediate zone, but it will not clear your whole yard. Paired with other aromatic herbs like basil, mint, and rosemary, lemongrass can offer limited help keeping some pests off neighboring plants, which makes it a reasonable companion as well as a handsome border or centerpiece in an edible landscape.
One caution for animal lovers: lemongrass contains oils that can upset the stomachs of dogs and cats, and the fibrous stalks may cause digestive trouble if eaten in quantity. Horses are at greater risk and should be kept away from it entirely. Site the plant where curious pets are unlikely to graze on it, and enjoy it for what it does best, perfuming the garden and the dinner table with bright, unmistakable lemon.