Is Lemongrass a Perennial? What You Need to Know Before Planting

• Lemongrass is a perennial in USDA zones 9 (or possibly 8) and above.
• Lemongrass can be grown as a perennial in any USDA zone as long as it is properly overwintered.
• Growing conditions affect flavor, so be sure to give your plant the best care according to your USDA zone for optimal ingredients.

Lemongrass is a tall tropical grass that is native to tropical and sub-tropical climates in Asia, Australia, and Africa. As such, it is cold-sensitive and won’t survive winters with freezing temperatures. If you live in a cooler climate, you have two options: Grow lemongrass as an annual and start with a fresh plant every spring or maintain it as a perennial, which requires overwintering it indoors. 

No matter where you live, you can make your lemongrass plant last for several seasons. Here’s how. 

Is Lemongrass a Perennial?

Botanically, lemongrass—a genus comprising 45 species—is a perennial plant. The lemongrass species commonly used for culinary purposes is West Indian lemongrass (Cymbopogon citratus). It is native to Southern India and Sri Lanka and like all lemongrasses, it is only hardy in frost-free climates (USDA zones 10-11)—that’s why it is often grown as an annual.

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How to Grow Lemongrass

Growing lemongrass, whether it’s in garden soil or in a container, is easy if you meet its basic requirements.

• Light: Lemongrass needs at least six hours of full sun every day—anything less, and it will become weak and spindly and have less flavor.
• Soil: The soil needs to be rich, loamy, and loose, with good drainage. Before planting, work a one-inch layer of organic matter into the soil. If your garden soil is unsuitable, plant lemongrass in a raised bed. Lemon grass needs consistent moisture but does poorly in waterlogged soil.
• Potting: Fill a container of at least 12 inches in diameter, or a 5-gallon pot, with high-quality, well-draining potting mix. Make sure the pot has a large drainage hole and some heft so it does not topple over (lemongrass can grow up to six feet tall).
• Planting: Because lemongrass is a cold-sensitive plant, don’t plant (or move the plant outside) until after the last spring frost, preferably once nighttime temperatures consistently hit 60°F. Plant the stalks so the crown is just below the soil surface. 
• Water: Lemongrass needs ample water and deep watering. To keep the soil constantly moist, water as needed. Watering frequency may range from once or twice a week for in-ground plants to daily for container plants in hot weather. To preserve soil moisture, cover the root zone with a 3-inch layer of mulch.
• Fertilizer: Because lemongrass is a grass, it needs a high-nitrogen fertilizer that stimulates foliage growth. Either fertilize at planting time in the spring with a granular slow-release fertilizer or feed the plant every ten days during the spring and summer with a liquid fertilizer diluted to half strength.

How to Overwinter Lemongrass

 To grow lemongrass as a perennial, there are a few things to know about overwintering it.

Indoors

• In USDA Zone 9 and below, move your potted lemongrass indoors once nighttime temperatures drop below 50°F. Lemongrass stops growing in cool weather so there is no point in keeping it outside.
• If the plant is very large and unruly, cut it down to a height of six inches before moving it indoors.
• Large containers are best overwintered in a basement or garage where temperatures remain consistently above the 50°F threshold all winter. Because the plant is not actively growing, it will only need occasional watering—just enough to keep the soil from drying out.
• To extend the growing season, you can also overwinter the plant inside your home. Place it in a south-facing window to give it maximum sunlight, away from heat vents and radiators. Continue to water but stop fertilizing it. Eventually, growth will slow down, and it will enter dormancy. To counter the overly dry indoor air, place the pot on a pebble tray or use a humidifier.

Outdoors

• In Zones 10-11, you don’t need to take any protective methods to get your lemongrass through the winter except watering in the absence of rain.
• In Zone 9, instead of overwintering your plants indoors, you can try to overwinter the plant outdoors by applying a 3-inch layer of mulch to insulate the roots against freezing temperatures.
• Lemongrass can temporarily withstand temperatures as low as 15°F degrees so its roots may survive winters as low as in Zone 8, but the aboveground parts will die back.

How to Harvest Lemongrass

Lemongrass stalks can be harvested at any time once the stalks are 12 inches tall and about 1/2 inch thick. How long it takes for stalks to reach that stage depends on the growing conditions. Because of less ideal light, lemongrass indoors tends to grow slower than outdoors. Harvest mature older stalks on the outer edge of the clump first. 

Cut the stalks at ground level using a sharp knife or pruners. Alternatively, you can also pull off entire stalks. Push the stalk to the side, twist, and pull it off with its base, which resembles a scallion. This won’t harm the plant, but make sure there are roots left so the plant can regrow.